Split charge battery start assist

An electrical system of a vehicle includes a first battery, a second battery, a first switch electrically connected in series between the first battery and the second battery, an external connection point, and a second switch electrically connected in series between the second battery and the external connection point. The system and a method of operating the system include determining that the first battery will need assistance to start an engine of the vehicle, opening the second switch in response to a state of charge of the second battery decreasing below a charge threshold, and closing the first switch for the second battery to assist the first battery to crank the engine for starting.

BACKGROUND

Motor vehicles typically include at least one primary battery. Types of batteries include lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries. The primary battery is used to start the motor of the vehicle. When the operator turns the ignition, current from the primary battery is provided to a solenoid switch causing the solenoid switch to close and electrically connect the primary battery to a starter. The starter converts the electrical energy from the primary battery into rotational kinetic energy to start the motor.

DETAILED DESCRIPTION

In addition to a primary battery, a vehicle may be equipped with one or more auxiliary batteries that may be used to provide power to non-vehicle loads, such as to charge or power electronic devices such as cell phones, tablets, laptops, speaker systems, lights, air compressors, power tools, etc. When the primary battery cannot start a vehicle on its own, one or more auxiliary batteries may be used to assist the primary battery to start the vehicle if the one or more auxiliary batteries have a sufficient state of charge.

In accordance with the present disclosure, a state of charge (SoC) of one or more auxiliary batteries (e.g., a “second battery”) can be maintained at a sufficient level to assist a primary battery (e.g., a “first battery”) when it is determined that the primary battery may be likely to need assistance, such as when the health of the primary battery is weak, when the primary battery is old, when the ambient temperature is low, when a SoC of the primary battery is low, or when the cranking speed produced by the primary battery is slowing over multiple consecutive starts. With a sufficient SoC, the one or more auxiliary batteries can be connected to the primary battery to assist in starting the vehicle when the primary battery needs assistance. Additionally, since the primary battery is typically best situated to start the vehicle, when a SoC of the primary battery is low, the one or more auxiliary batteries may be used to charge the primary battery during a key-off period.

In one or more implementations of the present disclosure, an electrical system of a vehicle includes a first battery, a second battery, a first switch electrically connected in series between the first battery and the second battery, an external connection point, a second switch electrically connected in series between the second battery and the external connection point, and a computer communicatively coupled to the first switch and the second switch. The computer may be programmed with computer executable instructions to determine that the first battery will need assistance to start an engine of the vehicle, instruct the second switch to open in response to a state of charge of the second battery decreasing below a charge threshold, and instruct the first switch to close for the second battery to assist the first battery crank the engine for starting.

In an example implementation, the instructions executable to determine that the first battery will need assistance may determine that a state of charge of the first battery is less than 50%, the instructions executable to instruct the second switch to open may be in response to the state of charge of the second battery decreasing below 60%, and the instructions executable to instruct the first switch to close may be performed before beginning to crank the engine.

In another example implementation, the instructions executable to determine that the first battery will need assistance may determine that a health of the first battery is weak, the instructions executable to instruct the second switch to open may be in response to the state of charge of the second battery decreasing below 70%, and the instructions executable to instruct the first switch to close may be performed before beginning to crank the engine.

In a further example implementation, the instructions executable to determine that the first battery will need assistance may determine that an age of the first battery has exceeded a threshold age, the instructions executable to instruct the second switch to open may be in response to the state of charge of the second battery decreasing below 70%, and the instructions executable to instruct the first switch to close may be performed before beginning to crank the engine.

In another example implementation, the instructions executable to determine that the first battery will need assistance may determine that an outside ambient temperature is or is predicted to be below 0° C. in a location of the vehicle within a next 24 hours, the instructions executable to instruct the second switch to open may be in response to the state of charge of the second battery decreasing below 70%, and the instructions executable to instruct the first switch to close may be performed before beginning to crank the engine.

