In a system that shares a battery with an external device, the system includes a power storage device connected to the battery via a power supply line. The system includes a switch provided on the power supply line, and a control unit. The control unit controls on-off switching operations of the switch to selectively establish an electrical conduction between the battery and the power storage device or interrupt the electrical conduction therebetween. The battery has a battery voltage thereacross, and the power storage device has a power-storage voltage thereacross. The battery charges the power storage device while the electrical conduction is established so that the power-storage voltage follows the battery voltage. The control unit turns off the switch when the battery voltage is in a predetermined insufficient voltage state to prevent electrical power charged in the power storage device from being discharged to the battery.

A vehicle power supply system, mounted on a vehicle including an internal combustion engine, includes: a main power supply system including a main low-voltage power supply; and a backup power supply system including a backup low-voltage power supply. A starter motor that starts the internal combustion engine is connected to the main power supply system. At least one of a vehicle control device, configured to control the main power supply system, the backup power supply system, the internal combustion engine and the starter motor, and a backup power supply control device of the backup power supply system is configured to execute an abnormality determination processing of determining whether an abnormality occurs in the main power supply system, and does not execute the abnormality determination processing when the starter motor is in operation, or determines that no abnormality occurs in the main power supply system in the abnormality determination processing.

The invention relates to a method for predicting an engine-start performance of an electrical energy storage system, in particular a motor vehicle starter battery. The method comprises the following method steps: generating engine-start data which are characteristic of the electrical energy storage system; evaluating the generated engine-start data; and outputting a result of the evaluation, which result relates to a prediction with respect to the engine-start performance of the electrical energy storage system. According to the invention, provision is made in particular for a vehicle make, a vehicle model and/or a vehicle variant of a vehicle to be started by the electrical energy storage system to be taken into account in order to evaluate the generated engine-start data.

A vehicle determines a first resistance of a starter motor and a starter cable connected thereto based at least in part on the first voltage of a power source. The vehicle determines a predicted minimum battery voltage based at least in part on the first resistance of the starter motor and the starter cable. The vehicle, in response to the predicted minimum battery voltage satisfying a threshold, enables a vehicle stop-start function, and, in response to the predicted minimum battery voltage failing to satisfy the threshold, disables the vehicle stop-start function.

A booster is mounted on a vehicle having an idle stop function. The booster boosts an input voltage supplied from a battery, and outputs the boosted input voltage to an in-vehicle device. The booster includes a booster circuit and an output voltage sensor. The booster circuit is a chopper-type, and includes a reactor having one end connected to the battery and a switching element connected between an other end of the reactor and a ground. The output voltage sensor detects an output voltage of the booster circuit.

It is possible to accurately estimate a starting current and calculate a precise starting minimum voltage without being influenced by a change in a storage battery state or a starting state by updating a current/voltage correlation characteristic corresponding to a deterioration state of a storage battery each time a current/voltage data set obtained when a starter is driven is newly stored in association with the deterioration state of the storage battery and by calculating the starting current corresponding to a present voltage immediately before start in accordance with the current/voltage correlation characteristic corresponding to the present deterioration state of the storage battery when determination is made as to whether or not to drive the starter.

A vehicle power source includes a generator motor coupled to an engine, a first power storage, a second power storage, a conduction switch, and a switch controller. The first and the second power storages are coupled, in parallel, to the generator motor. The conduction switch is subject to change between a conductive state and a cut-off state of the generator motor and the second power storage. The switch controller changes the conduction switch from the conductive state to the cut-off state, on a condition that the generator motor is controlled in a powered state. The switch controller changes the conduction switch from the cut-off state to the conductive state, on a condition that the second power storage discharges in excess of a threshold, with the conductive switch changed to the cut-off state.

The vehicle power supply system includes the DC/DC converter that is disposed on an electric path between the first load related to vehicle control and the battery and converts a voltage of direct current power supplied from the battery to the first load, and the detection device that detects the voltage of the battery. In a case where the engine is restarted by using the starter from the automatically stopped state of the engine, the detection device controls the DC/DC converter to start in a case where the voltage of the battery becomes equal to or less than a threshold value during a period from stoppage of the alternator to start of the starter.

A control apparatus includes a first determination section determining whether a power-supply voltage has decreased below a first threshold value, an interruption section interrupting a current flow to an inverter if the voltage has decreased below the first threshold value, a second determination section that determining whether the power-supply voltage has increased above a second threshold value, an interruption releasing section releasing the interruption based on the fact that the voltage has increased above the second threshold value, a count section counting the number of interruptions, a limiting section determining whether the decrease in the power-supply voltage is caused by a first factor of an electric rotating machine or a second factor, and limits the counting if the decrease in the power-supply voltage is caused by the second factor, and a third determination section determining whether the interruption is allowed to be released based on the number of interruptions.

A battery combiner may be used to electrically isolate first and second batteries during conditions in which a first battery required for a mechanical drive system may experience excessive power draw. The second battery may be used to provide a switched and/or continuous power source to a control system and/or other electrical devices for reliable operation, and the combiner may join the first and second batteries together such that both are electrically charged by a single alternator during conditions when it is safe.