Patent ID: 9682673
Date: 2017-06-20
CPC Classifications: B60R,H01M,H02J,Y02E

Claim:
1. A vehicle power supply device comprising: a first battery being connectable to a starter motor, a vehicle load, and a generator; a second battery being different from the first battery in electric characteristics; a connecting switch being connected between the first battery and the second battery, and connecting the second battery to the first battery in parallel in an ON state of the connecting switch; and a control circuit controlling the connecting switch, wherein in the ON state of the connecting switch, the generator charges the first battery and the second battery, wherein the control circuit controls to change to an OFF state of the connecting switch in a state of providing electric power to the starter motor, or in a state of detecting an open condition including an abnormal state of the first battery and/or the second battery, and to hold the connecting switch in the ON state in a normal state in which the open condition is not detected, wherein the control circuit comprises a remaining capacity detecting portion detecting a remaining capacity of the second battery, and a power generation determining portion determining a generating state or a non-generating state in a vehicle side, and wherein when the remaining capacity detected in the remaining capacity detecting portion is more than a maximum remaining capacity and the power generation determining portion determines that the vehicle side is in the generating state, or when the remaining capacity detected in the remaining capacity detecting portion is less than a minimum remaining capacity and the power generation determining portion determines that the vehicle side is in the non-generating state, the control circuit holds the connecting switch in the OFF state, regarded as the open condition.