Patent ID: 7508091

Claim:
A vehicle battery protection device for preventing a vehicle battery from being drained to the point that it cannot restart a motor vehicle, the device being wired in series between the vehicle battery and the vehicle starter motor, comprising: at least one electrical property measuring device for measuring at least one electrical property of the electricity flowing from the battery; a microprocessor that compares the at least one measured electrical property with a minimum battery value, and if the comparison indicates that the electrical property measured corresponds to a situation where the vehicle engine has been left off and that the charge in the vehicle battery is less than a preset minimum starter value, the microprocessor operates a switch that opens the circuit between the starter motor and the battery and actuates an indicator notifying the vehicle operator that the device has been activated to protect the vehicle battery, said switch having a reset means to enable the circuit to be reconnected, wherein the minimum battery value is determined by using the electrical property measuring device to measure an average load drawn when starting the vehicle, and adding a safety margin to the measured average value.