You don't have to worry about over-charging your batteries and possibly damaging them, as the Omni-Dok comes equipped with overcharge protection. The charger stops charging once the cells are fully charged. To guide you through the charging process, the Omni-Dok has built-in charging indicators on either side of the charger. Reverse polarity protection allows the charger to not charge if batteries are inserted improperly. Also, being that each bay is charged through independent channels, two different types of rechargeable batteries can be charged simultaneously. The Omni-Dok will automatically shut off after eight hours of non use to help conserve energy consumption.