Abstract: A multiple voltage battery power supply system for operating a plurality of electrical vehicle loads at select voltage output levels is provided. The battery power supply system generally comprises at least two power blocks, each power block providing a voltage output for operating electrical vehicle loads. The at least two electrical power blocks are cascaded in series to provide a plurality of voltage output levels for powering vehicle loads at various rated voltages. Each power block independently maintains a substantially constant voltage, while the series combination of each power block also maintains a substantially constant voltage output across selected groups of blocks.