Mercedes-Benz S-class W140 - Repair manual and operation

7.2.3. Storage of the rechargeable battery

If the car was not used more than two months, the rechargeable battery needs to be removed and charged. Optimum temperature of storage of the battery makes from 0 to +27 °C. At these temperatures a battery self-discharge minimum. It is necessary to charge the battery at least once in two months, otherwise it becomes useless.

The battery which was not used a long time (for example, the car was not operated), is discharged and, besides, can sulfatirovatsya. If such battery is charged with the device for a bystry charge, it does not perceive charging current or owing to sulphation becomes too quickly "completely" loaded. Actually the battery is damaged.

Before defining the battery as damaged it is necessary to check the following:

Electrolyte density. If the difference between density in separate sections does not exceed 0.04 g/ml, then it is necessary to charge the battery with the normal charger;

After a charge check the battery under loading. If characteristics of the battery below given in Specifications the battery it is damaged;

If electrolyte density in one or in two next sections considerably differs (for example, in five sections of 1.16 g/ml, and in the sixth 1.08 g/ml) the battery has short circuit and it needs to be replaced.