Electric vehicle battery system and method

An electric vehicle has an electric power source 10 and an electric motor 12 that also turns a motive battery top-up alternator 18 that in part recharges the motive battery. The power source 10 may be a motive battery, in part charged by the alternator 18, in which case switches 40 may ensure that the alternator 18 only charges the battery 10 when the vehicle is slowing or braking (regenerative braking). The alternator 18 may also charge an ancillary battery. The electric power source 10 may be a fuel cell. The ancillary battery can provide power to the motor 12 either together with or independently from power from the battery or fuel cell. One or more ancillary service alternators 30 42 may charge one or more ancillary service batteries 32 44 that each drive one or more ancillary vehicle services or systems.