Possible faults of the battery (VAZ-21011)

Cause	Method of elimination
Battery discharge during vehicle operation
Alternator drive belt slippage	Adjust the belt tension
Excessive contamination of the battery surface	Clean the surface of the battery
Damage to insulation in electrical equipment system (discharge current more than 1 mA with consumers disconnected)	Find the location of the current leak and repair the damage
Connection of new consumers by the car owner in excess of permissible limits	Turn off new electricity consumers
Generator faulty	Check the generator
Electrolyte contamination with foreign impurities	Charge the battery, drain the electrolyte, rinse, fill with fresh electrolyte and charge the battery again
Short circuit between plates	Replace the battery
The electrolyte level is below the upper edge of the plates	Restore normal electrolyte levels
Electrolyte on the surface of the battery
Elevated electrolyte level causing splashing	Set the electrolyte level to normal
Electrolyte leaking through cracks in the housing	Replace the battery
Electrolyte boiling due to very high generator voltage	Check the reliability of the connection to the ground of the voltage regulator housing and the correct connection of the wires to it; adjust or replace the voltage regulator
Boiling of electrolyte and overheating of the battery due to sulfation of the plates	Replace the battery