Clean any corrosion off of the battery using a mix of warm water and baking soda. Mix 1 lb. of soda with each gallon of water you use. Clean the battery terminals and the inside of the clamps with a post and clamp cleaner.
Recharge the battery immediately after using it, charging it someplace well-ventilated with no flames or sparks present. Use a charger with a charge rate that's within 10 to 13 percent of the battery's 20-hour AH capacity. A three-stage charger that performs a bulk charge, absorption charge and float charge works best.
Test the battery's voltage with a digital DC voltmeter to check its state of charge. Recharge the battery if the voltage is below 70 percent, which is 12.37 on a 12-volt battery and 6.19 on a 6-volt. The battery is fully charged at 12.73 (12-volt) or 6.37 (6-volt).
Refill the electrolyte level by removing the vent caps and using mineral-free water (distilled works best). Fill it to just above the plates if the level is below that. Then don't add any more water until the battery is charged. Fill a charged battery up to 1/8 inch below the fill well.