In an example implementation, the instructions executable to determine that the first battery will need assistance may determine that a cranking speed during a first crank of a day is decreasing over a period of a last three starts, the instructions executable to instruct the second switch to open may be in response to the state of charge of the second battery decreasing below 70%, and the instructions executable to instruct the first switch to close may be performed before beginning to crank the engine.

In a further example implementation, the instructions executable to determine that the first battery will need assistance may determine that a state of charge of the first battery is below 40%, and the instructions executable to instruct the first switch to close may be performed during a key-off period and keep the first switch closed until the second battery has raised the state of charge of the first battery above 50%.

In yet another example implementation, the instructions executable to determine that the first battery will need assistance may further include instructions to determine that a voltage (V) of the first battery during cranking drops below 10 V, and the instructions executable to instruct the first switch to close may be performed during cranking.

In another example implementation, the instructions executable to determine that the first battery will need assistance may further include instructions to determine that a cranking speed in rotations per minute (RPM) during a cranking performed by the first battery is below 100 RPM, and the instructions executable to instruct the first switch to close may be performed during cranking. In this example, instructions may further send a notification that the first battery is performing poorly.

One or more implementations of the present disclosure may include a method of operating an electrical system of a vehicle having a first battery, a second battery, a first switch electrically connected in series between the first battery and the second battery, an external connection point, and a second switch electrically connected in series between the second battery and the external connection point. The method may include determining that the first battery will need assistance to start an engine of the vehicle, opening the second switch in response to a state of charge of the second battery decreasing below a charge threshold, and closing the first switch for the second battery to assist the first battery crank the engine for starting.

In an example method, determining that the first battery will need assistance may include determining that a state of charge of the first battery is less than 50%, opening of the second switch may be in response to the state of charge of the second battery decreasing below 60%, and closing of the first switch may be performed before beginning to crank the engine.

In another example of the method, determining that the first battery will need assistance may include determining that a health of the first battery is weak, opening of the second switch may be in response to the state of charge of the second battery decreasing below 70%, and closing of the first switch may be performed before beginning to crank the engine.

In a further example of the method, determining that the first battery will need assistance may include determining that an age of the first battery has exceeded a threshold age, opening of the second switch may be in response to the state of charge of the second battery decreasing below 70%, and closing of the first switch may be performed before beginning to crank the engine.

In yet another example of the method, determining that the first battery will need assistance may include determining that an outside ambient temperature is or is predicted to be below 0° C. in a location of the vehicle within a next 24 hours, opening of the second switch may be in response to the state of charge of the second battery decreasing below 70%, and closing of the first switch may be performed before beginning to crank the engine.

In a further example of the method, determining that the first battery will need assistance may include determining that a cranking speed during a first crank of a day is decreasing over a period of a last three starts, opening of the second switch may be in response to the state of charge of the second battery decreasing below 70%, and closing of the first switch may be performed before beginning to crank the engine.

In an example of the method, determining that the first battery will need assistance may include determining that a state of charge of the first battery is below 40%, and closing of the first switch may be performed during a key-off period and keep the first switch closed until the second battery has raised the state of charge of the first battery above 50%.

In another example of the method, determining that the first battery will need assistance may include determining that a voltage (V) of the first battery during cranking drops below 10 V, and closing of the first switch may be performed during cranking.

In a further example of the method, determining that the first battery will need assistance may include determining that a cranking speed in rotations per minute (RPM) during a cranking performed by the first battery is below 100 RPM, and closing of the first switch may be performed during cranking. This method may further include sending a notification that the first battery is performing poorly.

With reference to the Figures, wherein like numerals indicate like parts throughout the several views, a vehicle electrical system102for a vehicle100includes a first battery114, a first switch116, a second battery104, at least one external connection point106, a second switch108electrically connected in series between the second battery104and the at least one external connection point106, and a computer110communicatively coupled to the first switch116and second switch108. The computer110is programmed to instruct the second switch108to open in response to a state of charge of the second battery104decreasing below a charge threshold.

