System and method for monitoring battery equalization

A system and method for protecting against battery overcharging is used with an automotive electrical system having an alternator that supplies an output voltage VOUT to a string of at least first and second series-connected rechargeable batteries, an equalizer coupled to at least the first and second batteries, and at least a higher voltage load or a lower voltage load connected across respective sets of batteries of the string. The voltage VOUT is regulated to a target value VTARGET, and this target value VTARGET is reduced when either the voltage V1 across the first battery exceeds a first threshold value T1 or when a voltage V2 across the second battery exceeds a second threshold value T2. In this way, both of the batteries are protected against over-voltage conditions. A warning signal is illuminated to indicate to a user when either of the batteries is outside of its normal operating range.