The battery should be inspected to ensure it is in perfect physical condition. The charger cables must be connected to ensure a good contact, taking care that the polarity is correct, otherwise battery, vehicle or charger could be damaged. The specified torque loading for the polscrews of the charger cables and connectors is: 20–25 Nm. The level of the electrolyte must be checked. If it is below the pole bridge, it must first be topped up to this height with purified water (DIN 43530 part 4). The battery is then charged as in item 2.2. After charging, the electrolyte should be topped up to the specified level with purified water.
Be sure that all breather holes are not sealed or covered. Electrical connections must only be made or broken in the open circuit condition to avoid sparks and explosion risks. To achieve the optimum life for the battery, operating discharges of more than 80 % of the rated capacity should be avoided (deep discharge). Discharged batteries must be recharged immediately and must not be left discharged. This also applies to partially discharged batteries.