A hand held, portable jump starter device includes a multi-cell rechargeable battery with at least three battery cells connected in series, and a battery cell equalization circuit connected to the multi-cell rechargeable battery in parallel with the battery charge controller, wherein the battery cell equalization circuit includes an individual battery cell equalization circuit for each of the at least three battery cells, and wherein each of the individual battery cell equalization circuits is configured to discharge a particular battery cell upon the particular battery cell reaching a cell voltage exceeding a pre-determined upper voltage threshold until the particular battery cell reaches a pre-determined lower voltage level below the upper voltage threshold, and wherein the individual battery cell equalization circuits are configured to charge lower voltage individual battery cells at a higher rate allowing lower voltage individual battery cells to catch up in voltage to an individual battery cell having a highest voltage.