This is a unique rectifier, in which the alternating current is
rectified by being sent through a commutator which is rotated by a
small alternating current motor, similar to the way the alternating
current generated in the armature of a direct current generator is
rectified in the commutator of the machine. The Stahl rectifier
supplies the alternating current from a transformer instead of
generating it as is done in a direct current generator. Brushes which
bear on the commutator lead to the charging circuit.
The Stahl rectifier is suitable for the larger service stations. It
gives an interrupted direct current. It is simple in construction and
operation, and is free of delicate parts.
Other Charging Equipment
If there is no electric lighting in the shop, it will be necessary to
install a generator and a gas, gasoline, or steam engine, or a
waterwheel to drive it. A 10 battery belt driven generator may be used
in such a shop, and may also, of course, be used with a separate
motor. The generator should, of course, be a direct current machine.
The size of the generator will depend upon the average number of
batteries to be charged, and the amount of money available. Any of the
large electrical manufacturers or supply houses will give any
information necessary for the selection of the type and size of the
outfit required.
If an old automobile engine, and radiator, gas tank, etc., are on
hand, they can be suitably mounted so as to drive the generator.
CHARGING BENCH
[Fig. 65. Charging Bench with D.P.D.T. Switch for Each Battery]
Figures 47 and 65 show charging benches in operation. Note that they
are made of heavy stock, which is of course necessary on account of
the weight of the batteries. The top of the charging bench should be
low, to eliminate as much lifting of batteries as possible. Figure 66
is a working drawing of the bench illustrated in Figure 65. Note the
elevated shelf extending down the center. This is convenient for
holding water bottle, acid pitcher, hydrometer. Note also the strip
"D" on this shelf, with the voltmeter hung from an iron bracket. With
this arrangement the meter may be moved to any battery for voltage,
cadmium, and high rate discharge readings. It also has the advantage
of keeping the volt meter in a convenient and safe place, where it is
not liable to have acid spilled on it, or to be damaged by rough
handling. In building the bench shown in Figure 66, give each part a
coat of asphaltum paint before assembling. After assembling the bench
give it two more coats of asphaltum paint.
[Fig. 66 Working drawing of charging bench shown in Fig. 65]
Figures 67, 68, 69 and 70 show the working plans for other charging
benches or tables. The repairman should choose the one which he
considers most suitable for his shop. In wiring these benches, the
elevated shelf shown in Figure 66 may be added and the double pole,
double throw switches used. Instead of these switches, the jumpers
shown on the benches illustrated in Figure 47 may be used. If this is
done, the elevated shelf should also be installed, as it is a great
convenience for the hydrometer, voltmeter, and so on, as already
described.
As for the hydrometer, thermometer, etc., which were listed on page 96
as essential accessories of a charging bench, the Exide vehicle type
hydrometer is a most excellent one for general use. This hydrometer
has a round bulb and a straight barrel which has projections on the
float to keep the hydrometer in an upright position when taking
gravity readings. The special thermometer is shown in Figure 37. A
good voltmeter is shown in Figure 121. This voltmeter has a 2.5 and a
25 volt scale, which makes it convenient for battery work. It also
gives readings of a .2 and 2.0 to the left of the zero, and special
scale markings to facilitate the making of Cadmium tests as described
on page 174. As for the ammeter, if a motor-generator set, Tungar
Rectifier or a charging-rheostat is used, the ammeter is always
furnished with the set. If a lamp bank is used, a switchboard type
meter reading to about 25 amperes is suitable. With the constant
potential system of charging, the ammeters are furnished with the
motor-generator set. They read up to 300 amperes.
The bottles for the distilled water and electrolyte are not of special
design and may be obtained in local stores, There are several special
water bottles sold by jobbers, and they are convenient, but not
necessary. Figure 133 shows a very handy arrangement for a water or
acid bottle.
[Fig. 67 Working drawing of eight foot charging bench]
[Fig. 68 Working drawing of a ten foot charging bench]
[Fig. 69 Working drawing of a twelve foot charging bench]
[Fig. 70 Working drawing of a twelve foot charging bench (without
drain rack)]
[Fig. 71 Working drawing of a two man work bench to be placed
against a wall]
[Fig. 72 Working drawing of a double, four man work bench, with two
tool drawers for each man]
WORK BENCH
A work bench is more of a standard article than the charging bench,
and there should be no trouble in building one. Figure 38 illustrates
a good bench in actual use. A vise is, of course, necessary, and the
bench should be of solid construction, and should be given several
coats of asphaltum paint.
[Fig. 73 Working drawing of a two man, double work bench]
Figure 71 shows a single work bench which may be placed against a
wall. Figures 72 and 73 show double work benches. Note that each bench
has the elevated shelf, which should not, under any consideration be
omitted, as it is absolutely necessary for good work. The tool drawers
are also very convenient.
It is best to have a separate "tear down" bench where batteries are
opened, as such a bench will be a wet, sloppy place and would not be
suitable for anything else. It should be placed near the sink or wash
tank, as shown in the shop layouts illustrated in Figures 136 to 142.
SINK OR WASH TANK
[Fig. 74]
Fig. 74. Sink with Faucet, and Extra Swinging Arm Pipe for
Washing Out Jars. Four Inch Paint Brush for Washing Battery
Cases
An ordinary sink may be used, as shown in Figure 74. This figure also
shows a convenient arrangement for washing out jars. This consists of
a three-fourths inch pipe having a perforated cap screwed over its
upper end. Near the-floor is a valve which is normally held closed by
a spring, and which has attached to it a foot operated lever. In
washing sediment out of jars, the case is inverted over the pipe, and
the water turned on by means of the foot lever. A number of fine,
sharp jets of water are thrown up into the jar, thereby washing out
the sediment thoroughly.
If an ordinary sink is used, a settling tank should be placed under
it, as shown in Figure 75. Otherwise, the drain pipe may become
stopped up with sediment washed out of the jars. Pipe B is removable,
which is convenient in cleaning out the tank. When the tank is to be
cleaned, lift pipe B up very carefully and let the water drain out
slowly. Then scoop out the sediment, rinse the tank with water, and
replace pipe B. In some places junk men will buy the sediment, or
"mud," as it is called.
[Fig. 75 Settling tank to be used with sink shown in Fig. 74]
Figures 76 and 77 give the working drawings for more elaborate wash
tanks. The water supply shown in Figure 74 may be used here, and the
drain pipe arrangement shown in Figure 75 may be used if desired.
[Fig. 76 Working drawing of a wash tank]
[Fig. 77 Working drawing of a wash tank]
LEAD BURNING (WELDING) OUTFIT
In joining the connectors and terminals to the positive and negative
posts, and in joining plate straps to form a "group," the parts are
joined or welded together, melting the surfaces to be joined, and then
melting in lead from sticks called "burning lead." The process of
joining these parts in this manner is known as "lead burning."
Directions for "lead burning" are given on page 210.
There are various devices by means of which the lead is melted during
the "lead burning" process. The most satisfactory of these use a hot,
pointed flame. Where such a flame is not obtainable, a hot carbon rod
is used.
The methods are given in the following list in the order of their
efficiency:
1. Oxygen and Acetylene Under Pressure in Separate Tanks. The gases
are sent through a mixing valve to the burning tip. These gases give
the hottest flame.
2. Oxygen and Hydrogen Under Pressure in Separate Tanks, Fig. 78. The
flame is a very hot one and is very nearly as satisfactory as the
oxygen and acetylene.
[Fig. 78]
Fig. 78. Hydrogen-Oxygen Lead Burning Outfit. A and B are Regulating
Valves. C is the Safety Flash Back Tank. D is the Mixing Valve. E is
the Burning Tip.
3. Oxygen and Illuminating Gas. This is a very satisfactory method,
and one that has become very popular. In this method it is absolutely
necessary to have a flash back tank (Fig. 79) in the gas line to
prevent the oxygen from backing up into the gas line and making a
highly explosive mixture which will cause a violent explosion that may
wreck the entire shop.
[Fig. 79 Flash-back tank for lead burning outfit]
To make such a trap, any strong walled vessel may be used, as shown in
Figure 79. A six to eight inch length of four inch pipe with caps
screwed over the ends will make a good trap. One of the caps should
have a 1/2 inch hole drilled and tapped with a pipe thread at the
center. This cap should also have two holes drilled and tapped to take
a 1/4 inch pipe, these holes being near the inner wall of the large
pipe, and diametrically opposite one another.
Into one of these holes screw a short length of 1/4 inch pipe so Fig.
79. Flash-Back Tank for Lead Burning Outfit that it comes flush with
the inner face of the cap. This pipe should lead to the burning outfit.
Into the other small hole screw a length of 1/4 inch pipe so that its
lower end comes within 1/2 inch of the bottom of the trap. This pipe
is to be connected to the illuminating gas supply.
To use the trap, fill within one inch of top with water, and screw a
1/2 inch plug into the center hole. All connections should be airtight.
4. Acetylene and Compressed Air. The acetylene is bought in tanks, and
the air compressed by a pump.
5. Hydrogen and Compressed Air. This is the method that was very
popular several years ago, but is not used to any extent at present
because of the development of the first three methods. A special torch
and low pressure air supply give a very satisfactory flame.
6. Wood Alcohol Torch. A hand torch with a double jet burner gives a
very clean, nonoxidizing flame. The flame is not as sharp as the
oxygen flame, and the torch is not easily handled without the use of
burning collars and moulds. The torch has the advantage of being
small, light and portable. A joint may be burned without removing the
battery from the car.
7. Gasoline Torch. A double jet gasoline torch may be used, provided
collars or moulds are used to prevent the lead from running off. The
torch gives a broad flame which heats the parts very slowly, and the
work cannot be controlled as easily as in the preceding methods.
[Fig. 80 Carbon lead burning outfit]
8. Carbon Arc. This is a very simple method, and requires only a spare
6 volt battery, a 1/4 inch carbon rod, carbon holder, cable, and clamp
for attaching to battery. This outfit is shown in Fig. 80. It may be
bought from the American Bureau of Engineering, Inc., Chicago, Ill.
This outfit is intended to be used only when gas is not available, and
not where considerable burning is to be done.
In using this outfit, one terminal of an extra 6 volt battery is
connected by a piece of cable with the connectors to be burned. The
contact between cable and connector should be clean and tight. The
cable which is attached to the carbon rod is then connected to the
other terminal of the extra battery, if the battery is not fully
charged, or to the connector on the next cell if the battery is fully
charged. The number of cells used should be such that the carbon is
heated to at least a bright cherry red color when it is touching the
joint which is to be burned together.
Sharpen the carbon to a pencil point, and adjust its position so that
it projects from the holder about one inch. Occasionally plunge the
holder and hot carbon in a pail of water to prevent carbon from
overheating. After a short time, a scale will form on the surface of
the carbon, and this should be scraped off with a knife or file.
In burning in a connector, first melt the lead of the post and
connector before adding the burning lead. Keep the carbon point moving
over all parts to be joined, in order to insure a perfectly welded
joint.
9. Illuminating Gas and Compressed Air. This is the slowest method of
any. Pump equipment is required, and this method should not be used
unless none of the other methods is available.
The selection of the burning apparatus will depend upon individual
conditions as well as prices, and the apparatus selected should be one
as near the beginning of the foregoing list as possible. Directions
for the manipulation of the apparatus are given by the manufacturers.
The most convenient arrangement for the lead burning outfit is to run
pipes from one end of the work bench to the other, just below the
center shelf. Then set the gas tanks at one end of the bench and
connect them to the pipes. At convenient intervals have outlets for
attaching the hoses leading to the torch.
EQUIPMENT FOR HANDLING SEALING COMPOUND
(a) Stove. Where city gas is available, a two or three burner gas
stove or hot-plate should be used. Where there is no gas supply, the
most satisfactory is perhaps an oil stove. It is now possible to get
an odorless oil stove which gives a hot smokeless flame which is very
satisfactory. In the winter, if a coal stove is used to heat the shop,
the stove may also be used for heating the sealing compound, but it
will be more difficult to keep the temperature low enough to prevent
burning the compound.
