If possible, from the vehicle to prevent potential damage to the alternator or vehicle bodywork from acid spills.

If the needle does not move when connected to a battery that is known to be flat, check the terminal connections for a firm, clean contact. If the battery is already fully charged, the needle may not move at all.

Charging lead-acid batteries releases flammable gases. Always operate in a well-ventilated area away from sparks or naked flames.

As the battery reaches full charge, the needle will gradually drop toward zero.