Designed for totally automatic, unattended operation. All you have to do is set the front-panel switch to "automatic", and the Sentry charger takes over. As the battery approaches full charge, the Sentry's ferro-resonant transformer gradually tapers back the charging current. Then the charger turns itself completely off until it's needed again. When it's off, it's completely off.
Sentry FR-series chargers are available in a wide range of 12V, 24V and 32V models, with output current ranging from 20 to 60 amps. Standard input power is 115 or 230 VAC power. Models are available for 50/60 Hz operation. A manual/automatic selector switch, ammeter, full charge and power indicator are conveniently located on the front panel.