Check electrolyte density in the rechargeable battery every 3 month.
Check is made by the areometer. When determining density of electrolyte consider its temperature. At a temperature of electrolyte below 15 °C on each 10 °C below this temperature subtract value of 0,007 g/cm3 from the measured density; over 15 °C — add 0,007 g/cm3.
After determination of density of electrolyte in each can of the rechargeable battery establish degree of its razryazhennost according to
Measure density of electrolyte in each can. The difference in density of 0,04 g/cm3 or more between two any banks indicates loss of electrolyte or sulphation of plates.
If electrolyte density between two any banks differs more than on 0,04 g/cm3, the rechargeable battery should be replaced. If density of electrolyte is lower demanded, but identical in all banks, the battery needs to be charged.
Check operability of the unattended rechargeable battery only the voltmeter. Degree of state of charge of the battery with the built-in indicator is determined by color of the indicator. Green color of the indicator corresponds to a full charge, black — indicates the need of charging, blue — demonstrates to the low level of electrolyte in the battery.