A battery charging apparatus and method is disclosed. The battery charger includes a programmable two level constant current source having an inhibit input. A clock signal is fed to counting stages which time out after a specified time, during which time the battery is charged with constant current. A temperature sensing circuit detects the temperature of the charging battery and will allow the battery to charge at a reduced rate for a longer time period if the temperature increases above a threshold level. Once the counting stages time out, the battery charger pulse charges the battery at the reduced current level, preferably at a 20% duty cycle, at relatively long intervals to keep the battery from self discharging.