Low maintenance or “sealed” lead acid batteries are widely used in cars and other vehicles like ATVs and golf carts. However, these batteries can be completely drained on occasion and must be recharged. The process is similar to that used for the older types of lead acid batteries (those that have removable caps on top for each battery cell). You do need to use a good charger and follow specific procedures to charge sealed lead acid battery, both for safety and to avoid damaging the battery.
Remove the battery from the vehicle to charge it. Charging a fully discharged lead acid battery off of a car alternator can result in an overcharge and may damage the battery. Use a crescent wrench to loosen the battery cables. Always wear safety goggles and protective gloves when working with lead acid batteries, even the sealed type. The sulfuric acid in the battery is extremely corrosive.