Three methods are proposed in this paper to reduce inrush current: by controlled three-phase switching; by resistor insertion and by changing the distribution of coil winding.

It is demonstrated that the battery performance can be predicted by monitoring the battery internal resistance,with its measuring method given.

The components of internal resistance of VRLA battery and its measurement principle and method were analyzed.

The relationship of operating performance of AA size Ni MH cell with its internal resistance during charge,over charge,and high rate discharge are studied using thermocouple method and several other internal resistance measuring methods.