The external connection points106permit an operator to connect nonvehicle loads to the vehicle electrical system102. The second battery104provides power to the nonvehicle loads even when an ignition112of the vehicle100is off. (As described below, the vehicle100can include a first battery114separated from the second battery104by a first switch116, and the first battery114can be used to start the vehicle100.) Using the second switch108to disconnect the external connection point106from the second battery104at the charge threshold can maintain sufficient charge the second battery104to assist the first battery114when the first battery114may need assistance to start the vehicle100.

With reference toFIG.1, the vehicle100may be any suitable type of ground vehicle100, e.g., a passenger or commercial automobile such as a sedan, a coupe, a truck, a sport utility, a crossover, a van, a minivan, a taxi, a bus, etc.

With reference toFIG.2, the first battery114may be of any suitable type for vehicular electrification, for example, lithium-ion batteries, nickel-metal hydride batteries, lead-acid batteries, or ultracapacitors, as used in, for example, internal-combustion-engine (ICE) vehicles100, plug-in hybrid electric vehicles100(PHEVs), hybrid electric vehicles100(HEVs), or battery electric vehicles100(BEVs).

The vehicle100includes the ignition112. The ignition112can be movable by the operator between, e.g., an off state, an on state, an accessories state, and a starting state. For example, the ignition112can be a barrel rotatable between positions corresponding to the states, the ignition112can be a push button that is in the starting state when pressed. The ignition112can be biased to move out of the starting position, e.g., by having a spring that rotationally biases the barrel from the starting position to the on position or biases the button from the pressed position to the unpressed position. The ignition112is electrically connected to the first battery114. The first battery114is configured to supply power to a starter118in response to a signal from the ignition112. For example, when the ignition112is in the starting state, the ignition112supplies power from the first battery114to a solenoid, causing the solenoid to close and thereby complete a circuit for current to flow from the first battery114to the starter118.

The starter118can start an engine or motor (not shown) of the vehicle100. The starter118can be, e.g., an electric motor that rotates when a voltage is applied, e.g., by being electrically connected to the first battery114.

The first switch116is electrically connected in series between the first battery114and the second battery104. The first switch116is electrically connected in series between the first battery114and the second switch108. For example, the first switch116is electrically connected in series between the first battery114and a node120directly connected to the second battery104and the second switch108. When the first switch116is closed, current is permitted to flow between the first battery114and the second battery104and second switch108. When the first switch116is open, the first battery114is electrically isolated from the second battery104and second switch108.

The first switch116is switchable between closed and open. For example, the first switch116can be a relay, i.e., an electrically operated switch. The first switch116can switch from open to closed or vice versa in response to a signal, e.g., from the ignition112or the computer110.

The first switch116can be configured to be open in response to the ignition112being in the off state. For example, the ignition112can send a signal to the first switch116to open when turning off. The external connection points106thus do not draw down the first battery114when the vehicle100is not running. The first switch116can be configured to be closed in response to the ignition112being in the on state. For example, the ignition112can send a signal to the first switch116to close when the ignition112is released after starting the vehicle100. The motor can thus charge the second battery104along with the first battery114when the vehicle100is running.

The second battery104may be of any suitable type for vehicular electrification, for example, lithium-ion batteries, nickel-metal hydride batteries, lead-acid batteries, or ultracapacitors, as used in, for example, internal-combustion-engine (ICE) vehicles100, plug-in hybrid electric vehicles100(PHEVs), hybrid electric vehicles100(HEVs), or battery electric vehicles100(BEVs). The second battery104can have a lower capacity than the first battery114.

The vehicle100may include a third battery122. The third battery122may be of any suitable type for vehicular electrification, for example, lithium-ion batteries, nickel-metal hydride batteries, lead-acid batteries, or ultracapacitors, as used in, for example, internal-combustion-engine (ICE) vehicles100, plug-in hybrid electric vehicles100(PHEVs), hybrid electric vehicles100(HEVs), or battery electric vehicles100(BEVs). The third battery122can be connected in parallel to the second battery104. The third battery122can be connected to the node120that is directly connected to the second battery104, the second switch108, and the first switch116.

