HV Batteries are made of single batteries connected in series, to obtain the high voltage. If one of the 7.2 volt batteries go bad, the whole HV Battery does not work. If the only problem is with one battery, do not replace the whole thing. Replace only the bad cell. A lot of people including automotive professionals are afraid of high voltages, this vehicles are very safe to work on. Refurbishing the HV batteries is always possible and at a fraction of what the Toyota dealer wants. For more information on do it yourself or get it done, contact barsomtire@aol.com and ask about it.