TM 10-6140-200-14
b. Therefore a cell or battery must first be given an
with a new jar and cover it is very important to adhere to
the following procedure to obtain an effective seal:
equalizing charge as described in Paragraph 2-10c. Never
make a gravity adjustment on a cell which does not gas
vigorously while on charge.
(1) Use epoxy only on rubber jars and covers.
(2) Thoroughly clean cover and jar sealing areas first
with xylol (xylene), then with isopropyl alcohol using a
cell, corrected for temperature, is lower than normal, it
separate cleaning cloth for each.
should be adjusted in the following manner:
(3) Caulk bottom of seal groove with glass cord. Tamp
(1) Put battery back on charge at the finish rate until
corners in. Make overlap small. Do not use warm compound
cells are actively gassing to provide proper mixing.
with epoxy.
(2) Remove electrolyte from the low reading cells until
(4) Use special epoxy sealant as recommended by the
level reaches the separator protector.
battery manufacturer. Follow instructions provided. This is
available in kit form.
(3) Slowly add 1.400 specific gravity sulfuric acid to the
cell while it is still gassing.
(5) Apply epoxy in two pours. Second pour within
two hours after first pour. Fill to top of jar. Do not overfill.
(4) Wait 15 to 20 minutes for the added acid to become
thoroughly mixed and then read the specific gravity. If it is
still low, repeat the process until gravity is normal. As a
(6) Pressure test seal after three hours or more from
guide, every 1/4" of electrolyte that has been removed and
time of pouring. Pressure test to 1.5 P.S.I. for 10 seconds.
replaced by 1.400 acid will cause the specific gravity to rise
d. Heat Bonded Plastic Cover to Jar Seal and Lead
4 to 5 points (.004 to .005).
Bushing Design. This is the newest of the sealing systems
used with motive power batteries. To disassemble a cell of
d. If the corrected specific gravity of any cell is higher than
this design also requires that the jar be cut and both jar and
normal, proceed as follows:
cover be replaced. The seal between jar and cover is, in
effect, a plastic weld. It can only be used with jars and
(1) While the battery is gassing on charge, withdraw from
covers made from the identical plastic molding material.
the cell a small amount of electrolyte and replace with
approved water.
e. Since special techniques must be used when resealing
these covers, the battery manufacturer recommends that
(2) Repeat, if necessary, at 20 to 30 minute intervals
these cover to jar seals not be attempted in the field.
until the desired reading is obtained. Every 1/4" of
Manufacturers instructions request that such repairs be
electrolyte, which is replaced by water, will cause the
made in their service stations only.
specific gravity of the cell electrolyte to drop 4 to 5 points
(.004 to .005).
3-12. Adjusting Specific Gravity of Electrolyte
WARNING
a. Fully charged cells usually operate at a specific gravity
between 1.275 and 1.295. Normally it should never be
Never add acid with a specific gravity higher
necessary to adjust the gravity, but upsets, jar breakage,
than 1.400. Stronger acid could permanently
additions of too much water and careless use of hydrometer
damage the cell. When mixing or cutting acid,
can result in electrolyte loss and possible reductions of
always add the acid to the water. NEVER pour
water into acid. A violent reaction could result
battery capacity. Lost electrolyte must be replaced but
only after it has been determined that charging will not
which might cause personal injury. When work-
restore the gravity to normal when at the recommended
ing with acid always use a face shield or goggles,
rubber gloves and an acid resistant apron.
level.
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