The second switch108is electrically connected in series between the second battery104and third battery122and the external connection points106. When the second switch108is closed, current is permitted to flow between the second battery104and third battery122and the external connection points106. When the first switch116is open, the external connection points106are electrically isolated from the second battery104and third battery122.

The second switch108is switchable between closed and open. For example, the second switch108can be a relay, i.e., an electrically operated switch. The second switch108can switch from open to closed or vice versa in response to a signal, e.g., from the ignition112or the computer110.

The vehicle electrical system102includes at least one external connection point106, e.g., a plurality of external connection points106. The external connection points106are features to which the operator can electrically connect nonvehicle loads, i.e., electrical loads that are not part of the vehicle100. When the second switch108is open, the second battery104and third battery122supply electricity to the nonvehicle loads via the external connection points106.

With reference toFIG.3, the external connection points106can be located in a position on the vehicle100in which the external connection points106are accessible to the operator and able to be covered when not in use. For example, the external connection points106can be located at a bottom of a driver seat124in a passenger cabin126of the vehicle100. Thus, a nonvehicle load located outside the vehicle100can be easily electrically connected to one of the external connection points106.

The external connection points106can be any type of feature to which a nonvehicle load can be securely and temporarily attached. For example, as shown inFIG.3, the external connection points106are studs, to which the nonvehicle loads can be electrically connected by clipping or screwing.

With reference toFIG.4, the computer110is a microprocessor-based computing device, e.g., a generic computing device including a processor and a memory, an electronic controller or the like, a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a combination of the foregoing, etc. Typically, a hardware description language such as VHDL (Very High-Speed Integrated Circuit Hardware Description Language) is used in electronic design automation to describe digital and mixed-signal systems such as FPGA and ASIC. For example, an ASIC is manufactured based on VHDL programming provided pre-manufacturing, whereas logical components inside an FPGA may be configured based on VHDL programming, e.g., stored in a memory electrically connected to the FPGA circuit. The computer110can thus include a processor, a memory, etc. The memory of the computer110can include media for storing instructions executable by the processor as well as for electronically storing data and/or databases, and/or the computer110can include structures such as the foregoing by which programming is provided. The computer110can be multiple computers110coupled together.

The computer110may transmit and receive data through a communications network128such as a controller area network (CAN) bus, Ethernet, Wi-Fi, Local Interconnect Network (LIN), onboard diagnostics connector (OBD-II), and/or by any other wired or wireless communications network128. The computer110may be communicatively coupled to the first switch116, the second switch108, a battery monitoring system130, a user interface132, a transceiver134, and other components via the communications network128.

The vehicle electrical system102can include the battery monitoring systems130for the first battery114, the second battery104, and the third battery122. As is known, the battery monitoring systems130can detect voltage, current, temperature, etc. The battery monitoring systems130can calculate state of charge, state of health, number of cycles, etc. The state of charge is the quantity of charge remaining in a battery. The state of health is an actual condition of a battery compared to its ideal condition, e.g., capacity, voltage, internal resistance, etc. The battery monitoring systems130may also store data relating to when a battery has been installed in order to calculate an age of the battery.

The user interface132presents information to and receives information from the operator of the vehicle100. The user interface132may be located, e.g., on an instrument panel in the passenger cabin126of the vehicle100, or wherever may be readily seen by the operator. The user interface132may include dials, digital readouts, screens, speakers, and so on for providing information to the operator, e.g., human-machine interface (HMI) elements such as are known. The user interface132may include buttons, knobs, keypads, microphone, and so on for receiving information from the operator.

