The Battery-Mate 100 is an industrial-rated charger designed for multi-shift operations along with efficient and problem-free charging. Sized and rated to charge 100% discharged batteries in 8 hours or less, the Battery-Mate 100 uses ferroresonant power conversion circuitry, which is virtually maintenance-free, to provide years of dependable service. The power conversion circuitry maximizes battery life by using a constantly tapering charge which is automatically regulated by the “On Charge” battery voltage. The output current of the charger is determined by the state of discharge of the battery. The battery is precisely charged, based on its depth of discharge.