(b) Pot or Kettle. An iron kettle is suitable for use in heating
compound. Special kettles, some of which are non-metallic, are on the
market, and may be obtained from the jobbers.
(c) An iron ladle should be obtained for dipping up compound, and for
pouring compound when sealing a battery. Figure 81 shows a convenient
form of ladle which has a pouring hole in the bottom. A taper pin,
which is raised by the extra handle allows a very fine stream of
compound to be poured.
The exact size of the ladle is not important, but one which is too
heavy to be held in one hand should not be used.
(d) Several old coffee pots are convenient, and save much time in
sealing batteries.
Sealing compound is a combination of heavy residues produced by the
fractional distillation of petroleum. It is not all alike-that
accepted for factory use and distribution to Service Stations must
usually conform to rigid specifications laid down by the testing
laboratories governing exact degrees of brittleness, elongation,
strength and melting point. For these qualities it is dependent upon
certain volatile oils which may be driven off from the compound if the
temperature of the molten mass is raised above the comparatively low
points where some of these oils begin to volatilize off as gaseous
vapor or smoke.
Compound from which certain of these valuable constituent oils have
been driven off or "burned out" through overheating is recognized
through too great BRITTLENESS and SHRINKAGE on cooling, causing
"CRACKED COMPOUND" with all of its attending difficulties.
[Fig. 81 Pouring ladle]
Do not put too much cold compound in the kettle to begin with. It is
not advisable to carry much more molten compound in the kettle at any
time than can easily be dipped out-cold compound may be added during
the day as needed. When there is considerable cold compound in the
kettle, and the heating flame is applied, the lower bottom part of
the mass next to the surface of the iron is brought to a melting point
first-heat must be conveyed from this already hot part of the compound
upward throughout the whole mass-so that before the top part of it is
brought to a molten condition the lower inside layers are very hot
indeed. If there is too much in the kettle these lower layers are
necessarily raised in temperature beyond the point where they lose
some of their volatile oils-they are "burned" before the whole mass of
compound can be brought to a molten state.
Do not use too large a heating flame under the kettle for the same
reasons. A flame turned on "full blast" will certainly "burn" the
bottom layers before the succeeding layers above are brought to the
fusion point. USE A SLOW FLAME and TAKE TIME IN MELTING UP THE
COMPOUND. It PAYS in the resulting jobs.
The more compound is heated, the thinner it becomes--it should never be
allowed to become so hot that it flows too freely--it should never
exceed the viscosity of medium molasses. It should flow freely enough
to run in all narrow spaces but NOT freely enough to flow THROUGH them
before it cools.
Stir the kettle frequently during the day. It is advisable about once
a week to work as much compound out of the kettle as possible, empty
that still remaining, clean the kettle out, and start with fresh
compound.
NEVER USE OLD COMPOUND OVER AGAIN--that is, do not throw compound
that has been dug out of used batteries into the kettle with the new
compound. The old compound is no doubt acid soaked, and this acid will
work through the whole molten mass, making a satisfactory job a very
doubtful matter indeed.
Cold weather hardens sealing compound, of course, and renders it
somewhat brittle and liable to crack. This tendency could be overcome
by using a softer compound, but, on the other hand, compound so soft
that it would have no tendency to crack in cold weather would be so
soft in warm weather that it would fail to hold the assembly with the
necessary firmness and security. It is far better policy to run the
risk of developing a few cracks in the winter than a loose assembly in
summer. Surface cracks developed in cold weather may be easily
remedied by stripping off the compound around the crack with a heated
tool, flashing with the torch and quickly re-sealing according to the
above directions.
It is not practical to work any oil agent, such as paraffin or castor
oil, into the compound in an effort to soften it for use in cold
weather.
SHELVING AND RACKS
The essential things about shelving in a battery shop are, that it
must be covered with acid-proof paint, and must be made of heavy
lumber if it is to carry complete batteries. Figure 82 shows the heavy
shelving required in a stock-room, while Figure 83 shows the lighter
shelving which may be used for parts, such as jars, cases, extra
plates, and so on.
[Fig. 82]
Fig. 82. Typical Stockroom, Showing Heavy Shelving Necessary for
Storing Batteries.
Figures 84 and 85 show two receiving racks for batteries which come in
for repairs. In many shops batteries are set on the floor while
waiting for repairs. If there is plenty of floor space, this practice
is not objectionable. In any case, however, it improves the looks of
the shop, and makes a better impression on the customer to have racks
to receive such batteries. Note that the shelves are arranged so as to
permit acid to drain off. Batteries often come in with wet, leaky
cases, and this shelf construction is suitable for such batteries.
The racks shown in Figures 86 and 87 are for repaired batteries, new
batteries, rental batteries, batteries in dry storage, and for any
batteries which do not have wet leaky cases.
Figures 88 and 89 show racks suitable for new batteries which have
been shipped filled with electrolyte, batteries in "wet" or "live"
storage, rental batteries, and so on. Note that these racks are
provided with charging circuits so that the batteries may be given a
low charge without removing them from the racks. Note also that the
shelves are spaced two feet apart so as to be able to take hydrometer
readings, voltage readings, add water, and so on, without removing the
batteries from the racks.
BINS
Figure 90 gives the dimensions for equipment bins suitable for covers,
terminals, inter-cell connectors, jars, cases, and various other
parts. These bins can be made with any desired number of sections, and
additional sections built as they are needed.
[Fig. 83]
Fig. 83. Corner of Workshop, Showing Lead Burning Outfit, Workbench
and Vises.
[Fig. 84 Working drawing of a 6-foot receiving rack]
[Fig. 85 Working drawing of a 12-foot receiving rack]
[Fig. 86 Working drawing of an 8-foot rack for repaired batteries,
new batteries, rental batteries, batteries in dry storage, etc.]
[Fig. 87 Working drawing of a 16-foot rack for repaired batteries,
new batteries, rental batteries, batteries in dry storage, etc.]
[Fig. 88 Working drawing of a 16-foot rack suitable for new batteries
(shipped filled and fully charged), batteries in "wet" storage,
rental batteries, etc.]
[Fig. 88b End view of rack in Fig. 88]
[Fig. 89 Working drawing of a 12-foot rack suitable for new batteries
(shipped filled and fully charged), batteries in "wet" storage,
rental batteries, etc.]
[Fig. 89b End view of rack in Fig. 89]
[Fig. 90 Working drawing of bins suitable for battery parts]
BATTERY STEAMER
Steaming is the most satisfactory method of softening sealing
compound, making covers and jars limp and pliable. An open flame
should never be used for this work, as the temperature of the flame is
too high and there is danger of burning jars and covers and making
them worthless. With steam, it is impossible to damage sealing
compound or rubber parts.
A soft flame from a lead burning torch is used to dry out the channels
in the covers before sealing, and is run over the compound quickly to
make the compound flow evenly and unite with the jars and covers. But
in such work the flame is used for only a few seconds and is not
applied long enough to do any damage.
With a steaming outfit, it is also possible to distill water for use
in mixing electrolyte and replacing evaporation in the cells. The only
additional equipment needed is a condenser to condense the steam into
water.
[Fig. 91]
Fig. 91. Battery Steamer, with Steam Hose for Each Cell
[Fig. 92 Condenser for use with battery steamer]
Figure 91 shows a steaming outfit mounted on a wall, and shows the
rubber tube connections between the several parts. The boiler is set
on the stove, water being supplied from the water supply tank which is
hung above the boiler to obtain gravity feed. The water supply tank is
open at the top, and is filled every morning with faucet water. This
tank is suitable for any shop, even though a city water supply is
available. A water pipe from the city lines may be run to a point
immediately above the tank and a faucet or valve attached. Where there
is no city water supply, the tank may, of course, be filled with a
pail or pitcher.
The boiler is equipped with a float operated valve which maintains a
one to one and one-half inch depth of water. As the water boils away,
the float lowers slightly and allows water to enter the boiler. In
this way, the water is maintained at the proper level at all times. A
manifold is fitted to the boiler and has six openings to which lengths
of rubber tubing are attached. These tubes are inserted in the vent
holes of the battery which is to be steamed. Any number of the steam
outlets may be opened by drawing out the manifold plunger valve to the
proper point. When distilling water, a tube is attached to one of the
steam outlets as shown, and connected to the condenser as shown. A
bottle is placed under the distilled water outlet to collect the
distilled water.
Cooling water enters the condenser through the tubing shown attached
to the condenser at the lower right-hand edge. The other end of this
tube is attached to the water faucet, or other cooling water supply.
The cooling water outlet is shown at the lower left hand edge of the
condenser. The cooling water inlet and outlet are shown in Figure 92.
If there is no city water supply, a ten or twenty gallon tank may be
mounted above the condenser and attached by means of a rubber tube to
the cooling water inlet shown at the lower right hand edge of the
condenser in Figure 92. A similar tank is placed under the cooling
water outlet. The upper tank is then filled with water. When the water
has run out of the upper tank through the condenser and into the lower
tank, it is poured back into the upper tank. In this way a steady
supply of cooling water is obtained.
[Fig. 93 Steaming box in which entire battery is set]
Another type of steamer uses a steaming box, Figure 93. The battery is
placed in the box and steam is sent in through the cover. The boiler
has only one steam outlet, and this is connected to the box by means
of a hose.
[Fig. 94 Special bench for battery steamer]
If desired, a special bench may be made for the steaming outfit, as
shown in Figure 94.
The other tools needed for opening batteries, as given in the list on
page 97 are standard articles, and may be obtained at any hardware
store, except the terminal tongs, which should be purchased from a
battery supply house.
[Fig. 95 Battery terminal tongs]
Figure 95 illustrates the use of terminal tongs. Battery terminals
usually stick so tight that they must be forced out with pliers or
other tools. Here is shown a pair of tongs that makes easy work of the
job. One end has a fork and the other is shaped to come between the
fork. It is placed on the battery terminal, as shown, and when the
handles are brought together the terminal attached to the battery lead
is forced out without marring any of the parts.
EQUIPMENT FOR LEAD BURNING (WELDING)
Plate Burning Rack
The plates which compose a "group" are joined to the plate connecting
strap to which the post is attached. The plates are "burned" to the
strap, and this must be done in such a manner that the plates are
absolutely parallel, that the distance between plates is correct, and
that the top surface of the strap is at right angles to the surface of
the plates. These conditions are necessary in order that the positive
and negative groups may mesh properly, that the complete element,
consisting of the plates and separators may fit in the jar properly,
and that the cell covers may fit over the posts easily.
[Fig. 96]
Fig. 96. Universal Plate Burning Rack. Will Hold Three Groups of
Plates at One Time. Designed for Standard and Special Plates
In order to secure these conditions, plates that are to be burned to
the strap are set in a "burning rack," shown in Figs. 96 and 97, which
consists mainly of a base upon which the plate rest, and a slotted bar
into which the lugs on the plates fit. The distance between successive
slots is equal to the correct distance between the plates of the
group. An improved form of burning rack has a wooden base which has
slots along the side. The plates are set into these slots and are thus
held in the correct position at both top and bottom.
[Fig. 97 Plate burning rack for standard 1/8 inch, and thin plates]
Fig. 97 shows a rack for use with 1/8 inch and 7-64 inch plates. Fig.
96 shows a "Universal" rack which may be used with both the 1/8 and
7-64 inch plates, and also many special plates.
The guide-bar, or "comb," E, has slots along two sides, the base
having corresponding slots, as shown. To accommodate different sized
plates, the comb may be raised or lowered, and the uprights may be
moved back and forth in two slots, one of which is shown at F. In
using this rack, the plates are set in position, with their lower
edges in the slots of the base, and their lugs in the slots in the
comb. The plates are in this way held at opposite corners, and are
absolutely straight and parallel.
Special fittings are provided to simplify the work of burning. A bar,
D, fits along the edge of the comb, and holds the lugs of the plates
firmly in the slots. This bar is movable to any part of the comb,
being held by two spring clips, C. Two bars, A and B, which are
adjustable, make a form around the plate lugs which will prevent the
hot lead from running off while burning in the plates.
Instructions for burning on plates are given on page 217.
