The battery is charged with a current of 5.5 A with the plugs turned out. Charging is carried out before the onset of abundant gas evolution and the achievement of a constant voltage and electrolyte density for 3 hours. The density of the electrolyte of a charged battery at 25°C must comply with the data in Table 7-5 for each climatic region.
Table 7-5. Electrolyte density at 25 C, g/cm
When charging the battery, it is necessary to periodically check the temperature of the electrolyte and not allow it to rise above 40°C. If the temperature reaches 40°C, then reduce the charging current by half or interrupt charging and cool the battery down to 27°C.
Charging stops when abundant gas evolution begins in all battery cells, and the voltage and density of the electrolyte during the last three measurements (produced after 1 hour) will remain constant.
If at the end of charging the density of the electrolyte (determined taking into account the temperature correction) differs from the specified one, correct it. With increased density, remove some of the electrolyte and add distilled water. If the density of the electrolyte is below normal, then after removing it from the cell, add electrolyte of increased density (1.4 g/cm3).
After adjusting the density of the electrolyte, continue charging the battery for another 30 minutes to mix the electrolyte. Then disconnect the battery and after 30 minutes measure its level in all elements. If the electrolyte level is below normal, then add electrolyte with a density corresponding to the given climatic region (see table. 7-5). If the electrolyte level is above normal, remove its excess with a rubber bulb.