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, only distilled water should be added.
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 with an ebonite tip.
Checking the battery level
To determine the degree of discharge, measure the density of the electrolyte with an automotive densimeter and compare it with the data in Table 23. If the battery is discharged by 25% in winter or 50% in summer, it should be removed from the car and recharged.
When measuring the density, make sure that no electrolyte containing sulfuric acid, which causes corrosion, current leakage, etc., drips onto the surface of the battery, body, or other parts.
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. the temperature correction should be added or subtracted from the densimeter readings:
To avoid getting erroneous results, do not measure the density of the electrolyte 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;
- 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. You should wait until the electrolyte density in the battery element is uniform;
- with "boiling" electrolyte. You should wait until the bubbles in the electrolyte collected in the densimeter pipette rise to the surface.
If the electrolyte density is too low (less than 1.22 g/cm³) and at the same time there is strong heating of the battery during operation (more than 10°C above the ambient temperature) or the density of the electrolyte in different elements of the battery differs by more than 0.2 g/cm³, then in these cases it is necessary to recharge the battery with a current of 2-3 A for 24 hours. If after recharging the battery voltage is less than 12 V, then it is unsuitable for operation.
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 bring it up to the norm, as indicated below.
Charging the battery. After removing the battery from the car, it is necessary to carefully clean it, especially its upper part, and check the electrolyte level. The battery is charged with a current of 5.5 A for several hours until the voltage becomes constant and the density of the electrolyte unchanged. At the end of the charge, the density of the electrolyte sometimes differs from the norm. In this case, it is brought to the recommended value. If the density of the electrolyte is higher than normal, then part of the electrolyte should be sucked out of the element, distilled water should be added instead, wait until the electrolyte mixes, and the density should be measured again. If the density of the electrolyte is low, then after sucking it out of the element, add electrolyte with a density of 1.40 g/cm³.