Protection of battery cells from overcharge and from over-discharge is an important criteria for the successful operation of battery cells over long lifetimes. Battery level charge control based on cell level parameters also improves battery operation. Circuitry to perform both of these functions has been developed by TRW Systems under contract with the Wright-Patterson Air Force Base Aero Propulsion Laboratory on the 2 KW Long Life Battery Program, Air Force Contract No. F33615-70-C-1627 and on several earlier programs.