The triangular scraper, steel wire brush, coarse files and smoked or
blue glasses are all standard articles and may be obtained from any
supply house. The burning collars are made of iron, and are set over
the end of inter-cell connectors when burning these to the posts, see
Figure 98. Experienced repairmen generally do not use them, but those
who have trouble with the whole end of the connector melting and the
lead running off should use collars to hold in the lead.
[Fig. 98 Burning collars]
The Burning Lead Mould
In every shop there is an accumulation of scrap lead from post
drillings, old connecting straps, old plate straps, etc. These should
be kept in a special box provided for that purpose, and when a
sufficient amount has accumulated, the lead should be melted and run
off into moulds for making burning-lead.
The Burning Lead Mould is designed to be used for this purpose. As
shown in Fig. 99, the mould consists of a sheet iron form which has
been pressed into six troughs or grooves into which the melted lead is
poured. This sheet iron form is conveniently mounted on a block of
wood which has a handle at one end, making it possible to hold the
mould while hot without danger of being burned. A sheet of asbestos
separates the iron form from the wood, thus protecting the wood from
the heat of the melted lead. A hole is drilled in the end of the
handle to permit the mould being hung on a nail when not in use. The
grooves in the iron form will produce bars of burning lead 15 inches
long, 5-16 inch thick, 3/8 inch wide at the top, and 1/4 inch wide at
the bottom.
[Fig. 99]
Fig. 99. Burning-Lead Moulds, and Burning Sticks Cast in Them
The advantage of this type of Burning Lead Mould over a cast iron
mould is obvious. The form, being made of sheet iron, heats up very
quickly, and absorbs only a very small amount of heat from the melted
lead. The cast-iron mould, on the other hand, takes so much heat from
the melted lead that the latter cools very quickly, and is hard to
handle.
An iron pot that will hold at least ten pounds of molten lead should
be used in melting up lead scraps for burning sticks.
When the metal has become soft enough to stir with a clean pine stick
skim off the dross. Continue heating metal until slightly yellow on
top.
With a paddle or ladle drop in a cleaning compound of equal parts of
powdered rosin, borax and flower of sulphur. Use a teaspoonful for a
ten-pound melting and make sure the compound is perfectly dry.
Stir a little and if metal is at proper heat there will be a flare,
flash or a little burning. A sort of tinfoil popcorn effect will be
noticed floating on top of the metal. Stir until this melts down. Have
your ladle hot and skim off soft particles. Dust the mould with mould
compound, a powder which makes the lead fill the entire grooves, and
not become cool before it does.
When everything is ready, fill the ladle and pour the lead into one of
the grooves. Hold the ladle above one end of the groove while pouring,
and do not move it along the groove. Fill the other grooves in a
similar manner.
Post Builders. These are moulds which are set over the stumps of posts
which have been drilled short in removing the inter-cell connectors.
Lead is then melted in with a burning flame to build the post up to
the proper height. Figure 100 shows a set of post-builders, and Figure
101 illustrates their use.
[Fig. 100 Set of post builders]
[Fig. 101 Illustrating use of post builders]
EQUIPMENT FOR GENERAL WORK ON CONNECTORS AND TERMINALS
Moulds for Casting Inter-Cell Connectors, Terminals, Terminal
Screws, Taper Lugs, Plate Straps, Etc.
Figure 102 shows a plate strap mould with which three straps and posts
may be cast in one minute. It has a sliding movable tooth rack for
casting an odd or even number of teeth on the strap.
[Fig. 102 Plate strap mould]
Figure 103 shows a Link Combination Mould which casts five inter-cell
connectors for use on standard 7, 9, 11, 13 and 15 plate batteries,
four end connectors (two Dodge tapers, and standard tapers, negative
and positive), one end connector with 3/8 inch cable used on 12 volt
Maxwell battery and on all other cars a wire cable, and one small wire
to connect with end post on batteries requiring direct connection. It
also casts two post support rings to fit standard size rubber covers
and to fit posts cast with plate strap mould, and two washers which
are often needed when installing needed when installing new or rental
batteries.
[Fig. 103 and Fig. 104: Link combination mould, and castings made
in it]
Figure 104 shows the parts which may be made with this mould.
[Fig. 105 Cell connector mould]
[Fig. 106 Production type strap mould]
Figure 105 shows a cell connector mould which casts practically all
the cell connectors used on standard 7, 9, 11, 13 and 15 plate
batteries. This mould is similar to the Link Combination Mould shown
in Figure 103.
[Fig. 107 Indexing device for strap mould]
[Fig. 108 Castings made in strap mould]
Figure 106 shows a production type strap mould which is designed to be
used by large battery shops. Forty-two styles of straps are, cast by
this mould. This mould has an indexing device as shown in Figure 107,
which is adjusted by means of a screw for moulding the straps for any
number of plates from seven to nineteen. Figure 109 shows some of the
castings which are made with this mould.
[Fig. 109 Terminal mould and castings made in it]
Figure 109 shows a Terminal Mould which casts five reversible end
terminal connectors, a cable connector, such as is used on the
Maxwell battery, and two washers often needed in making a tight
connection.
[Fig. 110 Screw mould]
Figure 110 shows a Screw Mould which casts standard square lead leads
on four screws in one operation, two 5/8 inch and two 3/8 inch. This
mould has a screw adjustment in the base which makes each cavity
adaptable to any length screw.
EQUIPMENT FOR WORK ON CASES
The acid proof asphaltum paint, paint brushes, wood chisels, wood
plane, and earthenware jars are all standard articles.
[Fig. 111 Battery turntable]
Figure 111 shows a battery turntable which is very convenient when
painting cases, lead burning, etc.
TOOLS FOR GENERAL WORK
Most of the articles in this list require no explanation. Some of
them, however, are of special construction.
Separator Cutter. Some battery supply houses sell special separator
cutters, but a large size photograph trimmer is entirely satisfactory.
[Fig. 112]
Fig. 112. Plate Press for Pressing Swollen,
Bulged Negatives (After Plates Have Been Fully
Charged)
[Fig. 113]
Fig. 113. Inserting Plate Press Boards Between
Negatives Preparatory to Pressing
Plate Press. Figure 112 shows a special plate press in which the
plates are pressed between wooden jaws. No iron can come into contact
with the plates. This is a very important feature, since iron in
solution causes a battery to lose its charge very quickly. This press
is made of heavy hardwood timbers, and may be set on a bench or
mounted on the wall. A set of lead coated troughs carry away the acid
which is squeezed from the plates.
[Fig. 114 Showing how negatives should be placed in the plate
press]
This press is designed for pressing negative plates, the active
material of which has become bulged or swollen. A plate in this
condition has a low capacity and cannot give good service. Swollen
negatives often make it impossible to replace the plates in a jar.
When negatives are found to be bulged or swollen, the battery must be
fully charged, and the negatives then pressed. To do this, plate press
boards, which are of acid proof material, and of the proper thickness
are inserted between the negatives, as shown in Figure 113, and the
plates are then set in the press is shown in Figure 114.
[Fig. 115 Negative group before and after pressing]
Figure 115 shows a group before and after pressing. Note that pressing
has forced the active material back into the grid where it must be if
the plates are to give good service. Never send out a battery with
swollen or bulged negatives.
Slightly buckled negatives may also be straightened out in the Plate
Press. Positives do not swell or bulge as they discharge, but shed the
active material. They are therefore not pressed Positives buckle, of
course, but should never be pressed to straighten them. The lead
peroxide of the positive plates is not elastic like the spongy the
negatives, and if positives are pressed to straighten them the paste
will crack and break from the grid. Slightly buckled positives may be
used, but if they are so badly buckled that it is impossible to
reassemble the element or put the element back into the jars, they
should be discarded.
[Fig. 116 Battery carrier]
[Fig. 117 Battery truck]
Battery Carrier. Figure 116 shows a very convenient battery carrier,
having a wooden handle with two swinging steel hooks for attaching to
the battery to be carried. With this type of carrier no strain is put
on the handle, as is the case if a strap is used.
Battery Truck. When a battery must be moved any considerable distance,
a truck, such as that shown in Figure 117 should be used. This truck
may easily be made in the shop, or may be made at a reasonable cost in
a carpenter shop. The rollers should be four inches or more in
diameter and should preferably be of the ball-bearing type. Rubber
tires on the rollers are a great advantage, since the rubber protects
the rollers from acid and also eliminates the very disagreeable noise
which iron wheels make, especially in going over a concrete floor or
sidewalk. The repairman need not make his truck exactly like that
shown in Figure 117, which is merely shown to give a general idea of
how such a truck should be constructed.
The truck shown in Figure 117 was made from a heavy wooden box. With
this construction lifting batteries is largely eliminated, which is
most desirable, since a battery is not the lightest thing in the
world. The battery is carried in a horizontal position and the truck
is small enough to be wheeled between cars in the shop.
[Fig. 118 Another battery truck]
Another form of battery truck is shown in Figure 118, although this,
is not as good as that shown in Figure 117.
CADMIUM TEST SET AND HOW TO MAKE THE TEST
As the cell voltage falls while the battery is on discharge, the
voltage of the positive plates, and also the voltage of the negative
plates falls. When the battery is charged again the voltages of both
positive and negative plates rise. If a battery gives its rated
ampere-hour capacity on discharge, we do not care particularly how the
voltages of the individual positive and negative groups change. If,
however, the battery fails to give its rated capacity, the fault may
be due to defective positives or defective negatives.
If the voltage of a battery fails to come up when the battery is put
on charge, the trouble may be due to either the positives or
negatives. Positives and negatives may not charge at the same rate,
and one group may become fully charged before the other group. This
may be the case in a cell which has had a new positive group put in
with the old negatives. Cadmium tests made while the battery is on
charge will tell how fully the individual groups are charged.
Since the voltages of the positives and negatives both fall as a
battery is discharged, and rise as the battery is charged, if we
measure the voltages of the positives and negatives separately, we can
tell how far each group is charged or discharged. If the voltage of
each cell of a battery drops to 1.7 before the battery has given its
rated capacity, we can tell which set of plates has become discharged
by measuring the voltages of positives and negatives separately. If
the voltage of the positives show that they are discharged, then the
Positives are not up to capacity. Similarly, negatives are not up to
capacity if their voltage indicates that they are discharged before
the battery has given its rated capacity.
Cadmium readings alone do not give any indication of the capacity of a
battery, and the repairman must be careful in drawing conclusions from
Cadmium tests.
In general it is not always safe to depend upon Cadmium tests on a
battery which has not been opened, unless the battery is almost new.
Plates having very little active material, due to shedding, or due to
the active material being loosened from the grid, will often give good
Cadmium readings, and yet a battery with such plates will have very
little capacity. Such a condition would be disclosed by an actual
examination of the plates, or by a capacity discharge test.
How Cadmium Tests Are Made
To measure the voltages of the positives and negatives separately,
Cadmium is used. The Cadmium is dipped in the electrolyte, and a
voltage reading is taken between the Cadmium and the plates which are
to be tested. Thus, if we wish to test the negatives, we take a
voltage reading between the Cadmium and the negatives, as shown in
Fig. 119. Similarly, if we wish to test the positives, we take a
voltage reading between the Cadmium and the positives, as shown in
Fig 120.
[Fig. 119 Making cadmium test on negative plates]
[Fig. 120 Making cadmium test on positive plates]
In dipping the Cadmium into the electrolyte, we make two cells out of
the battery cell. One of these consists of the Cadmium and the
positives, while the other consists of the Cadmium and the negatives.
If the battery is charged, the Cadmium forms the negative element in
the Cadmium-Positives cell, and is the positive element in the
Cadmium-Negatives cell. The voltage of the Cadmium does not change,
and variations in the voltage readings obtained in making Cadmium
tests are due to changes in the state of charge of the negative and
positive plates which are being tested.
What Cadmium Is: Cadmium is a metal, just like iron, copper, or lead.
It is one of the chemical elements; that is, it is a separate and
distinct substance. It is not made by mixing two or more substances,
as for instance, solder is made by mixing tin and lead, but is
obtained by separating the cadmium from the compounds in which it is
found in nature, just as iron is obtained by treatment of iron ore in
the steel mill.