The transceiver134may be adapted to transmit signals wirelessly through any suitable wireless communication protocol, such as cellular, Bluetooth®, Bluetooth® Low Energy (BLE), ultra-wideband (UWB), Wi-Fi, IEEE 802.11a/b/g/p, cellular-V2X (CV2X), Dedicated Short-Range Communications (DSRC), other RF (radio frequency) communications, etc. The transceiver134may be adapted to communicate with a remote server, that is, a server distinct and spaced from the vehicle100. The remote server may be located outside the vehicle100. For example, the remote server may be associated with another vehicle100(e.g., V2V communications), an infrastructure component (e.g., V2I communications), an emergency responder, a mobile device136associated with the operator of the vehicle100, etc. The transceiver134may be one device or may include a separate transmitter and receiver.

The mobile device136is a portable computing device such as a mobile phone, e.g., a smartphone, or a tablet. The mobile device136is a computing device including a processor and a memory. The mobile device136is associated with the vehicle100, e.g., is owned and carried by a person who may be the operator or owner of the vehicle100.

The computer110of the vehicle electrical system102can open the second switch108in response to a state of charge of the second battery104and/or third battery122decreasing below the charge threshold, thus isolating the external connection points106from the second battery104and third battery122. The charge threshold can be chosen to prevent the second battery104and/or third battery122from experiencing a deep discharge that may diminish a capacity of the second battery104and/or third battery122. In addition to opening the second switch108, the computer110of the vehicle electrical system102can also start the ignition112of the vehicle100in response to the state of charge of the second battery104and/or third battery122decreasing below the charge threshold, permitting the second battery104and third battery122to be recharged.

The charge threshold can vary based on the states of health of the first battery114, second battery104, and third battery122. The state of health is an actual condition of a battery compared to its ideal condition. For example, the state of health can be an actual charge capacity relative to an ideal or nominal charge capacity, e.g., of a newly manufactured battery, expressed as a percentage. For another example, the state of health can be a voltage of the battery, e.g., when fully charged, relative to an ideal or nominal voltage, e.g., of a newly manufactured battery that is fully charged, expressed as a percentage. For another example, the state of health can be a metric based on one or more measured values of the battery, e.g., internal resistance, capacity, voltage, self-discharge, ability to accept a charge, number of charge-discharge cycles, age of the battery, battery temperature, total energy charged and discharged, etc., as is known. The states of health of the batteries114,104, and122can be determined by the battery monitoring systems130and/or can be determined by the computer110based on data from the battery monitoring systems130.

The computer110can determine the charge threshold based on the state of health. The charge threshold can increase as the state of health of the second battery104and/or the third battery122decreases. For example, the computer110can determine the charge threshold to provide a buffer against a deep discharge, which may occur as the state of health decreases.

The computer110can also determine a state of charge (SoC) of the first battery114, the second battery104, and the third battery122. Thus, when an SoC of the first battery114is low (e.g., <50% or 40%), the second switch108may be opened by computer110to maintain the SoC of the second battery104and/or the third battery122at a higher level (e.g., 60% or 70%) so that the second battery104and/or the third battery122may be able to assist the first battery114in starting the vehicle100.

The computer110can provide a notification to the operator, as discussed below, when the first battery114is performing poorly.

The computer110can also provide a notification to the operator in response to the state of health of one of the batteries being below a health threshold. The operator can then replace the battery with the low state of health. The state of health is an actual condition of a battery compared to its ideal condition. For example, the state of health can be an actual charge capacity relative to an ideal or nominal charge capacity, e.g., of a newly manufactured battery, expressed as a percentage. For another example, the state of health can be a voltage of the battery, e.g., when fully charged, relative to an ideal or nominal voltage, e.g., of a newly manufactured battery that is fully charged, expressed as a percentage. For another example, the state of health can be a metric based on one or more measured values of the battery, e.g., internal resistance, capacity, voltage, self-discharge, ability to accept a charge, number of charge-discharge cycles, age of the battery, battery temperature, total energy charged and discharged, etc. The states of health of the batteries can be determined by the battery monitoring system130and/or can be determined by the computer110based on data from the battery monitoring system130.

