Abstract: A battery discharge controller configured to control a hybrid system having first and second batteries includes a charged electric charge amount calculating section and a discharge controlling section. The discharge controlling section controls the DC/DC converter such that the first battery and the second battery are both discharged when a first reserve electric charge amount, which is a value obtained by subtracting a predetermined first lower limit electric charge amount from the charged electric charge amount of the first battery, has a positive value, a second reserve electric charge amount, which is a value obtained by subtracting a predetermined second lower limit electric charge amount from the charged electric charge amount of the second battery, has a positive value, and an absolute value of a difference between the first reserve electric charge amount and the second reserve electric charge amount is less than a predetermined threshold.

Abstract: A vehicle power supply device includes a relay controller. When a low voltage switching request is made to set a mode for supplying electric power from a switching module group to a low voltage power supply, the relay controller is configured to perform in sequence a first process of switching a first main relay and a second main relay to an open state, a second process of connecting a first switching relay to a second electrode terminal of the low voltage power supply and switching a second switching relay to a closed state, a third process of switching a precharge relay to a closed state and switching a third switching relay to a closed state, a fourth process of switching the second main relay to a closed state, and a fifth process of switching the precharge relay to an open state.

Abstract: A battery discharge controller configured to control a hybrid system having first and second batteries includes a charged electric charge amount calculating section and a discharge controlling section. The discharge controlling section controls the DC/DC converter such that the first battery and the second battery are both discharged when a first reserve electric charge amount, which is a value obtained by subtracting a predetermined first lower limit electric charge amount from the charged electric charge amount of the first battery, has a positive value, a second reserve electric charge amount, which is a value obtained by subtracting a predetermined second lower limit electric charge amount from the charged electric charge amount of the second battery, has a positive value, and an absolute value of a difference between the first reserve electric charge amount and the second reserve electric charge amount is less than a predetermined threshold.

Abstract: A vehicle power supply device includes a relay controller. When a low voltage switching request is made to set a mode for supplying electric power from a switching module group to a low voltage power supply, the relay controller is configured to perform in sequence a first process of switching a first main relay and a second main relay to an open state, a second process of connecting a first switching relay to a second electrode terminal of the low voltage power supply and switching a second switching relay to a closed state, a third process of switching a precharge relay to a closed state and switching a third switching relay to a closed state, a fourth process of switching the second main relay to a closed state, and a fifth process of switching the precharge relay to an open state.