The battery should always be kept clean and dry. Traces of electrolyte on the surface of the battery must be removed with a clean rag soaked in a 10% solution of ammonia or baking soda. It is necessary to regularly monitor the cleanliness of the ventilation holes in the plugs.
Checking the electrolyte level
The electrolyte level must be between the marks «MIN» and «MAX», applied to the translucent battery case. If there are no marks, then the level should be 5...10 mm above the edge of the separators and not rise above the lower edge of the indicator 7 (see fig. 96). During operation of the battery, the electrolyte level gradually decreases, as the water that is part of it evaporates. To restore the electrolyte level, it is necessary to add only distilled water. If it is determined that the cause of the low level is sloshing, then it is necessary to add electrolyte of the same density as that remaining in the battery cell. If the level is above normal, then the electrolyte should be sucked out with a rubber bulb with an ebonite tip.
Checking the degree of discharge of the battery
To determine the degree of discharge with a car hydrometer, the density of the electrolyte is measured. If the battery is discharged by more than 25% in winter and 50% in summer, it must be removed from the vehicle and recharged. During the density measurement, make sure that no drops of electrolyte containing sulfuric acid, which causes corrosion, current leakage, etc., fall on the surface of the battery, body and other parts from the pipette. The degree of battery discharge is determined by tab. 4.
The density of the electrolyte depends on the temperature. With a change in it for every 15°C, the density changes by approximately 0.01 g / cm3. Therefore, if the electrolyte temperature is higher or lower than +25°C, then it is necessary to add to the hydrometer reading or subtract from it the temperature correction indicated in Table. 5.
To avoid erroneous results, electrolyte density should not be measured:
- if its level does not correspond to the norm; if the electrolyte is too hot or cold (optimal electrolyte temperature when measuring density 15...25°С);
- after adding distilled water. Wait until the electrolyte is mixed (if the battery is low, this may even take several hours);
- after a few starts. It is necessary to wait until a uniform density of the electrolyte in the battery cell is established;
- at «boiling» electrolyte. It is necessary to wait until the bubbles in the electrolyte collected in the hydrometer 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 a strong heating of the battery in operation (more than 10°C above ambient temperature) or electrolyte density in different battery cells differs by more than 0.2 g/cm3, then it is necessary to recharge the battery with a current of 2... 3 A for 24 hours. If, after no charge, the battery voltage is less than 12 V, then it is unusable.
If, when measuring the density of the electrolyte, it is found that it is excessively high (1.3 g/cm3 and higher), then it is brought to the norm, as indicated above.
Battery charge
The battery removed from the vehicle must be carefully cleaned, especially its upper part, and the electrolyte level checked. 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 remains unchanged.
At the end of the charge, the density of the electrolyte sometimes differs from the norm. In this case, bring it to the recommended value. With increased density, take a part of the electrolyte from the battery cell with a rubber pear with an ebonite tip, and then add distilled water, wait until the electrolyte is mixed, and measure the density again. If the density of the electrolyte is below normal, then, having partially removed it from the cell, add an electrolyte of increased density (1.40 g/cm3).
When charging, it is necessary to periodically check the temperature of the electrolyte. The initial temperature should not exceed +27°C. In the process of charging, it is necessary to ensure that the temperature does not rise above + 40°C. When it is reached, reduce the charging current by half or interrupt the charge for a while and cool the battery to + 20°C.