Slow Out-Of-Vehicle Charging

TM 10-3930-644-14 & P

10. Slow Out-Of-Vehicle Charging

charger which has provision for finishing the

charging cycle at a low rate will permit the

A slow charger is a device which will supply

battery to become fully charged if sufficient time

current to the battery at a low charging rate

is allowed.

which is necessary in order to fully charge it.

Due to the low rate during slow charging, plenty

C. INSTALLATION

of time must be allowed. Charge periods of 24

hours or more are often required.

The following points are Important to properly install a

battery.

11. Full Charging for Hydrometer Test

1. Be sure that the battery tray is clean and that the

To fully charge a battery, the current input to the

battery rests level when installed.

battery should be adjusted to a charging rate

equivalent to 7% of the 20 hour rate of the

2. Tighten the hold-down evenly until snug. Do not

battery.

draw down tight enough to distort or crack

battery case.

Example: A 100 ampere hour battery should be

slow charged at 7 amperes. (7% of 100 AH = 7

3. Be sure the cables are in good condition and the

amperes charge rate.) If several batteries of

terminal clamps are clean.

Grease battery

different sizes are charged in series, the

terminals lightly before attaching cable clamps.

charging rate is determined by the battery with

Make sure the ground cable is clean and tight.

the lowest ampere hour rating. If the ampere-

hour capacity of a battery cannot be determined,

4. Check polarity to be sure battery is not reversed

charge it at S amperes.

with respect to the generating system.

Charging should be continued until the battery is

CAUTION

fully charged. This is indicated when all cell

DO NOT POLARIZE ALTERNATOR!

gravities do not increase when checked with a

hydrometer at three intervals of one hour and all

5. Connect "grounded" terminal of the battery last

cells are gassing freely. When fully charged, all

to avoid short circuits which will damage the

of the plate material in the battery has been

battery.

reconverted into active material.

12. Slow Charging with Fast Charger

Some chargers are equipped to charge at either

a high or low rate, a

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