Abstract: A rechargeable battery is provided with an overcharge protection circuit which is particularly adapted for nickel metal hydride battery packs to be used in conventional charging adapters suitable for NI-CAD battery packs. The battery pack includes a microprocessor which measures the voltage across the electrical contacts of the battery pack. Upon reaching peak charge, the microprocessor increases the voltage appearing across the battery pack contacts. After a predetermined time period as measured by the microprocessor, the microprocessor decreases the voltage appearing across the battery pack terminals to exceed the change in voltage to which the charging adapter responds to terminate a high rate of charging.