The health threshold is a predetermined value stored in the memory of the computer110and expressed in the same units as the state of health. The health threshold can be different for the first battery114than for the second battery104and third battery122. The health threshold can be chosen to be above a point at which the battery is no longer suitable for its intended task, e.g., when the first battery114cannot reliably start the vehicle100or when the second battery104or third battery122cannot power a typical nonvehicle load for a period of time expected by a typical operator.

The vehicle electrical system102can also provide a notification to the operator in response to the rate of discharge of the second battery104and/or third battery122being above a rate threshold. The operator can then check the status of the nonvehicle loads drawing power from the second battery104and third battery122and, e.g., disconnect one or more of the nonvehicle loads or adjust one or more of the nonvehicle loads to draw less power. The rate of discharge can be determined as described above. The rate threshold is a predetermined value stored in the memory of the computer110and expressed in the same units as the rate of discharge. The rate threshold can be chosen to indicate that the rate of discharge is close to tripping a fuse, is generating high temperatures in the vehicle electrical system102, etc.

FIG.5is a process flow diagram illustrating an example process500for controlling the vehicle electrical system102. The memory of the computer110stores executable instructions for performing the steps of the process500and/or programming can be implemented in structures such as mentioned above. The computer110receives data from the battery monitoring system130and other sources (i.e., temperature data, cranking RPM's over time, etc.) and determines the state of health and state of charge for the first battery114, the second battery104, and/or the third battery122. In general, the determination steps of process500may be performed, at least partially, during a key-off period unless otherwise stated.

The process500begins in a block510, in which the computer110receives data (e.g., battery health, battery age, battery SoC, ambient temperature conditions, etc.) and determines if it is likely that the first battery114will need assistance to start the vehicle100. If it is determined that the first battery114will not need assistance at block510(“NO”), then the computer110can wait until additional data has been collected, and continue making determinations based on additional data. If it is determined at block510that the first battery114will need assistance (“YES”), the computer110receives the states of charge (SoC) of the second battery104and/or the third battery122from the battery monitoring system130. While the second battery104and/or the third battery122may be used to assist the first battery114, for brevity, only second battery104will be discussed relative toFIGS.5and6; it is to be understood that the third battery122could alternatively or additionally be employed if warranted.

In a block520, the computer110determines whether the SoC of second battery104has dropped below a minimum threshold. As discussed below with respect toFIG.6, the minimum threshold SoC for the second battery104may be set by computer110based upon the age/health/SoC of the first battery114or the current/expected ambient temperature conditions. If the SoC of the second battery104has not dropped below the threshold at block520(“NO”), the computer110can continue monitoring the SoC. If the SoC of the second battery104has dropped below the threshold at block520(“YES”), the method moves to block530.

In block530, the computer110sends a control signal to open the second switch108. This isolates the second battery104from loads at external connection points106to maintain an SoC in the second battery104sufficient to assist first battery114.

Next, in a block540, the computer110sends a control signal to close first switch116so that second battery104may assist first battery114start vehicle100. As discussed below with respect toFIG.6, this may occur during a key-off so that second battery104acts to charge first battery114, this may occur immediately before an ignition signal, or this may occur after an ignition signal and during cranking of the engine.

FIG.6is a more detailed process flow diagram illustrating an exemplary process600for controlling the vehicle electrical system102. While specific SoC percentages, voltage levels, cranking RPMs, and time periods are disclosed below, it is understand that variations in vehicle electrical systems and measurement precision may permit changes in these values without departing from the scope of the present disclosure, and the recited values may include variations of up to +/−5% or +/−10%.

In a first block605, computer110determines whether an SoC of the first battery114has dropped below 50%. If the SoC of the first battery114has dropped below 50% (“YES”), computer110sets the SoC threshold value for the second battery104at 60% in a block610so that sufficient charge is maintained in the second battery104to assist the first battery114. In a block620, computer110sends a control signal to close first switch116immediately prior to an ignition signal so that both the first battery114and the second battery104are used to crank the engine.

