Cleaning Storage Battery

TM 11-6140-224-13&P

20F to 65 minutes at -250F. Figure 4-2 is a typical curve showing the on-off heating characteristics at a fixed cranking

speed.

After the battery has been completely charged the heater load will still be maintained on the G-76/G generator until

the battery temperature reaches approximately 500F. It is therefore difficult to determine when cranking can be stopped;

however, if cranking has continued continuously at 2 amperes or above for the times given previously and the 2 ampere

light cannot be lit after 3 minutes of additional cranking, then the battery is fully charged.

4-12. Discharge

The battery is designed to be discharged at currents up to 10 amperes Currents in excess of 15 arnperes or temporary

shorting of output loads will cause the battery fuse to blow. The battery is equipped with an automatic discharge cutoff

which will stop the discharge of the battery when its voltage falls to 20 volts. The battery cannot be discharged again and

will read 0 volts at the output terminals unless it is exposed to an input voltage greater than 28 volts, which will reset the

latch relay contacts. The battery is capable of 500 or more charge-discharge cycles however. operating, at temperatures

above 120F tends to degrade performance. Reduced performance is obtained at temperatures of -25F to -40F

particularly for low currents associate,? with the radio receive loads.

4-13. Storage

The battery is capable of extended storage (up to 5 years) if temperature excursions above 120F are limited. Charge

retention in storage is dependent on temperature. Capacity loss will average approximately 4% per day at 120F, 1% per

day at 70F, and 0.3% per day at 30F.

4-14. Cleaning Storage Battery

Normal cleaning of nickel-cadmium battery involves removing the battery box cover. Clean battery by removing dirt and

corrosion from connectors and other visible hardware. Do not use solvents for cleaning the storage battery.

4-15. Organizational Repair of Battery, Storage BB-542/U

Repair of the storage battery at the organizational maintenance category consists of replacing fuses and dust caps,

cleaning obvious corrosion and dirt, and tightening loose screws.

WARNING

The storage battery is charged and will cause bodily injury and equipment

damage if the cells or internal connections are short-circuited, or if the fuse is

bypassed and the external connectors are short-circuited.

Removal and Replacement of Dust Cap.

(1) Remove the screw that holds the dust cap keeper chain to the battery.

(2) Place new dust cap in position on connector.

(3) Secure the dust cap by inserting the screw and tightening it to the battery.

b. Removal and Replacement of Fuse.

(1) Disconnect all external loads.

(2) Remove defective fuse from fuseholder.

(3) Examine fuseholder contacts for dirt or corrosion.

(4) Remove spare fuse from holder.

(5) Place spare fuse in fuseholder.

c. Tightening Screws and Nuts. The only screws and nuts that should be tightened by the operator

are those holding the MS3112E-14-55S connector and the four screws holding the control module to the battery.

4-16. Organizational Troubleshooting Chart

The organizational troubleshooting chart, Table 4-2, will aid in isolating troubles that occur in the BB-542/U.

4-5