A 200 V 2 kWh Li/LiV3O8 multicell system was constructed by seventy-seven 25 Wh single component cells in series connection and was operated under connection with a commercial power line, The discharge power of 1.94 kWh and the energy efficiency of over 93% were demonstrated almost as designed. The rate capability of this multicell system was poor compared with that of a single cell. The internal resistance of the system resulted in the iR loss, and the safely set operating voltage limits for the system reduced the output energy of individual cells. The non-uniformity of the operating voltage and of the state-of-charge for all component cells were also analyzed in addition to the local temperature rise in the stack.