When Cadmium Readings Should Be Made
1. When the battery voltage drops to 1.7 per cell on discharge before
the battery has delivered its rated ampere-hour capacity, at the
5-hour rate when a discharge test is made.
2. When a battery on charge will not "come up," that is, if its
voltage will not come up to 2.5-2.7 per cell on charge, and its
specific gravity will not come up to 1.280-1.300.
3. Whenever you charge a battery, at the end of the charge, when the
voltage and specific gravity no longer rise, make Cadmium tests to be
sure that both positives and negatives are fully charged.
4. When you put in a new group, charge the battery fully and make
Cadmium tests to be sure that both the new and old groups are fully
charged.
5. When a 20-minute high rate discharge test is made. See page 267.
That Cadmium Readings should be taken only while a battery is in
action; that is, while it is on discharge, or while it is on charge.
Cadmium Readings taken on a battery which is on open circuit are not
reliable.
When you are not using the Cadmium, it should be put in a vessel of
water and kept there. Never let the Cadmium become dry, as it will
then give unreliable readings.
Open Circuit Voltage Readings Worthless
Voltage readings of a battery taken while the battery is on open
circuit; that is, when no current is passing through the battery, are
not reliable. The voltage of a normal, fully charged cell on open
circuit is slightly over 2 volts. If this cell is given a full normal
discharge, so that the specific gravity of its electrolyte drops to
1.150, and is allowed to stand for several hours after the end of the
discharge, the open circuit voltage will still be 2 volts. Open
circuit voltage readings are therefore of little or no value, except
when a cell is "dead," as a dead cell will give an open circuit
voltage very much less than 2, and it may even give no voltage at all.
What the Cadmium Test Set Consists of
The Cadmium Tester consists of a voltmeter, Fig. 121, and two pointed
brass prods which are fastened in wooden handles, as shown in Fig.
122. A length of flexible wire having a terminal at one end is
soldered to each prod for attachment to the voltmeter. Fastened at
right angles to one of the brass prods is a rod of pure cadmium.
[Fig. 121 Special cadmium test voltmeter, & Fig. 122 Cadmium
test leads]
Cadmium tests may be made with any accurate voltmeter which gives
readings up to 2.5 volts in divisions of .05 volt.
The instructions given below apply especially to the special AMBU
voltmeter but these instructions may also be used in making cadmium
tests with any voltmeter that will give the correct reading.
The AMBU Cadmium Voltmeter
Fig. 121 is a view of the special AMBU Voltmeter, which is designed to
be used specially in making Cadmium tests. Fig. 122 shows the Cadmium
leads. The four red lines marked "Neg. Charged," "Neg. Discharged,"
"Pos. Charged," and "Pos. Discharged," indicate the readings that
should be obtained. Thus, in testing the positives of a battery on
charge, the pointer will move to the line which is marked "Pos.
Charged," if the positive plates are fully charged. In testing the
negatives, the pointer will move to the line marked "Neg. Charged,"
which is to the left of the "0" line, if the negatives are fully
charged, and so on. Figs. 123, 124, 125 and 126 show the pointer
in the four positions on the scale which it takes when testing fully
charged or discharged plates. In each figure the pointer is over one
of the red lines on the scale. These figures also show the readings,
in volts, obtained in making the cadmium tests on fully charged or
completely discharged plates.
[Fig. 123 Voltmeter showing reading obtained when testing charged
negative; & Fig. 124 Showing reading obtained when testing
charged positives]
[Fig. 125 Voltmeter showing reading obtained when testing discharged
negatives; and Fig. 126 Showing reading obtained when testing
discharged positives]
If Pointer Is Not Over the "0" Line: It sometimes happens, in shipping
the instrument, and also in the use of it, that the pointer does not
stand over the "0" line, but is a short distance away. Should you find
this to be the case, take a small screwdriver and turn the screw which
projects through the case, and which is marked "Correct Zero," so as
to bring the pointer exactly over the "0" line on the scale while the
meter has no wires connected to its binding posts.
Connections of Cadmium Leads: In making Cadmium Tests, connect the
prod which has the cadmium fastened to it to the negative voltmeter
binding post. Connect the plain brass prod to the positive voltmeter
binding post. The connections to the AMBU Cadmium Voltmeter are shown
in Fig. 127.
Testing a Battery on Discharge
The battery should be discharging continuously, at a constant, fixed
rate, see page 265.
[Fig. 127 AMBU Cadmium Voltmeter]
Generally, on a starting ability test (see page 267), the positive
Cadmium readings will start at about 2.05 volts for a hard or very new
set of positives, and at 2.12 volts or even higher for a set of soft
or somewhat developed positives, and will drop during the test, ending
at 1.95 volts or less. The negative Cadmium readings will start at
0.23 volt or higher, up to 0.30, and will rise gradually, more
suddenly toward the end if the plates are old, ending anywhere above
0.35 and up to 0.6 to 0.7 for poor negatives.
Short Circuited Cells: In cases of short circuited cells, the voltage
of the cell will be almost down to zero. The Cadmium readings would
therefore be nearly zero also for both positives and negatives. Such a
battery should be opened for inspection and repairs.
Testing a Battery on Charge
The Battery should be charging at the finishing rate. (This i's
usually stamped on the battery box.) Dip the cadmium in the
electrolyte as before, and test the negatives by holding the plain
prod on the negative post of the cell. See Fig. 119. Test the
positives in a similar manner. See Fig. 120. The cell voltage should
also be measured. If the positives are fully charged, the positive
cadmium reading will be such that the pointer will move to the red
line marked "Pos. Charged." See Fig. 125. If you are using an ordinary
voltmeter, the meter will give a reading of from 2.35 to 2.42 volts.
The negatives are then tested in a similar manner. The
negative-cadmium reading on an ordinary voltmeter will be from .175 to
.2 to the left of the "0" line; that is, the reading is a reversed
one. If you are using the special ABM voltmeter, the pointer will move
to the red line marked "Neg. Charged." See Fig. 123. The cell voltage
should be the sum of the positive-cadmium and the negative cadmium
readings.
If the voltage of each cell will not come up to 2.5 to 2.7 volts on
charge, or if the specific gravity will not rise to 1.280 or over,
make the cadmium tests to determine whether both sets of plates, or
one of them, give readings indicating that they are fully charged. If
the positives will not give a reading of at least 2.35 volts, or if
the negatives will not give a reversed reading of at least 0.1 volt,
these plates lack capacity.
In case of a battery on charge, if the negatives do not give a minus
Cadmium reading, they may be lacking in capacity, but, on the other
hand, a minus negative Cadmium reading does not prove that the
negatives are up to hill capacity. A starting ability discharge test
(page 267) is the only means of telling whether a battery is up to
capacity.
Improperly treated separators will cause poor negative-Cadmium
readings to be obtained. The charging rate should be high enough to
give cell voltages of 2.5-2.7 when testing negatives. Otherwise it may
not be possible to get satisfactory negative-Cadmium reading.
Separators which have been allowed to become partly dry at any time
will also make it difficult to obtain satisfactory negative-Cadmium
readings.
HIGH RATE DISCHARGE TESTERS
(See page 265 for directions for making tests.)
Figure 128 shows a high rate discharge cell tester. It consists of a
handle carrying two heavy prongs which are bridged by a length of
heavy nichrome wire. When the ends of the prongs are pressed down on
the terminals of a cell, a current of 150 to 200 amperes is drawn from
the cell. A voltage reading of the cell, taken while this discharge
current is flowing is a means of determining the condition of the
cell, since the heavy discharge current duplicates the heavy current
drawn by the starting motor. Each prong carries a binding post, a low
reading voltmeter being connected to these posts while the test is
made. This form of discharge tester is riot suitable for making
starting ability discharge tests, which are described on page 267.
Other forms of high rate discharge testers are made, but for the shop
the type shown in Figure 128 is most convenient, since it is light and
portable and has no moving parts, and because the test is made very
quickly without making any connections to the battery. Furthermore,
each cell is tested separately and thus six or twelve volt batteries
may be tested without making any change in the tester.
For making starting ability discharge tests at high rates, a carbon
plate or similar rheostat is most suitable, and such rheostats are on
the market.
[Fig. 128 High rate discharge tester]
[Fig. 129 Paraffine dip pot]
PARAFFINE DIP POT
Paper tags are not acid proof, and if acid is spilled on tags tied to
batteries which are being repaired, the writing on the tags is often
obliterated so that it is practically impossible to identify the
batteries. An excellent plan to overcome this trouble is to dip the
tags in hot paraffine after they have been properly filled out. The
writing on the tags can be read easily and since paraffine is acid
proof, any acid which may be spilled on the paraffine coated tags will
not damage the tags in any way.
Figure 129 shows a paraffine dip pot. A small earthenware jar is best
for this purpose. Melt the paraffine slowly on a stove, pour it into
the pot, and partly immerse a 60-watt carbon lamp in the paraffine as
shown. The lamp will give enough heat to keep the paraffine melted,
without causing it to smoke to any extent. After filling out a Battery
Card, dip it into the Paraffine, and hold the card above the pot to
let the excess paraffine run off. Let the paraffine dry before
attaching the tag to the battery, otherwise the paraffine may be
scratched off.
WOODEN BOXES FOR BATTERY PARTS
[Fig. 130]
Fig. 130. Boxes for Holding Parts of Batteries Being Prepared
Figure 130 shows a number of wooden boxes, about 12 inches long, 8
inches wide, and 4 inches deep. These boxes are very useful for
holding the terminals inter-cell connectors, covers, plugs, etc., of
batteries which are dismantled for repairs. Write the name of the
owner with chalk on the end of the box, and rub the name off after the
battery has been put together again. The boxes shown in Figure 130 had
been used for plug tobacco, and served the purpose very well. The
larger box shown in Figure 130 may be used for collecting old
terminals, inter-cell connectors, lead drillings, etc.
EARTHENWARE JARS
The twenty gallon size is very convenient for waste acid, old
separators, and any junk parts which are wet with acid. The jars are
acid proof and will help keep the shop floor dry and anything which
will help in this is most desirable.
ACID CARBOYS
Acid is shipped in large glass bottles around each of which a wooden
box is built to prevent breakage, the combination being called a
"carboy." Since the acid is heavy, some means of drawing it out of the
bottle is necessary. One method is illustrated in Figure 131, wooden
rockers being screwed to the box in which the bottle is placed.
[Fig. 131 A simple method of drawing acid from a carboy]
A very good addition to the rockers shown in Figure 131 is the inner
tube shown in Figure 132. In this illustration the rockers are not
shown, but should be used. The combination of the rockers with the
inner tube gives a very convenient method of pouring acid from a
carboy, since the heavy bottle need not be lifted, and since it helps
keep the floor and the top of the box dry.
[Fig. 132 Use of inner tube to protect box when pouring acid]
The rubber tube shown in Figure 132 is a piece of 4 inch inner tube
which is slit down one side to make it lie flat. Near one end is cut a
hole large enough to fit tightly over the neck of the acid bottle.
Slip this rubber over the neck of the bottle and allow the long end to
hang a few inches over the side of the carboy bottle or box. This is
for pouring acid from a carboy when it is too full to allow the
contents to be removed without spilling. This device will allow the
contents of the carboy to be poured into a crock or other receptacle
placed on the floor without spilling, and also prevents dirt that may
be laying on top of the carboy from falling into the crock.
[Fig. 133 Siphon for drawing acid from carboy]
Figure 133 shows a siphon method for drawing acid from a bottle,
although this method is more suitable for distilled water than for
acid. "A" is the bottle, "B" a rubber stopper, "C" and "D" are 3/8
inch glass or hard rubber tubes, "E" is a length of rubber tubing
having a pinch clamp at its lower end. To use this device, the stopper
and tubes are inserted in the bottle, and air blown or pumped in at
"C," while the pinch clamp is open, until acid or water begins to run
out of the lower end of tubing "E." The pinch clamp is then released.
Whenever acid or water is to be drawn from the bottle the pinch clamp
is squeezed so as to release the pressure on the tube. The water or
acid will flow down the tube automatically as long as the pinch clamp
is held open. The clamp may be made of flat or round spring brass or
bronze. This is bent round at (a). At (c) an opening is made, through
which the part (b) is bent. The clamp is operated by pressing at (d)
and (e). The rubber tubing is passed through the opening between (b)
and (c).
