Power system for a vehicle

A power system for a vehicle, comprising:

• a high voltage battery;
• a low voltage DC-DC converter configured to step down a voltage of the high voltage battery and to output the stepped-down voltage, the low voltage DC-DC converter including a first low voltage DC-DC converter and a second low voltage DC-DC converter;
• a low voltage battery charged by an output current of the low voltage DC-DC converter, wherein the low voltage battery includes:
• a first cell group including a plurality of battery cells,
• a second cell group connected in parallel with the first cell group and including a plurality of battery cells, and
• a plurality of switches configured to electrically connect or disconnect the first cell group or the second cell group with the low voltage DC-DC converter,
• wherein the plurality of switches includes:
• a first switch connected between an output terminal of the first low voltage DC-DC converter and the first cell group;
• a second switch connected between an output terminal of the second low voltage converter and the second cell group;
• and
• a third switch comprising a first end connected between the first switch and the output terminal of the first low voltage DC-DC converter and a second end connected between the second switch and the output terminal of the second low voltage DC-DC converter;
• electrical loads configured to receive power from at least one of the low voltage DC-DC converter or the low voltage battery;
• and
• a controller configured to control opening or closing of the plurality of switches,
• wherein the third switch is connected to the first cell group and the second cell group such that the electrical loads receive power from at least one of the first cell group or the second cell group even when the third switch is opened.