Charge/float motor vehicle electrical system

摘要

A motor vehicle electrical system having a charge mode of operation wherein the motor vehicle battery receives charging current at a temperature compensated voltage from an engine-driven generator, and a float mode operation wherein the battery charging current is reduced to a low value, sufficient only to prevent self-discharge of the battery. The charge and float modes of operation are alternately engaged as a function of the battery state of charge. During the charge mode of operation, a sufficiently high state of charge is detected as a function of the magnitude of the charging current, and during the float mode of operation, a depleted state of charge is detected as a function of the battery voltage. A timer provides a periodic return to the charge mode of operation to sample the battery state of charge.