NOVELTY - A power pack (10) comprises a series group connecting in series multiple electrical power sources (16); a series balancing circuit (54) configured to balance the voltage of power sources in the series group; and electronics (32) configured to electrically disconnect one or more of power sources in the balanced series group such that when series balancing circuit is balancing the voltages the disconnected power sources is disabled from recharging the other power sources in balanced series group.    USE - Power pack for high power applications such as powering the movement of vehicles, particularly trucks, cars and carts.    ADVANTAGE - The power pack can balance the voltage of the power sources in both the parallel groups and in the series groups. The ability to balance these power sources can permit the power pack to overcome issues associated with variance in the performance of different power sources. The electronics can continually operate or periodically operate the power management circuits so as to provide series balancing of the series groups.    DETAILED DESCRIPTION - A power pack (10) comprises:    (A) a series group connecting in series multiple electrical power sources (16);    (B) a series balancing circuit (54) configured to balance the voltage of power sources in the series group such that one or more power sources in the series group recharges one or more other power sources in the same series group; and    (C) electronics (32) configured to electrically disconnect one or more of the power sources in the balanced series group such that when the series balancing circuit is balancing the voltages the one or more disconnected power sources is disabled from recharging the other power sources in the balanced series group and the other power sources in the balanced series group are disabled from recharging the one or more disconnected power sources.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram of a power pack.    Power pack (10)    Electrical power source (16)    Primary series line (18)    Electronics (32)    Shunt circuit (44)    Resistor (48)    Series balancing circuit (54)