Electrolyte Level Adjustment

TM 11-6140-203-14-4&P

5. If batteries are discharged at a

low state of charge or in a discharged condition.

higher rate than give in (1) above, refer to paragraph 4-

When the battery is recharged, the electrolyte

level rises and reaches its maximum height at

14 applicable capacity at the specific rate.

full charge. Ideally the electrolyte level should be

6 If all cells are 1 volt or greater, stop

checked on a fully charged battery that has been

discharging and proceed to final charge.

at rest for a minimum of 30 minutes to a

(2) Final charge. Perform final charge in

accordance with (a), (b) or {c} below depending on

maximum of 2 hours before checking the

electrolyte level. If the 2-hour time is exceeded

equipment available.

before the level of the electrolyte is checked, the

(a) The ANIUSM-432 will recharge the

battery must be brought back up to full charge

battery for 1 hour and then shut off. Cell voltage checks

state and allow to rest again before performing

and electrolyte level adjustments should then be made

the check. The maximum rest time must be

before the battery is placed in service.

strictly adhered to. After the battery has been

(b) The RF80GT will recharge most

removed from the battery charger, it will

batteries in one hour and then shutoff providing a Battery

discharge gases trapped between the separators

OK indication if more than 60 minutes was obtained on

and plates during the rest period. As this

the performance test.

Cell voltage checks and

progresses, electrolyte solution is absorbed into

electrolyte level adjustments should then be made before

the battery plates in place of the gases. If the

the battery is placed in service Do not start final charge if

battery has rested longer than the maximum

battery temperature exceeds 104' F for cellophane

period of time, absorption could bring the

separated batteries, or 120' F for Permion or Celgard

electrolyte level to the point that inspection would

separated ones. Wait until battery has cooled to ambient

indicate that more should be added. Correction

temperature before finishing change and placing in

of the electrolyte level under these conditions

service.

could overfill the cell and cause spewing when

the battery is brought to a full charge while

current charging should be performed in accordance with

installed in the equipment for service. The

paragraphs 5-5f(3) of f(4), respectively.

correct level of electrolyte is 1/4 inch above the

(3) Battery rest. Allow battery to rest for 30

top of the plates of a fully charge cell that has

minutes before adjusting electrolyte level (para 5-5).

been at rest as specified paragraph 5-4g. The

(4) Electrical leakage.

Perform electrical

procedure for checking the electrolyte level is

leakage test 95 specified in paragraph 4-10.

exactly the opposite of that for lead-acid

batteries in which the electrolyte level is adjusted

5-5.

Electrolyte Level Adjustment

by adding water before placing the battery on

CAUTION

charge, or whenever the electrolyte level is low.

For batteries requiring electrolyte adjustment, be

The maximum electrolyte level for a nickel-

sure to perform the charging procedures given in

cadmium battery is one-fourth inch above the top

paragraph 5-4f first. These procedures must be

of the plates. Perform the following procedures

followed to prevent overfilling cells. Overfilling

for electrolyte adjustments:

will cause spewage of electrolyte resulting in

a. Before using the syringe, if necessary, modify it

damage to the battery. Do not adjust electrolyte

as follows:

level after a battery has discharged. The correct

(1) Use a sharp pin that has been heated with

electrolyte level cannot be determined when the

a flame to pierce the stem of the syringe one-fourth inch

battery has been discharged. Conversely, never

from the bottom of the stem (A, fig. 5-2).

allow electrolyte to fall below the top of the plates

(2) Let the pin remain in the. stem for 2 or 3

when battery is in a charged condition. Low

minutes and then withdraw the pin slowly from the stem.

electrolyte level in the charged condition will

b. Remove the fillercaps with the nylon wrench.

cause the cells to heat up, resulting in their

destruction.

NOTES

An inherent characteristic of nickelcadmium

battery cells is that the electrolyte is absorbed

within the plates and separators to a point where

it is not visible from the top of the cells when at a

5-6