Set the battery charger to 12 V/ 2 amps and allow the battery charge for 36 hours. After, use your voltmeter and ensure it checks out between 12.43 V and 12.6 V before you check it. You'll start by heating four cups of distilled water, then pour it into a clean bucket. Next off, put around 4 ounces of Epsom salts right into the water and stir up un