3. Charging

3.1. Whenever a battery reaches a charge level of 75% or less it must be recharged. Only charge the battery as much as it needs. Overcharging will damage the battery.

3.2. Before charging a battery, three steps must be performed:

one; determine the amount of charge the battery needs by performing a No-load Test (section 2),

two; top off the battery with distilled (or tap) water, and

three; determine charging time and current according to the table below.





3.3. The preceding figures are for a 100% fully discharged battery. For a 25% discharged (75% charged) battery, charge at only 1/4 the current (preferred) or 1/4 the time. For a 50% discharged/charged battery, charge at only 1/2 the current or time shown (etc.). A slow charge is preferred over a fast charge as the high temperatures created by a fast charge, if not carefully monitored and controlled, can damage the battery permanently. The battery electrolyte temperature must be maintained between 60° and 125° F (16° and 51° C) during charging.

3.4. Do not exceed initial charging voltage of 14.4 volts. The initial charging current must not exceed that shown in table above. Higher charging currents can cause permanent battery damage.

3.5. The battery is fully charged when the electrolyte specific gravity is between 1.26 and 1.28, or the cells are gassing freely at a low charging current.

3.6. The cell caps on all Mercedes-Benz batteries are vented and provide a flame barrier Therefore, do not remove the vent caps when charging a Mercedes-Benz battery.

3.7. After charging, top-off battery cells with distilled (or tap) water to replace any that may have been lost during charging.