This method is a very good one for the small bottle of distilled water
placed on the charging bench to bring the electrolyte up to the proper
height. The lower end of tube (e) is held over the vent hole of the
cell. The pinch clamp is then squeezed and water will flow. Releasing
the clamp stops the flow of water instantly. If tube (e) is made long
enough, the water bottle may be set on the elevated shelf extending
down the center of the charging bench.
[Fig. 134 Foot pump for drawing acid from carboy]
Figure 134 shows another arrangement, using a tire pump. D and E are
3/8 inch hard rubber tubes. D is open at both ends and has a "T"
branch to which the pump tubing is attached. To operate, a finger is
held over the upper end of D, and air is pumped into the acid bottle,
forcing the acid into the vessel F. To stop the flow of acid, the
finger is removed from D. This stops the flow instantly. This method
is the most satisfactory one when fairly large quantities of acid or
water are to be drawn off.
SHOP LAYOUTS
The degree of success which the battery repairman attains depends to a
considerable extent upon the workshop in which the batteries are
handled. It is, of course, desirable to be able to build your shop,
and thus be able to have everything arranged as you wish. If you must
work in a rented shop, select a place which has plenty of light and
ventilation. The ventilation is especially important on account of the
acid fumes from the batteries. A shop which receives most of its light
from the north is the best, as the light is then more uniform during
the day, and the direct rays of the sun are avoided. Fig. 38 shows a
light, well ventilated workroom.
The floor should be in good condition, since acid rots the wood and if
the floor is already in a poor condition, the acid will soon eat
through it. A tile floor, as described below, is best. A wooden floor
should be thoroughly scrubbed, using water to which baking soda has
been added. Then give the floor a coat of asphaltum paint, which
should be applied hot so as to flow into all cracks in the wood. When
the first coat is dry, several more coats should be given. Whenever
you make a solution of soda for any purpose, do not throw it away when
you are through with it. Instead, pour it on the floor where the acid
is most likely to be spilled. This will neutralize the acid and
prevent it from rotting the wood.
If you can afford to build a shop, make it of brick, with a floor of
vitrified brick, or of tile which is not less than two inches thick,
and is preferably eight inches square. The seams should not be less
than one-eighth inch wide, and not wider than one fourth. They should
be grouted with asphaltum, melted as hot and as thin as possible (not
less than 350° F.). This should be poured in the seams. The brick or
tile should be heated near the seams before pouring in the asphaltum.
When all the seams have been filled, heat them again. After the second
heating, the asphaltum may shrink, and it may be necessary to pour in
more asphaltum.
If possible, the floor should slope evenly from one end of the room to
the other. A lead drainage trough and pipe at the lower end of the
shop will carry off the acid and electrolyte.
It is a good plan to give all work benches and storage racks and
shelves at least two coatings of asphaltum paint. This will prevent
rotting by the acid.
The floor of a battery repair shop is, at best, a wet, sloppy affair,
and if a lead drainage trough is too expensive, there should be a
drain in the center of the floor if the shop is small, and several if
the shop is a large one. The floor should slope toward the drains, and
the drain-pipes should be made of glazed tile.
To keep the feet as dry as possible, rubbers, or even low rubber boots
should be worn. Sulphuric acid ruins leather shoes, although leather
shoes can be protected to a certain extent by dipping them in hot
paraffine.
[Fig. 135 Wooden grating on shop floor to give dry walking
surface for the repairman]
A good plan is to lay a wooden grating over the floor as shown in
Figure 135. Water and acid will run down between the wooden strips,
leaving the walking surface fairly dry. If such a grating is made, it
should be built in sections which may be lifted easily to be washed,
and to permit washing the floor. Keep both the grating and the floor
beneath covered with asphaltum paint to prevent rotting by acid. Once
a week, or oftener, if necessary, sweep up all loose dirt and then
turn the hose on the floor and grating to wash off as much acid as
possible. When the wood has dried, a good thing to do is to pour on
the floor and grating several pails of water in which washing soda or
ammonia has been dissolved.
Watch your floor. It will pay-in better work by yourself and by the
men working for you. Have large earthenware jars set wherever
necessary in which lead drillings, old plates, old connectors, old
separators, etc., may be thrown. Do not let junk cases, jars,
separators, etc., accumulate. Throw them away immediately and keep
your shop clean. A clean shop pleases Your customers, --and satisfied
customers mean success.
On the following pages a number of shop layouts are given for both
large and small shops. The beginner, of course, may not be able to
rent even a small shop, but he may rent part of an established repair
shop, and later rent an entire shop. A man working in a corner of an
established service must arrange his equipment according to the space
available. Later on, when he branches out for himself, he should plan
his shop to got the best working arrangement. Figure 136 shows a
suggested layout for a small shop. Such a layout may have to be
altered because of the size and shape of the shop, and the location of
the windows.
[Fig. 136 Floorplan: layout for a small shop]
As soon as growth of business permits, a shop should have a drive-in,
so that the customer may bring his car off the street. Without a
drive-in all testing to determine what work is necessary will have to
be done at the curb, which is too public for many car owners. A
drive-in is also convenient if a customer leaves his car while his
battery is being repaired. To a certain extent, the advantages of a
drive-in may be secured by having a vacant lot next to the shop, with
a covering of cinders. As soon as possible, however, a shop which is
large enough to have a drive-in should be rented or built.
Figure 137 shows a 24 x 60 shop with space for three cars. The shop
equipment is explained in the table.
Figure 138 shows a 40 x 75 shop with room for six cars and a drive-in
and drive-out. This facilitates the handling of the cars.
Figure 139 shows a 30 x 100 shop in a long and somewhat narrow
building. It also has a drive-in and drive-out.
Another arrangement for the same sized shop as shown in the preceding
illustration is shown in Figure 140. Here the drive-out is at the side
and this layout is, therefore, suitable for a building located on a
corner, or next to an alley.
Figure 141 shows a larger shop, which may be used after the business
has grown considerably.
Figure 142 shows a layout suitable for the largest station.
Somewhere between Figures 136 and 142 is a layout for any service
station. The thing to do is to select the one most suitable for the
size of the business, and to fit local conditions, If a special
building is put up, local conditions are not so important.
If a shop is rented, it may not be possible to follow any of the
layouts shown in Figs. 136 to 142. However, the layout which is best
adapted for the actual shop should be selected as a guide, and the
equipment shown obtained. This should then be arranged as nearly like
the pattern layout as the shop arrangement will permit.
Concerning Light
Light is essential to good work, so you must have plenty of good light
and at the right place. For a light that is needed from one end of a
bench to the other, to look into each individual battery, or to take
the reading of each individual battery, there is nothing better than a
60 Watt tungsten lamp under a good metal shade, dark on outside and
white on inside.
A unique way to hang a light and have it movable from one end of the
bench to the other, is to stretch a wire from one end of the bench to
the other. Steel or copper about 10 or 12 B & S gauge may be used.
Stretch it about four or five feet above top of bench directly above
where the light is most needed. If You have a double charging bench,
stretch the wire directly above middle of bench. Before fastening wire
to support, slip an old fashioned porcelain knob (or an ordinary
thread spool) on the wire. The drop cord is to be tied to this knob or
spool at whatever height you wish the light to hang (a few inches
lower than your head is the right height).
Put the ceiling rosette above center of bench; cut your drop cord long
enough so that you can slide the light from one end of bench to the
other after being attached to rosette. Put vaseline on the wire so the
fumes of gas will not corrode it. This will also make the spool slide
easily. This gives you a movable, flexible light, with which you will
reach any battery on bench for inspection. The work bench light can be
rigged up the same way and a 75 or 100 Watt nitrogen lamp used.
[Fig. 137 Shop layout]
[Fig. 138 Shop layout]
Fig. 137 and 138: A-Receiving Rack. B-Portable Electric Drill, or Hand
Drill. C-Wash Tank, D-Tear Down Bench. E-Hot Water Pan. F-Waiting Rack
(5 Shelves). G-Repair Bench (6 ft. by 2 ft. 3 in.). H-Charging Table
(3 Circuits). I-Electrolyte(10 Gal. Crocks). J-Separator Rack.
K-Generator. L-Switchboard. M-Stock Bins, N-New Batteries, O-Live
storage. P-Sealing Compound. R-Ready Rack (5-Shelves). S-Dry Storage.
(S is not in Fig. 137.)
[Fig. 139, 140 & 141 Various shop layouts]
Fig. 139, 140 and 141: A-Receiving Rack. B-Power Drill. C-Wash Tank.
D-Tear Down Bench. E-Hot Water Pan. F-Waiting Rack (6 Shelves).
G-Repair Bench. H-Charging Table (3 Circuits). I-Electrolyte (10 Gal.
Crocks). J-Separator Rack. K-Generator. L-Switchboard. M-Stock Bins.
N-New Batteries. O-Live storage. P-Sealing Compound. R-Ready Rack
(5-Shelves). S-Dry Storage. T-Torn Down Parts. (O and T in 141, not in
139 and 140.)
[Fig. 142 Shop layout]
Fig. 142: A-Receiving Rack. B-Power Drill. C-Wash Tank. D-Tear Down
Bench. E-Hot Water Pan. F-Waiting Rack (6 Shelves). G-Repair Bench.
H-Charging Table. I-Electrolyte (10 Gal. Crocks). J-Separator Rack.
K-Generator. L-Switchboard. M-Stock Bins. N-New Batteries. O-Live
storage. P-Sealing Compound. R-Ready Rack. S-Dry Storage. T-Torn Down
Parts.
========================================================================
CHAPTER 12.
GENERAL SHOP INSTRUCTIONS.
--------------------------
CHARGING BATTERIES.
The equipment for charging batteries, instructions for building and
wiring charging benches have already been given. What we shall now
discuss is the actual charging. The charge a battery receives on the
charging bench is called a "bench charge."
Battery charging in the service station may be divided into two
general classes:
1. Charging batteries which have run down, but which are otherwise in
good condition, and which do not require repairs.
2. Charging batteries during or after the repair process.
The second class of charging is really a part of the repair process
and will-be described in the chapter on "Rebuilding the Battery."
Charging a battery always consists of sending a direct current through
it, the current entering the battery at the positive terminal and
leaving it at the negative terminal, the charging current, of course,
passing through the battery in the opposite direction to the current
which the battery produces when discharging. When a battery discharges
chemical changes take place by means of which electrical energy is
produced. When a battery is on charge, the charging current causes
chemical changes which are the reverse of those which take place on
discharge and which put the active materials and electrolyte in such a
condition that the battery serves as a source of electricity when
replaced in the car.
Batteries are charged not only in a repair shop but also in garages
which board automobiles, and in car dealers' shops. No matter where a
battery is charged, however, the same steps must be taken and the same
precautions observed.
When a Bench Charge is Necessary:
(a) When a battery runs down on account of the generator on the car
not having a sufficient output, or on account of considerable night
driving being done, or on account of frequent use of the starting
motor, or on account of neglect on the part of the car owner.
(b) Batteries used on cars or trucks without a generator, or batteries
used for Radio work should, of course, be given a bench charge at
regular intervals.
(c) When the specific gravity readings of all cells are below 1.200,
and these readings are within 50 points of each other.
Should the gravity reading of any cell be 50 points lower or higher
than that of the other cells, it is best to make a 15-seconds high
rate discharge test (see page 266) to determine whether the cell is
defective or whether electrolyte has been lost due to flooding caused
by over-filling and has been replaced by water or higher gravity
electrolyte. If any defect shows up during the high rate test, the
battery should be opened for inspection. If no defect shows up, put
the battery on charge.
(d) When the lamps burn dimly while the engine is running.
(e) When the lamps become very dim when the starting switch is closed.
If a battery is tested by turning on the lights and then closing the
starting switch, make sure that there is no short-circuit or ground in
the starting motor circuits. Such trouble will cause a very heavy
current to be drawn from the battery, resulting in a drop in the
voltage of the battery.
(f) When the voltage of the battery has fallen below 1.7 volts per
cell, measured while all the lights are turned on.
