(JP9009402-A)      The overdischarge prevention circuit uses low voltage power from a DC-DC convertor (6) to supply an exciting winding (8a) of a relay and to also supply a low voltage secondary battery (7) through a diode (14). The low voltage power is supplied to low voltage loads (5) through a contact (8b) of the relay. The DC-DC converter is constructed so that low voltage power output is stopped when the output voltage is reduced to a value less than a specified range due to a reduction in battery capacity. If the main switch is left in the closed position the converter output is stopped and the contact (8b) of the relay is opened thus preventing discharge of the low voltage secondary battery.    ADVANTAGE -   Uses simple circuit configuration and low voltage switching    (US5793189-A)      The overdischarge prevention circuit uses low voltage power from a DC-DC convertor (6) to supply an exciting winding (8a) of a relay and to also supply a low voltage secondary battery (7) through a diode (14). The low voltage power is supplied to low voltage loads (5) through a contact (8b) of the relay. The DC-DC converter is constructed so that low voltage power output is stopped when the output voltage is reduced to a value less than a specified range due to a reduction in battery capacity. If the main switch is left in the closed position the converter output is stopped and the contact (8b) of the relay is opened thus preventing discharge of the low voltage secondary battery.    ADVANTAGE -   Uses simple circuit configuration and low voltage switching    (EP750384-B1)      The overdischarge prevention circuit uses low voltage power from a DC-DC convertor (6) to supply an exciting winding (8a) of a relay and to also supply a low voltage secondary battery (7) through a diode (14). The low voltage power is supplied to low voltage loads (5) through a contact (8b) of the relay. The DC-DC converter is constructed so that low voltage power output is stopped when the output voltage is reduced to a value less than a specified range due to a reduction in battery capacity. If the main switch is left in the closed position the converter output is stopped and the contact (8b) of the relay is opened thus preventing discharge of the low voltage secondary battery.    ADVANTAGE -   Uses simple circuit configuration and low voltage switching