The battery is charged with a current of 5.5 A with the plugs removed. Charging is carried out until abundant gas evolution begins and the voltage and density of the electrolyte remain constant for 3 hours. The density of the electrolyte of a charged battery at 25°C should correspond to the data in the table. 10.2 for each climatic region.
When charging the battery, periodically check the electrolyte temperature and do not allow it to rise above +40°C. When the temperature reaches +40°C, reduce the charging current by half or interrupt charging and cool the battery to +27°C.
Charging is stopped when abundant gas emission begins from all battery elements, and the voltage and density of the electrolyte during the last three measurements (carried out 1 hour after disconnecting the battery) will remain constant.
If at the end of charging the density of the electrolyte (determined taking into account the temperature correction) differs from that indicated in the table. 10.2, correct it. If the density is high, remove some of the electrolyte and add distilled water. If the density of the electrolyte is below the norm, remove it from the element and add electrolyte of increased density (1.4 g/cm³).
After adjusting the electrolyte density, continue charging the battery for another 30 minutes to mix the electrolyte. Then disconnect the battery and after 30 minutes measure the electrolyte level in all elements. If the electrolyte level is below the norm, add electrolyte with a density corresponding to the given climate zone (see table 10.2). If the electrolyte level is above normal, remove excess electrolyte with a rubber bulb.
Table 10.2. Electrolyte density at 25°C, g/cm³
