Checking the electrolyte level
The electrolyte level should be 5-10 mm above the upper edge of the separators and not rise above the lower edge of the filler neck. During battery operation, the electrolyte level gradually decreases as the water contained in it evaporates. To restore the electrolyte level, add distilled water.
If it is definitely established that the cause of the low level is splashing, then it is necessary to add electrolyte of the same density as that remaining in the battery element. If the level is above the norm, then the electrolyte must be collected with a rubber bulb.
Checking the battery level
To determine the degree of discharge, measure the density of the electrolyte with a car dynamometer and compare it with the data in Table 12. If the battery is discharged by more than 25% in winter and 50% in summer, it should be removed from the car and recharged.
The density of the electrolyte depends on the temperature. With a change in the latter by every 15°C, the density changes by approximately 0.01 g/cm³. Therefore, if the electrolyte temperature differs from 25°C, then a temperature correction should be added or subtracted from the densimeter readings:
To avoid getting erroneous results, do not measure the electrolyte density in the following cases:
- if its level does not correspond to the norm;
- when the electrolyte is too hot or cold. The optimum temperature of the electrolyte when measuring the density is 15-25°C;
- immediately after adding distilled water. You should wait until the electrolyte mixes. If the battery is discharged, this may take even several hours;
- after several starts. It is necessary to wait until the electrolyte density in the battery cells is uniform;
- with "boiling" electrolyte. You should wait until the bubbles in the electrolyte collected in the densimeter pipette rise to the surface.
If, when measuring the specific gravity of the electrolyte, it is found to be excessively high (1.3 g/cm³ and above), then it is necessary to remove some of the electrolyte from the element and add distilled water instead, wait until the electrolyte mixes, and measure the density again.
If the density of the electrolyte is low, then after removing it from the element, add electrolyte with a density of 1.40 g/cm³.
When measuring the density, make sure that drops of electrolyte containing sulfuric acid, which causes corrosion, current leakage, etc., do not fall from the pipette onto the surface of the battery, the body and other parts.
Battery charge
Carefully clean the battery removed from the car, especially its upper part, check the electrolyte level and bring it to the norm. The battery is charged with a current of 5.5 A with the plugs unscrewed. Charging stops when abundant gas emission begins in all battery compartments, and the voltage and density of the electrolyte during the last three measurements (carried out every 1 hour) will remain constant. The density of the electrolyte of a charged battery at 25°C should correspond to the data in Table 12.
When charging the battery, periodically check the electrolyte temperature and do not allow it to rise above 40°C. If the temperature reaches 40°C, reduce the charging current by half or interrupt charging and cool the battery to 27°C.
If at the end of the charge the density of the electrolyte (determined taking into account the temperature correction) differs from that specified in Table 12, then correct it. Then continue charging the battery for another 30 minutes to mix the electrolyte.
Disconnect the battery and measure its level in all elements after 30 minutes. If the electrolyte level differs from the norm, then bring it to the recommended value, as indicated earlier.