precautions to be taken while charging of lead- acid battery: 1) Never keep the battery in the circuit and connect for external charging if it is not designed so. 2) While disconnecting / removing a battery first disconnect the negative terminal. 3) While connecting to charger, ensure that it is turned off. 4) Keep the charging voltage and current at levels specified by the maintenance manual. 5) The charge rate also depends on the external conditions such as temperature etc. so take care of the fact and set the rate. 6) Fast charging must be done with full supervision. 7) Inspect the electrolyte level and top up, if needed, else charging will not be of much use. 8) Never wear hanging jewellery while near a charging battery. 9) Do not keep tools etc on batteries. 10) Do not splash any liquids on the batteries, near the charger etc.