3. Charging

When a battery is to be recharged, proceed as follows:

3.1 Follow the battery charger manufacturer's instructions for using the charger. If the battery is to be charged while installed in the vehicle, disconnect the negative cable from the battery. NEVER CHARGE A FROZEN BATTERY. OVERCHARGING A BATTERY WILL DAMAGE IT. Refer to section "A" regarding explosive gases that are created during charging.

3.2 Determine the state of charge of the battery by measuring the electrolyte density. Top off the battery with distilled or tap water.





3.3 Determine the required charging time and current shown in the chart. The figures given are for a 100 % discharged battery. For a 1/4 discharged battery, charge at only 1/4 of the current (preferred) or for 1/4 of the time shown. For a 1/2 discharged battery, charge at only 1/2 of the current or time shown, etc. A slow charge is highly preferred over a fast charge, as the high temperature created by a fast charge can, if not carefully monitored, damage the battery permanently. Never allow the battery electrolyte temperature to exceed 125°F (51°C).

Note:
Do not exceed an initial charging voltage of 14.4 volts. The initial charging current may exceed that shown above, but should fall to the desired value within a few minutes.

3.4 Charge the battery. The battery is fully charged when the electrolyte density is between 1.26 and 1.28 or the cells are gassing freely at a law charging current rate.

3.5 The cell caps in Mercedes-Benz batteries are vented and provide a flame barrier. Do not remove, but loosen the vent caps for charging.

3.6 After charging, refill the battery with water to compensate for any water that may have been lost during charging.