The Auto Charge 12 HO, Model 091-170, is a high output fully automatic battery charger for vehicles with a single battery system. A patented "Sample & Hold" circuit is utilized to detect the actual battery voltage. This eliminates the error due to the current flowing in the charging wires and assures that the battery is charged to the precise float voltage. A current limiter prevents overloading the charger when charging a deeply discharged battery or driving large parasitic loads. The charger is ruggedly constructed to assure reliable operation when mounted in a vehicle.