Abstract: The present invention is directed to a method for automatically maintaining rechargeable batteries at maximum capacity and includes the steps of detecting the presence of a battery, deep discharging the battery to a predetermined level above cell reversal, recharging the battery to its rated capacity, discharging the battery at a controlled rate while measuring battery output voltage and determining whether its capacity is above or below a selected minimum, deep discharging and recharging if the battery is below the selected minimum until reversible memory effects are removed, providing a positive indication of battery failure, maintaining the full battery capacity by trickle charging, and periodically repeating the above steps to avoid onset of battery memory.