(g) When the owner has neglected to add water to the cells regularly,
and the electrolyte has fallen below the tops of the plates.
(h) When a battery has been doped by the addition of electrolyte or
acid instead of water, or when one of the "dope" electrolytes which
are advertised to make old, worn out batteries charge up in a
ridiculously short time and show as much life and power as a new
battery. Use nothing but a mixture of distilled water and sulphuric
acid for electrolyte. The "dope" solutions are not only worthless, but
they damage a battery considerably and shorten its life. Such a
"doped" battery may give high gravity *readings and yet the lamps will
become very dim when the starting motor cranks the car, the voltage
per cell will be low when the lights are burning, or low voltage
readings (1.50 per cell) will be obtained if a high rate discharge
test is made.
Every battery which comes in for any reason whatsoever, or any battery
which is given a bench charge whenever necessary should also be
examined for other defects, such as poorly burned on connectors and
terminals, rotted case, handles pulled off, sealing compound cracked,
or a poor sealing job between the covers and jars, or covers and
posts. A slight leakage of electrolyte through cracks or imperfect
joints between the covers and jars or covers and posts is very often
present without causing any considerable trouble. If any of the other
troubles are found, however, the battery needs repairing.
Arrangement of Batteries on Charging Bench. If a battery comes in
covered with dirt, set it on the wash rack or in the sink and clean it
thoroughly before putting it on charge. In setting the batteries on
the charging bench, place all of them so that the positive terminal is
toward the right as you face the bench. The positive terminal may be
found to be painted red, or may be stamped "+", "P", or "POS". If the
markings on one of the terminals has been scratched or worn off,
examine the other terminal. The negative terminal may be found to be
painted black, or be stamped "-", "N" or "NEG".
If neither terminal is marked, the polarity may be determined with a
voltmeter, or by a cadmium test. To make the voltmeter test, hold the
meter wires on the battery terminals, or the terminals of either end
cell. When the voltmeter pointer moves to the right of the "0" line on
the scale, the wire attached to the "+" terminal of the meter is
touching the positive battery terminal, and the wire attached to the
"-" terminal of the meter is touching the negative battery terminal.
If this test is made with a meter having the "0" line at the center of
the scale, be sure that you know whether the pointer should move to
the left or right of the "0" line when the wire attached to the "+"
meter terminal is touching the positive battery terminal.
Another method of determining which is the positive terminal of the
battery is to use the cadmium test. When a reading of about two volts
is obtained, the prod held on one of the cell terminals is touching
the positive terminal. When a reading of almost zero is obtained, that
is, when the needle of the meter just barely moves from the "0" line,
or when it does not move at all, the prod held on one of the cell
terminals is touching the negative terminal. This test, made while the
battery is on open-circuit, is not a regular cadmium test, but is made
merely to determine the polarity of the battery.
The polarity of the charging line will always be known if the bench is
wired permanently. The positive charging wire should always be to the
right. If a separate switch is used for each battery (Figures 43 and
65), the wire attached to the right side of the switch is positive. If
the batteries are connected together by means of jumpers (Figures 44
and 47), the positive charging wire should be at the right hand end of
the bench as seen when facing the bench. If a constant-potential
charging circuit is used as shown in Figure 48, the positive bus-bar
should be at the top and the neutral in the center, and the negative
at the bottom.
If the polarity of the charging line wires is not known, it may be
determined by a voltmeter, in the same way as the batter-, polarity is
determined. If this is done, care should be taken to use a meter
having a range sufficient to measure the line voltage. If no such
voltmeter is available, a simple test is to fill a tumbler with weak
electrolyte or salt water and insert two wires attached to the line.
The ends of these wires should, of course, be bare for an inch or
more. Hold these wires about an inch apart, with the line alive.
Numerous fine bubbles of gas will collect around the negative wire.
With the polarities of all the batteries known, arrange them so that
all the positive terminals are at the right. Then connect them to the
individual switches (see Figure 43), or connect them together with
jumpers (see Figure 44), being sure to connect the negative of one
battery to the positive of the next. Connect the positive charging
line wire to the positive terminal of the first battery, and the
negative line wire to the negative terminal of the last battery. See
page 105.
With all connections made, and before starting to charge, go over all
the batteries again very carefully. You cannot be too careful in
checking the connections, for if one or more batteries are connected
reversed, they will be charged in the wrong direction, and will most
likely be severely damaged.
As a final check on the connections of the batteries on the line,
measure the total voltage of these batteries and see if the reading is
equal to two times the total number of cells on the line.
Now inspect the electrolyte in each cell. If it is low, add distilled
water to bring the electrolyte one-half inch above the plates. Do not
wait until a battery is charged before adding water. Do it now. Do not
add so much water that the electrolyte comes above the lower end of
the vent tube. This will cause flooding.
Charging, Rate. If you connect batteries of various sizes together on
one circuit, charge at the rate which is normal for the smallest
battery. If the rate used is the normal one for the larger batteries,
the smaller batteries will be overheated and "boiled" to death, or
they may gas so violently as to blow a considerable portion of the
active material from the plates.
It is quite possible to charge 6 and 12 volt batteries in series. The
important point is not to have the total number of cells too high. For
instance, if the 10 battery Tungar is used, ten 6-volt batteries (30
cells), or any combination which gives 30 cells or less may be used.
For instance, five 12-volt batteries (30 cells), or six 6-volt
batteries (18 cells) and two 12-volt batteries (12 cells), or any
other combination totaling 30 cells may be used. The same holds true
for motor-generators.
The charging rate is generally determined by the size of the charging
outfit. The ten battery Tungar should never have its output raised
above 6 amperes. A charging rate of 6 amperes is suitable for all but
the very smallest batteries. In any case, whether you are certain just
what charging rate to use, or not, there are two things which will
guide you, temperature and gassing.
1. Temperature. Have a battery thermometer (Figure 37) on hand, and
measure the temperature of the electrolyte of each cell on the line.
If you note that some particular cell is running hotter than the
others, keep the thermometer in that cell and watch the temperature.
Do not let the temperature rise above 110 degrees Fahrenheit, except
for a very short time. Should the highest of the temperature of the
cells rise above 110 degrees, reduce the charging rate.
2. Gassing. Near the end of a charge and when the specific gravity has
stopped rising, or is rising very slowly, bubbles of gas will rise
from the electrolyte, this being due to the charging current
decomposing the water of the electrolyte into hydrogen and oxygen. If
this gassing is too violent, a considerable amount of active material
will be blown from the plates. Therefore, when this gassing begins,
the charging rate should be reduced, unless the entire charging has
been done at a low rate, say about five amperes.
If gassing begins in any cell soon after the charge is started, or
before the specific gravity has reached its highest point, reduce the
charging rate to eliminate the gassing.
If one battery or one cell shows a high temperature and the others do
not, or begins gassing long before the others do, remove that battery
from the charging line for further investigation and replace it with
another so as not to slow up the charge of the other batteries which
are acting normally.
As long as excessive temperatures and too-early gassing are avoided,
practically any charging rate may be used, especially at the start.
With a constant potential charging set, as shown in Figure 48, the
charge may start at as high a rate as 50 amperes. If this system of
charging is used, the temperature must be watched very carefully and
gassing must be looked for. With the usual series method of charging,
a charge may, in an emergency, be started at 20 amperes or more. As a
general rule do not use a higher rate than 10 amperes. A five ampere
rate is even better, but more time will be required for the charge.
Time Required for a Charge. The time required is not determined by the
clock, but by the battery. Continue the charge until each cell is
gassing freely (not violently) and for five hours after the specific
gravity has stopped rising. The average condition of batteries brought
in for charge permits them to be fully charged in about 48 hours, the
time being determined as stated above. Some batteries may charge fully
in less time, and some may require from four days to a week, depending
entirely upon the condition of the batteries. Do not give any promise
as to when a recharge battery will be ready. No one can tell how long
it will take to charge.
Specific Gravity at the End of the Charge. The specific gravity of the
electrolyte in a fully charged cell should be from 1.280 to 1.300. If
it varies more than 10 points above or below these values, adjust it
by drawing off some of the electrolyte with a hydrometer and adding
water to lower the gravity, or 1.400 acid to raise the gravity. After
adjusting the gravity charge for one hour more.
Battery Voltage at End of Charge. The voltage of a fully charged cell
is from 2.5 to 2.7 when the temperature of the electrolyte is 80
degrees Fahrenheit; 2.4 to 2.6 when the temperature of the electrolyte
is 100 degrees Fahrenheit, and 2.35 to 2.55 volts when the temperature
of the electrolyte is 120 degrees Fahrenheit, and this voltage,
together with hydrometer readings of 1.280-1.300 indicate that the
battery is fully charged.
Just before putting a battery which has been charged into service,
give it a 15 seconds high rate discharge test, see page 266.
Painting. Before returning a battery to the owner wipe it perfectly
clean and dry. Then wipe the covers, terminals, connectors and handles
with a rag wet with ammonia. Next give the case a light coat of black
paint which may be made by mixing lamp black and shellac. This paint
dries in about five minutes and gives a good gloss. The customer may
not believe that you are returning the battery which he brought in but
he will most certainly be pleased with your service and will feel that
if you take such pains with the outside of his battery you will
certainly treat the inside with the same care when repairs are
necessary. The light coat of paint costs very little for one battery,
but may bring you many dollars worth of work.
Level of Electrolyte. During charge the electrolyte will expand, and
will generally flow out on the covers. This need not be wiped off
until the end of the charge. When the electrolyte has cooled after the
battery is taken off charge, it must be about 1/2 inch above the
plates. While the electrolyte is still warm it will stand higher than
this, but it should not be lowered by drawing off some of it, as this
will probably cause it to be below the tops of the plates and
separators when it cools.
TROUBLES
If all goes well, the charging process will take place as described in
the preceding paragraphs. It frequently happens, however, that all
does not go well, and troubles arise. Such troubles generally consist
of the following:
Specific gravity will not rise to 1.280. This may be due to the plates
not taking a full charge, or to water having been used to replace
electrolyte which has been spilled. To determine which of these
conditions exist, make cadmium test (see page 174) on the positives
and negatives, also measure the voltage of each cell. If these tests
indicate that the plates are fully charged (cell voltage 2.5 to 2.7,
Positive-Cadmium 2.4 volts, Negative-Cadmium minus 0.15 to 0.20
volts), you will know that there is not enough acid in the
electrolyte. The thing to do then is to dump out the old electrolyte,
refill with 1.300 electrolyte and continue the charge until the
specific gravity becomes constant. Some adjustment may then have to be
made by drawing off some of the electrolyte with a hydrometer and
adding water to lower the gravity, or 1.400 acid to bring it up.
Remember that specific gravity readings tell you nothing about the
plates, unless it is known that the electrolyte contains the correct
proportions of water and acid. The cadmium test is the test which
tells you directly whether or not the plates are charged and in
charging a battery the aim is to charge the plates, and not merely to
bring the specific gravity to 1.280.
If the specific gravity will not rise to 1.280 and cadmium tests show
that the plates will not take a full charge, then the battery is, of
course, defective in some way. If the battery is an old one, the
negatives are probably somewhat granulated, the positives have
probably lost much of their active material, resulting in a
considerable amount of sediment in the jars, and the separators are
worn out, carbonized, or clogged with sediment. Such a battery should
not be expected to give as good service as a new one, and the best
thing to do if the tests show the battery to be more than half
charged, is to put it back on the car, taking care to explain to the
owner why his battery will not "come up" and telling him that he will
soon need a new battery. Remember that improperly treated separators,
or defective separators will cause poor Negative-Cadmium readings to
be obtained.
If a fairly new battery will not take a full charge, as indicated by
hydrometer readings and cadmium tests, some trouble has developed due
to neglect, abuse, or defect in manufacture. If all cells of a fairly
new battery fail to take a full charge within 48 hours, the battery
has probably been abused by failing to add water regularly, or by
allowing battery to remain in an undercharged condition. Such a
battery should be kept on the line for several days more, and if it
then still will not take a full charge the owner should be told what
the condition of the battery is, and advised to have it opened for
inspection.
