Table 7-3. Electrolyte density at 25°С, g/cm3
If the battery is discharged by more than 25% in winter and 50% in summer, remove it from the vehicle and recharge it.
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, on the body and others flying from the pipette.
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 add to the hydrometer reading or subtract the temperature correction from it:
Electrolyte temperature,°С | Correction, g/cm3 |
-40 to -26 | -0,04 |
-25 to -11 | -0,03 |
-10 to +4 | -0,02 |
from +5 to +19 | -0,01 |
from +20 to +30 | 0,00 |
from +31 to +45 | +0,01 |
To avoid erroneous results, do not measure the density of the electrolyte:
- if its level does not correspond to the norm;
- if the electrolyte is too hot or cold; optimum electrolysis temperature when measuring density 15-25°С;
- after topping up with distilled water, wait until the electrolyte moves; if the battery is low, this may even take several hours;
- after turning on the starter several times, wait until a uniform dense! b electrolyte in the battery cell is established;
- at «boiling» electrolyte 4 should wait until the bubbles in the electrolyte collected in the hydrometer pipette rise to the surface.
If the electrolysis 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 in these cases, 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 unusable.
If, when measuring the density of the electrolyte, it is found that it is excessively high (1.3 g/cm3 and higher), then bring it to the norm, as indicated below.