Battery chargers, electrical systems, and rechargeable battery charging methods are described. According to one aspect, a battery charger includes charge circuitry configured to apply a plurality of main charging pulses of electrical energy to a plurality of rechargeable cells of a battery to charge the rechargeable cells during a common charge cycle of the battery and to apply a plurality of secondary charging pulses of electrical energy to less than all of the rechargeable cells of the battery during the common charge cycle of the battery to charge the less than all of the rechargeable cells.