If one cell of a battery fails to take a charge, but the other cells
charge satisfactorily, and cadmium tests show that the plates of this
cell are not taking a charge, the cell should be opened for
inspection. If one cell of a battery charges slowly, cut the other
cells out of the line, and charge the low cell in series with the
other batteries on the charging line.
If all cells of a battery, whether new or old, will not take even half
a charge, as indicated by hydrometer readings (1.200), the battery
should be opened for inspection.
If the gravity of a battery on charge begins to rise long before the
voltage rises, and if the gravity rises above 1.300, there is too
great a proportion of acid in the electrolyte. The remedy is to dump
out the electrolyte, refill with pure water and continue the charge at
a lower rate than before, until the specific gravity stops rising.
Then charge for ten hours longer, dump out the water (which has now
become electrolyte by the acid formed by the charging current), refill
with about 1.350 electrolyte and continue the charge, balancing the
gravity if necessary at the end of the charge.
If a battery becomes very hot while on charge at a rate which is not
normally too high for the battery, it indicates that the battery is
badly sulphated, or has a partial short-circuit. Gassing generally
goes with the high temperature.
If you can detect a vinegar-like odor rising from the vent holes, you
may be absolutely sure that the separators used in that battery have
developed acetic acid due to not having received the proper treatment
necessary to prepare them for use in the battery. The electrolyte
should be dumped from such a battery immediately and the battery
should be filled and rinsed with water several times. Then the battery
should be opened without loss of time, to see whether, by removing the
separators and washing the plates thoroughly, the plates may be saved.
If the acetic acid has been present for any length of time, however,
the plates will have been ruined beyond repair, the lead parts being
dissolved by the acid.
If the electrolyte of a battery on charge has a white, milky look,
there may be impurities which cause numerous minute bubbles to form,
such bubbles giving the electrolyte its milky appearance. The milky
appearance may be due to the use of "hard" water in refilling, this
water containing lime.
The electrolyte as seen with the acid of an electric lamp or
flashlight should be perfectly clear and colorless. Any scum,
particles of dirt, any color whatsoever shows that the electrolyte is
impure. This calls for dumping out the electrolyte, filling and
rinsing with pure water, refilling with new electrolyte and putting
the battery back on the charging line. Of course, this may not cause
the battery to charge satisfactorily, which may be due to the troubles
already described.
Should it ever happen that it is impossible to send a current through
a charging circuit go over all the connections to make sure that you
have good contact at each battery terminal, and that there are no
loose inter-cell connectors. If all connections to the batteries are
good, and there are no loose inter-cell connectors, cut out one
battery at a time until you start the current flowing, when you cut
out some particular battery. This battery should then be opened
without further tests, as it is without a doubt in a bad condition.
The conditions which may exist when a battery will not charge, as
shown especially by cadmium tests, are as follows:
(a) The battery may have been allowed to remain in a discharged
condition, or the owner may have neglected to add water, with the
result that the electrolyte did not cover the plates. In either case a
considerable amount of crystallized sulphate will have formed in the
plates. Plates in such a condition will require a charge of about a
week at a low rate and will then have to be discharged and recharged
again. Several such cycles of charge and discharge may be necessary.
It may even be impossible to charge such a battery, no matter how many
cycles of charge and discharge are given. If the owner admits that his
battery has been neglected and allowed to stand idle for a
considerable time, get his permission to open the battery.
(b) The battery may have been overheated by an excessive charging
rate, or by putting it on a car in a sulphated condition. The normal
charging rate of the generator on the car will over heat a sulphated
battery. Overheated plates buckle their lower edges cut through the
separators, causing a short-circuit between plates.
(c) The pockets in the bottoms of the jars may have become filled with
sediment, and the sediment may be short-circuiting the plates.
(d) Impurities may have attacked the plates and changed the active
materials to other substances which do not form a battery. Such plates
may be so badly damaged that they are brittle and crumbled. Acetic
acid from improperly treated separators will dissolve lead very
quickly, and may even cause an open circuit in the cell.
(e) The conditions described in (a), (b), and (c) will permit a
charging current to pass through the battery, but the plates will not
become charged. It is possible, of course, but not probable, that a
condition may exist in which all the plates of one or both groups of a
cell may be broken from the connecting straps, or inter-cell
connectors may be making no contact with the posts. In such a case, it
would be impossible to send a charging current through the battery.
Acetic acid from improperly treated separators, and organic matter
introduced by the use of impure water in refilling will attack the
lead of the plates, especially at the upper surface of the
electrolyte, and may dissolve all the plate lugs from the connecting
straps and cause an open-circuit.
(f) The separators may be soggy and somewhat charred and blackened, or
they may be clogged up with sulphate, and the battery may need new
separators.
(g) The spongy lead may be bulged, or the positives may be buckled.
The active material is then not making good contact with the grids,
and the charging current cannot get at all the sulphate and change it
to active material. The remedy in such a case is to press the
negatives so as to force the active material back into the grids, and
to put in new positives if they are considerably buckled.
(h) One of the numerous "dope" electrolytes which are offered to the
trustful car owner may have been put in the battery. Such "dopes"
might cause very severe damage to the plates. Tell your customers to
avoid using such "dope."
The conditions which may exist when the plates of a battery take a
charge, as indicated by cadmium tests, but the gravity will not come
up to 1.280 are as follows:
(a) There may be considerable sediment in the jars but not enough to
short circuit the plates. If the battery has at some time been in a
sulphated condition and has been charged At too high a rate, the
gassing that resulted will have caused chips of the sulphate to drop
to the bottom of the jars. When this sulphate was formed, some of the
acid was taken from the electrolyte, and if the sulphate drops from
the plates, this amount of acid cannot be recovered no matter how long
the charge is continued. If the owner tells you that his battery has
stood idle for several months at some time, this is a condition which
may exist. The remedy is to wash and press the negatives, wash the
positives, put in new separators, pour out the old electrolyte and
wash out the jars, fill with 1.400 acid, and charge the battery.
(b) Impurities may have used up some of the acid which cannot be
recovered by charging. If the plates are not much damaged the remedy
is the same as for (a). Damaged plates may require renewal.
(c) Electrolyte may have been spilled accidentally and replaced by
water.
(d) Too much water may have been added, with the result that the
expansion of the electrolyte due to a rise in temperature on charge
caused it to overflow. This, of course, resulted in a loss of some of
the acid.
The causes given in (c) and (d) may have resulted in the top of the
battery case being acid-eaten or rotted. The remedy in these two
instances is to draw off some of the electrolyte, add some 1.400 acid
and continue the charge. If plates and separators look good and there
is but little sediment, this is the thing to do.
If Battery will not hold a Charge. If a battery charges properly but
loses its charge in a week or less, as indicated by specific gravity
readings, the following troubles may exist:
(a) Impurities in the cells, due to the use of impure water in the
electrolyte, or in the separators. Some impurities (see page 76) do
not attack the plates, but merely cause self-discharge. The remedy is
to dump out the old electrolyte, rinse the jars with pure water, fill
with new electrolyte of the same gravity as the old and recharge. If
this does not remove impurities, the battery should be opened, the
plates washed, jars cleaned out, new separators put in, and battery
reassembled and charged.
(b) There may be a slow short-circuit, due to defective separators or
excessive amount of sediment. If preliminary treatment in (a) does not
cause battery to hold charge, the opening of battery and subsequent
treatment will remove the cause of the slow short-circuit.
Suggestions
1. Make sure every battery is properly tagged before going on line.
2. Determine as quickly as possible from day to day, those batteries
that will not charge. Call owner and get permission to open up any
such battery and do whatever is necessary to put it in good shape.
3. As soon as a battery charges to 1.280-1.300, the voltage is 2.5-2.7
per cell and the cadmium readings are 2.4 or more for the positives
and -0.15 to -0.20 for the negatives and the gravity voltage and
cadmium readings do not change for five hours, remove it from the line
as finished and replace it with another if possible. Go over your line
at least three times a day and make gravity, temperature, and cadmium
tests.
4. Make a notation, with chalk, of the gravity of each cell each
morning. Do not trust to memory.
5. Remove from the line as soon as possible any battery that has a
leaky cell and neutralize with soda the acid that has leaked out.
6. Batteries that are sloppers, with rotten cases, and without handles
are sick and need a doctor. Go after the owner and get permission to
repair.
7. Keep the bench orderly and clean.
8. Remember that if you have a line only partly full and have other
batteries waiting to be charged you are losing money by not keeping a
full line.
9. Leave the Vent Plugs in When Charging. The atmosphere in many
service stations, where the ventilation is poor, is so filled with
acid fumes that customers object to doing business there.
The owners of these places may not notice these conditions, being used
to it, or rather glory in being able to breathe such air without
coughing or choking, but it certainly does not invite a customer to
linger and spend his money.
The remedy for such a condition is to leave the vent plugs in place on
the batteries that are charging so that the acid spray in the gas from
the battery condenses out as it strikes these plugs and drips back
into the cells, while the gas passes out through the small openings in
the plug.
The plugs need only be screwed into the openings by one turn, or only
set on top of the vent openings to accomplish the result.
This takes no additional time and more than repays for itself in the
saving of rusted tools and improved conditions in the battery room and
surroundings. In charging old Exide batteries, be sure to replace the
vent plugs and turn them to open the air passages which permit the
escape of gases which form under the covers. If you wish to keep these
air passages open without replacing the plugs, which may be done for
convenience, give the valve (see page 21) a quarter turn with a
screwdriver or some other tool.
10. If the electrolyte from a battery rises until it floods over the
top of the jar, it shows that too much water was added when the
battery was put on charge, the water rising to the bottom of the vent
tube, thereby preventing gases formed (except those directly below the
vent hole) from escaping. This gas collects under the covers, and its
pressure forces the electrolyte up into the vent hole and over the top
of the battery. In charging old U.S.L. batteries it is especially
necessary to keep the air vent (see page 20) open to prevent flooding,
since the lower end of the vent tube is normally a little below the
surface of the electrolyte.
Remember, do not have the electrolyte come up to the lower end of the
vent tube.
NOTE: To obtain satisfactory negative cadmium readings, the charging
rate should be high enough to give a cell voltage of 2.5-2.7.
Improperly treated separators, or separators which have been allowed
to become partly dry at any time will make it impossible to obtain
satisfactory negative cadmium readings.
LEAD BURNING (WELDING)
Lead cannot be "burned" in the sense that it bursts into flame as a
piece of paper does when a match is applied to it. If sufficient heat
is applied, the lead will oxidize and feather away into a yellow
looking dust, but it does not burn. The experienced battery man knows
that by "lead burning" is meant the heating of lead to its melting
point, so that two lead surfaces will weld together. This is a welding
and not a "burning" process, and much confusion would be avoided if
the term "lead welding" were used in place of the term "lead burning."
The purpose of welding lead surfaces together is to obtain a joint
which offers very little resistance to the flow of current, it being
absolutely necessary to have as low a resistance as possible in the
starting circuit. Welding also makes joints which are strong
mechanically and which cannot corrode or become loose as bolted
connections do. Some earlier types of starting and lighting batteries
had inter-cell connectors which were bolted to the posts, but these
are no longer used.
The different kinds of lead-burning outfits are listed on page 143 The
oxygen-acetylene and the oxygen-hydrogen flames give extremely high
temperatures and enable you to work fast. Where city gas is available,
the oxygen illuminating gas combination will give a very good flame
which is softer than the oxygen acetylene, oxygen-hydrogen outfits.
Acetylene and compressed air is another good combination.
There are two general classes of lead-welding:
(a) Welding connecting bars, called "cell" connectors, top connectors,
or simply "connectors," to the posts which project up through the cell
covers, and welding terminals to the end posts of a battery.
(b) Welding plates to "straps" to form groups. The straps, of course,
have joined to them the posts which project through the cell covers
and by means of which cells are connected together, and connections
made to the electrical system of the car.
In addition to the above, there are other processes in which a burning
(welding) flame is used:
(c) Post-building, or building posts, which have been drilled or cut
short, up to their original size.
(d) Extending plate lug. If the lug which connects a plate to the
plate strap is too short, due to being broken, or cut too short, the
lug may be extended by melting lead into a suitable iron form placed
around the lug.
