Schumacher"s Automatic Charger with Engine Start is for use with 6 and 12 Volt batteries and includes 2 LED lights to signal full charge and check battery. Features 100 ampere engine start for emergency starting, 15 ampere fast charge for charging a battery in 2 to 4 hours, and 2 ampere trickle charge for charging a small 12 Volt battery in 2 to 12 hours. This charger is fully automatic and will not overcharge batteries.