Abstract: A battery charger (10) and associated method for maintaining the charge of a battery (12). The battery charger (10) has a processor (16), power supply (14) and power regulator (15). The battery charger (10) first applies a high current charge to the battery (12), which is terminated when the battery voltage or temperature reaches a defined limit. Then the battery charger (10) applies a low current charge (102) for a set period of time. Next, no charge is applied until the battery (12) cools to an ambient temperature. The ambient temperature is then measured using a thermistor (18) in the battery (12). If the ambient temperature is above a certain threshold no charge is applied for a wait period. If the ambient temperature is below the threshold the low current charge is applied for a the set period of time.