During recharging, the battery is producing hydrogen gas.
Therefore, before recharging:
- Remove the vent plugs
- If recharging with the battery installed on the vehicle, be sure to disconnect the ground cable.
- Be sure the power switch on the recharger is off when connecting the charger cables to the battery and when disconnecting them.
Always charge the battery in an unconfined area. Do not charge the battery in a garage or closed room where there is not sufficient ventilation.
Never recharge the battery while the engine is running. Also be sure all accessories are turned off.