(e) Making temporary charging connections between cells by lightly
welding lead strips to the posts so as to connect the cells together.
(f) A lead-burning (welding) flame is also used to dry out the channel
in cell covers before pouring in the sealing compound, in re-melting
sealing compound which has already been poured, so as to assure a
perfect joint between the compound cover and jar, and to give the
compound a smooth glossy finish. These processes are not welding
processes and will not be described here.
General Lead Burning Instructions
Flame. With all the lead burning outfits, it is possible to adjust the
pressures of the gases so as to get extremely hot, medium, and soft
flames. With the oxygen-acetylene, or oxygen-hydrogen flame, each gas
should have a pressure of about two pounds. With the
oxygen-illuminating gas flame, the oxygen should have a pressure of 8
to 10 pounds. The city gas then does not need to have its pressure
increased by means of a pump, the normal pressure (6 to 8 ounces)
being satisfactory.
Various makes of lead-burning outfits are on the market, and the
repairman should choose the one which he likes best; since they all
give good results. All such outfits have means of regulating the
pressures of the gases used. With some the gases are run close to the
burning tip before being mixed, and have an adjusting screw where the
gases mix. Others have a Y shaped mixing valve at some distance from
the burning tip, as shown in Figure 78. Still others have separate
regulating valves for each gas line.
With these adjustments for varying the gas pressure, extremely hot,
hissing flames, or soft flames may be obtained. For the different
welding jobs, the following flames are suitable:
1. A sharp, hissing flame, having a very high temperature is the one
most suitable for the first stage in welding terminals and connectors
to the posts.
2. A medium flame with less of a hiss is suitable for welding plates
to strips and lengthening plate lugs.
3. A soft flame which is just beginning to hiss is best for the
finishing of the weld between the posts and terminals or connectors.
This sort of a flame is also used for finishing a sealing job, drying
out the cover channels before sealing, and so on.
In adjusting the burning flame, 4 the oxygen is turned off entirely, a
smoky yellow flame is obtained. Such a flame gives but little heat. As
the oxygen is gradually turned on the flame becomes less smoky and
begins to assume a blue tinge. It will also be noticed that a sort of
a greenish cone forms in the center portion of the flame, with the
base of the cone at the torch and the tip pointed away from the torch.
At first this inner-cone is long and of almost the same color as the
outer portion of the flame. As the oxygen pressure is increased, this
center cone becomes shorter and of a more vivid color, and its tip
begins to whip about. When the flame is at its highest temperature it
will produce a hissing sound and the inner cone will be short and
bright. With a softer flame, which has a temperature suitable for
welding plates to a strap, the inner cone will be longer and less
vivid, and the hissing will be greatly diminished.
The temperature of the different parts of the flame varies
considerably, the hottest part being just beyond the end of the inner
cone. Experience with the particular welding outfit used will soon
show how far the tip of the torch should be held from the lead to be
melted.
Cleanliness. Lead surfaces which are to be welded together must be
absolutely free from dirt. Lead and dirt will not mix, and the dirt
will float on top of the lead. Therefore, before trying to do any lead
welding, clean the surfaces which are to be joined. The upper ends of
plate lugs may be cleaned with a flat file, knife., or wire brush. The
posts and inter-cell connectors should be cleaned with a knife, steel
wire brush, or triangular scraper. Do not clean the surfaces and then
wait a long time before doing the lead burning. The lead may begin to
oxidize if this is done and make it difficult to do a good job.
The surfaces which are to be welded together should also be dry. If
there is a small hole in the top of a post which is to be welded to a
connector or terminal, and this hole contains acid, a shower of hot
lead may be thrown up by the acid, with possible injury to the
operator.
Do not try to save time by attempting to weld dirty or wet lead
surfaces, because time cannot be saved by doing so, and you run the
risk of being injured if hot lead is thrown into your face. Remove
absolutely every speck of dirt--you will soon learn that it is the
only way to do a good job.
Safety Precautions. Remove the vent plugs and blow down through the
vent holes to remove any gases which may have collected above the
surface of the electrolyte. An explosion may result if this is not
done. To protect the rubber covers, you may cover the whole top of the
battery except the part at which the welding is to be done, with a
large piece of burlap or a towel which has been soaked in water. The
parts covered by the cloth must be dried thoroughly if any welding on
them. Instead of using a wet cloth, a strip of asbestos may be laid
over the vent holes, or a small square of asbestos may be laid over
each vent hole.
Burning on the Cell Connectors and Terminals
Have the posts perfectly clean and free from acid. Clean the tops,
bottoms and sides of the connectors with a wire brush, Figure 143.
Finish the top surfaces with a coarse file, Figure 144. With a pocket
knife clean the inside surfaces of the connector holes. Place the
connectors and terminals in their proper positions on the posts, and
with a short length of a two by two, two by one, or two by four wood
pound them snugly in position, Figure 145. Be sure that the connectors
are perfectly level and that the connectors are in the correct
position as required on the car on which the battery is to be used.
The top of the post should not come flush with the top of the
connector. Note, from Figure 146, that the connector has a double
taper, and that the lower tapered surface is not welded to the post.
If the post has been built up too high it should be cut down with a
pair of end cutting nippers so that the entire length of the upper
taper in the connector is in plain sight when the connector is put in
position on the post. This is shown in Figure 146. With the connectors
in place, and before welding them to the posts, measure the voltage of
the whole battery to be sure that the cells are properly connected, as
shown by the voltage reading being equal to two times the number of
cells. If one cell has been reversed, as shown by a lower voltage
reading now is the time to correct the mistake.
[Fig. 143 Brushing connector before burning in]
[Fig. 144 Rasping connector before burning in]
The connectors and terminals are now ready to be welded to the posts.
Before bringing any flame near the battery be sure that you have blown
out any gas which may have collected under the covers. Then cover the
vents with asbestos or a wet cloth as already described. You will
need strips of burning lead, such as those made in the burning lead
mould described on page 164.
Use a hot, hissing flame for the first stage. With the flame properly
adjusted, hold it straight above the post, and do not run it across
the top of the battery. Now bring the flame straight down over the
center of the post, holding it so that the end of the inner cone of
the flame is a short distance above the post. When the center of the
post begins to melt, move the flame outward with a circular motion to
gradually melt the whole top of the post, and to melt the inner
surface of the hole in the connector. Then bring the lower end of your
burning lead strip close to and over the center of the hole, and melt
in the lead, being sure to keep the top of the post and the inner
surface of the hole in the connector melted so that the lead you are
melting in will flow together and unite. Melt in lead until it comes
up flush with the upper surface of the connector. Then remove the
flame. This completes the first stage of the welding process. Now
repeat the above operation for each post and terminal.
[Fig. 145 Leveling top connectors before burning in]
It is essential that the top of the post and the inner surface of the
hole in the connector be kept melted as long as you are running in
lead from the strip of burning lead. This is necessary to have all
parts fuse together thoroughly. If you allow the top of the post, or
the inner surface of the hole in the connector to chill slightly while
you are feeding in the lead, the parts will not fuse, and the result
will be a poor Joint, which will heat up and possibly reduce the
current obtained from the battery when the starting switch is closed.
This reduction may prevent the starting motor from developing
sufficient torque to crank the engine.
When the joint cools, the lead will shrink slightly over the center of
the posts. To finish the welding, this lead is to be built up flush or
slightly higher than the connector. Brush the tops of the post and
connector thoroughly with a wire brush to remove any dirt which may
have been floating in the lead. (Dirt always floats on top of the
lead.) Soften the burning flame so that it is just barely beginning to
hiss. Bring the flame down over the center of the post. When this
begins to melt, move the flame outward with a circular motion until
the whole top of post and connector begins to melt and fuse. If
necessary run in some lead from the burning lead strip. When the post
and connector are fused, clear to the outer edge of the connector,
raise the flame straight up from the work.
[Fig. 146 Connector in position on post for for welding to post.
Surfaces A-B are not welded together]
You will save time by doing the first stage of the burning on all
posts first, and then finish all of them. This is quicker than trying
to complete both stages of burning on each post before going to the
next post. The object in the finishing stage is to melt a thin layer
of the top of post and connector, not melting deep enough to have the
outer edge of the connector melt and allow the lead to run off. All
this must be done carefully and dexterously to do a first-class job,
and you must keep the flame moving around over the top and not hold it
in any one place for ally length of time, so as not to melt too deep,
or to melt the outer edge and allow the lead to run off and spoil the
job. Sometimes the whole mass becomes too hot and the top cannot be
made smooth with the flame. If this occurs wait until the connector
cools, soften the flame, and try again. Figure 147 shows the welding
completed.
[Fig. 147 Connectors "burned" to posts]
Burning Plates to Strap and Post
First clean all the surfaces which are to be welded together. Take
your time in doing this because you cannot weld dirty surfaces
together.
Plates which compose a group are welded to a "strap" to which a post
is attached, as shown in Figure 5. The straps shown in Figure 5 are
new ones, as made in the factory. Plate lugs are set in the notches in
the straps and each one burned in separately. In using old straps from
a defective group, it is best to cut the strap close to the post, thus
separating all the plates from the post in one operation, as was done
with the post shown in Figure 96. If only one or two plates are to be
burned on, they are broken or cut off and slots cut in the strap to
receive the lugs of the new plates, as shown in Figures 148 and 149.
[Fig. 148 Sawing slot in plate strap]
Set the plates in a plate burning rack, as shown in Figure 96, placing
the adjustable form around the lugs and strap as shown in this figure.
Be sure to set the post straight, so that the covers will fit. A good
thing is to try a cover over the post to see that the post is set up
properly. The post must, of course, be perpendicular to the tops of
the plates. If the slotted plate strap shown in Figure 5 is used, or
if one or two plates have been cut off, melt the top of the lug of one
of the plates which are to be burned oil, and the surfaces of the
strap to which the plate is to be welded. Melt in lead from a
burning-lead strip to bring the metal up flush with the surface of the
strap. Proceed with each plate which is to be burned on.
If all the plates have been sawed from the strap, leaving the post
with a short section of the strap attached, as shown in Figure 96,
melt the edge of the strap, and the top of one or two of the end plate
lugs and run in lead from the burning strip to make a good joint.
Proceed in this way until all the lugs are joined to the strap and
then run the flame over the top of the entire strap to make a smooth
uniform weld. Be sure to have the lower edge of the strap fuse with
the plate lugs and then run in lead to build the strap up to the
proper thickness. Raise the flame occasionally to see that all parts
are fusing thoroughly and to prevent too rapid heating.
[Fig. 149 Slotting saw, a group with two plates cut off, and
slots in strap for new plates]
When enough lead has been run in to build the strap tip to the correct
thickness and the plate lugs are thoroughly fused with the strap,
raise the flame straight up from the work. Allow the lead to "set" and
then remove the adjustable form and lift the group from the burning
rack. Turn the group up-side-down and examine the bottom of the strap
for lead which ran down the lugs during the welding process. Cut off
any such lead with a saw, as it may cause a short-circuit when the
plates are meshed with the other group.
Post Building
In drilling down through the inter-cell connectors to separate them
from the posts in opening a battery, the posts may be drilled too
short. In reassembling the battery it is then necessary to build the
posts up to their original height. This is done with the aid of
post-builders, shown in Figure 100.
Clean the stub of the post thoroughly and also clean the inside of the
post builder. Then set the post builder carefully over the stub post,
so that the upper surface of the post builder is parallel to the upper
surface of the plate strap. The built up post will then be
perpendicular to the surface of the strap, which is necessary, in
order to have the covers and connectors fit properly.
With the post builder set properly adjust the burning torch to get a
sharp, hissing flame. Bring the flame straight down on the center of
the post stub. When the center of the post stub begins to melt, move
the flame outward with a circular motion until the whole top of the
stub begins to melt. Then run in lead from a burning lead strip,
Figure 101, at the same time keeping the flame moving around on the
top of the post to insure a good weld. In this way build up the post
until the lead comes up to the top of the post builder. Then lift the
flame straight up from the post. Allow the lead to set, and then
remove the post builder, grasping it with a pair of gas or combination
pliers and turn the post builder around to loosen it.