If the battery becomes hot to the touch at any time during the charging process, disconnect the battery charger and let the battery cool before reconnecting it. Hot batteries can explode! As shown in the following illustration, the open-circuit voltage of an MF battery sta- bilizes about 30 minutes after charging has been completed. Therefore, wait 30 minutes after charging is completed before measuring the open-circuit volt- age. 3 - 76 CHECKING AND CHARGING THE BATTERY CHK ADJ