1998 Honda Civic Owner's Manual - Page 175
1998 Honda Civic Manual
Page 175 highlights
Battery If you need to connect the battery to a charger, disconnect both cables to prevent damage to the vehicle's electrical system. NOTICE Charging the battery with the cables connected can seriously damage your vehicle's electronic controls. Detach the battery cables before connecting the battery to a charger. The battery gives off explosive hydrogen gas during normal operation. A spark or flame can cause the battery to explode with enough force to kill or seriously hurt you. Wear protective clothing and a face shield, or have a skilled mechanic do the battery maintenance. If the terminals are severely corroded, clean them with baking soda and water. Then use a wrench to loosen and remove the cables from the terminals. Always disconnect the negative (-) cable first and reconnect it last. Clean the battery terminals with a terminal cleaning tool or wire brush. Reconnect and tighten the cables, then coat the terminals with grease. Maintenance