If the SoC of the first battery114has not dropped below 50% at block605(“NO”), computer110determines whether the health of the first battery114is weak based on the battery monitoring system130outputting, in a block615, data specifying that the battery114health is weak. If the health of the first battery114is weak (“YES”), computer110sets the SoC threshold value for the second battery104at 70% in a block640so that sufficient charge is maintained in the second battery104to assist the first battery114. Alternatively, computer110determines, in the block615, whether the RPMs measured during the last three initial starts of the day by the first battery114has been decreasing based on data from the battery monitoring system130in the block615. If the data indicates that the RPMs for the past three first starts of the day have been decreasing (“YES”), computer110sets the SoC threshold value for the second battery104at 70% in the block640so that sufficient charge is maintained in the second battery104to assist the first battery114.

Following the block640, in the block620, as discussed above, computer110sends a control signal to close first switch116immediately prior to an ignition signal so that both the first battery114and the second battery104are used to crank the engine.

If the health of the first battery114is not weak at block615(“NO”), computer110determines whether the age of the first battery114is over a set threshold (TH) in a block625. If the age of the first battery114is over the threshold TH (“YES”), computer110sets the SoC threshold value for the second battery104at 70% in a block640so that sufficient charge is maintained in the second battery104to assist the first battery114. Next, in block620, computer110sends a control signal to close first switch116immediately prior to an ignition signal so that both the first battery114and the second battery104are used to crank the engine.

If the age of the first battery114is not over the threshold at block625(“NO”), computer110determines whether the current and/or expected temperature for the next 24 hours is/will be below freezing (<0° C.) in a block635. If the 24-hour temperature will be below freezing (“YES”), computer110sets the SoC threshold value for the second battery104at 70% in the block640so that sufficient charge is maintained in the second battery104to assist the first battery114. The block620then follows the block640as explained above.

If the 24-hour temperature will not be below freezing at block635(“NO”), computer110determines whether an SoC of the first battery114has dropped below 40% in a block645. If the SoC of the first battery114has dropped below 40% (“YES”), computer110sends a control signal to close first switch116during a key-off period so that the first battery114may be charged by the second battery104(assuming it has a higher SoC) in a block650.

If the SoC of the first battery114is not below 40% at block645(“NO”), computer110and battery monitoring system130determine whether a voltage has dropped below 10 V during cranking of the engine in a block655. If the voltage has dropped below 10 V (“YES”), then, in a block660, computer110sends a control signal to close first switch116during cranking so that both the first battery114and the second battery104are used to crank the engine.

If the voltage from the first battery114has not dropped below 10 V during cranking at block655(“NO”), computer110determines whether a cranking speed has dropped below 100 RPM during cranking of the engine in a block665. If the RPM has dropped below 100 (“YES”), then, in the block660, computer110sends a control signal to close first switch116during cranking so that both the first battery114and the second battery104are used to crank the engine. As a cranking voltage below 10V or a cranking RPM below 100 indicate a poorly operating battery, computer110may send a notification, such as to the owner via user interface132or to a remote server, that the battery (i.e., the first battery114) is performing poorly and/or should be replaced.

A computer-readable medium (also referred to as a processor-readable medium) includes any non-transitory (e.g., tangible) medium that participates in providing data (e.g., instructions) that may be read by a computer (e.g., by a processor of a computer). Such a medium may take many forms, including, but not limited to, non-volatile media and volatile media. Instructions may be transmitted by one or more transmission media, including fiber optics, wires, wireless communication, including the internals that comprise a system bus coupled to a processor of a computer. Common forms of computer-readable media include, for example, RAM, a PROM, an EPROM, a FLASH-EEPROM, any other memory chip or cartridge, or any other medium from which a computer can read.

In the drawings, the same reference numbers indicate the same elements. Further, some or all of these elements could be changed. With regard to the media, processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted.

All terms used in the claims are intended to be given their plain and ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary. Use of “in response to” and “upon determining” indicates a causal relationship, not merely a temporal relationship. The adjectives “first,” “second,” and “third” are used throughout this document as identifiers and are not intended to signify importance, order, or quantity.