Abstract: A charging device includes: a holder detachably connected to a connector of a camera head to which an endoscope is detachably connected; and a power supplier configured to supply power to a battery of the camera head held by the holder.

Abstract: A selectable USB charging cable which may have a switch configured to permissively control the transmission of an electrical current between two internet connected, or electronically powered, devices. By use of the reversibly selectable switch, a user of the charging cable may select an on configuration or an off configuration of the switch. The switch may reversibly stop the transmission of the electrical current between two electronically powered devices by use of a permissible selection between the on configuration and off configuration of the switch. The electrical current stopped by the switch may correspond to data transmission or power transmission to or from an electronically powered device.

Abstract: A charging system includes a plurality of power charging cabinets, each power charging cabinet being configured with a plurality of electrical power outputs. The charging system also includes at least one power dispenser chain coupled to at least one of the plurality of electrical power outputs, each of the power dispenser chains having more than one addressable power dispenser electrically coupled thereto and each of the power dispensers being configured to be addressed based on a vehicle identifier of a vehicle coupled to an addressed power dispenser, each of the power dispensers also having a controller configured to control electrical power delivery to a destination chosen from a charging power output of the power dispenser and to another power dispenser in the power dispenser chain. The charging system further includes a central control system configured to communicate with controllers of the power dispensers of the at least one power dispenser chain.

Abstract: Devices, systems, and methods are provided for mitigating vehicle power loss. A vehicle charging system may include a power supply, and a voltage control device associated with receiving first voltage from the power supply, providing the first voltage to a hybrid vehicle or a battery electric vehicle, and blocking a second voltage from the hybrid vehicle or the battery electric vehicle, wherein the vehicle charging system is external to the hybrid vehicle or the battery electric vehicle.

Abstract: A method provides a mobile device positioned in a case. The mobile device has a wireless power transmitter. The case has a magnetically attractive portion. A mobile accessory having a magnetic coupling portion and a wireless power receiver is provided. The mobile accessory includes a functional component. The accessory is coupled with the case such that the wireless power transmitter of the mobile device is positioned to transfer wireless power to the wireless power receiver of the accessory. Power is wirelessly transmitted from the mobile device to the accessory. The functional component of the accessory is activated while power is transferred wirelessly.

Abstract: The present invention provides an electronic device and an accessory with quick charging and audio transmission functions. The electronic device can be respectively connected to a charger and an audio connector through the accessory. The electronic device includes a quick charging controller and a device Type-C female socket. The quick charging controller is used for performing quick charging protocol communication by utilizing the SBU pins of the device Type-C female socket and the D+ pin and the D? pin of a charger connected to the accessory when the accessory is connected to the device Type-C female socket and the charger is connected to the accessory. The present invention breaks through the usual thought of using the CC pin to perform quick charging protocol communication in the existing quick charging mode. Further, when the accessory with the audio transmission function is used, the quick charging can also be performed.

Abstract: An all-solid-state secondary battery including: a cathode including a cathode active material layer; an anode including an anode current collector, and an anode active material layer on the anode current collector, wherein the anode active material layer includes an anode active material which is alloyable with lithium or forms a compound with lithium; and a solid electrolyte layer between the cathode and the anode, wherein a ratio of an initial charge capacity (b) of the anode active material layer to an initial charge capacity (a) of the cathode active material layer satisfies a condition of Equation 1: 0.01<(b/a)<0.5, wherein a is the initial charge capacity of the cathode active material layer determined from a first open circuit voltage to a maximum charging voltage, and b is the initial charge capacity of the anode active material layer determined from a second open circuit voltage to 0.01 volts vs. Li/Li+.

Abstract: Inductive charging techniques utilize a plurality of transmitter coils arranged in a predetermined configuration and each being configured to, when active, inductively transfer power to a receiver coil of a wireless device and a controller configured to control a charging session during which power is inductively transferred from at least one of the plurality of transmitter coils to the receiver coil of the wireless device, including monitoring electrical parameters of at least two transmitter coils of the plurality of transmitter coils, wherein the at least two monitored transmitter coils comprise at least one active transmitter coil, based on the monitoring, determining a position of the receiver coil relative to the plurality of transmitter coils, and selectively activating and/or deactivating at least one of the plurality of transmitter coils based on the monitoring when the position of the receiver coil changes to provide uninterrupted inductive power transfer.

Abstract: Certain aspects of the present disclosure generally relate to an adaptive combination power supply circuit. The adaptive combination power supply circuit may be capable of switching between performing as a three-level buck converter and as a divide-by-two charge pump. One example power supply circuit generally includes a first transistor; a second transistor coupled to the first transistor via a first node; a third transistor coupled to the second transistor via a second node; a fourth transistor coupled to the third transistor via a third node; a capacitive element having a first terminal coupled to the first node and a second terminal coupled to the third node; an inductive element having a first terminal coupled to the second node; and a switch having a first terminal coupled to the first terminal of the inductive element, the switch having a second terminal coupled to a second terminal of the inductive element.

Abstract: A battery cell storage case according to the present invention may comprise: a case in which battery cells are stored; and a discharge unit which is electrically connected to the case, is disposed outside the case, and discharges the battery cells, wherein the case comprises: an upper case which has a hollow structure and is open on one side thereof; and a lower case which has a hollow structure and is open on the side facing the open portion of the upper case.

Abstract: Priority reversing data traffic for latency sensitive peripherals, including receiving a connection notification and parameters of a peripheral; identifying, from the parameters, that an interface type associated with the peripheral is a bulk interface, the bulk interface associated with a first communication channel between the IHS and the peripheral and having a first latency; determining, based on the bulk interface type and a data traffic priority associated with the peripheral, that the data traffic associated with the peripheral is priority-inversed; in response to a communication request by an application executing on the IHS for communication with the peripheral, determining that the data traffic associated with the peripheral is priority-inversed, and in response, placing the data traffic in a queue associated with a second communication channel defined between the IHS and the peripheral, the second communication channel having a second latency, wherein the first latency is greater than the second la

Abstract: A method and system of recharging an electric battery, include an alternation of phases of recharge at a constant current and of phases of recharge at constant voltage.

Abstract: A mobile device mounting system includes a device case and a mount. The device case includes: an insert including a rectangular bore and defining a set of undercut sections about the rectangular bore; and a first set of magnetic elements arranged in a first pattern about the rectangular bore. The mount includes: a body; a polygonal boss extending from the body and configured to insert into the rectangular bore; a set of locking jaws arranged on the polygonal boss configured to transiently mate with the set of undercut sections to constrain the polygonal boss within the rectangular bore; and a second set of magnetic elements arranged in a second pattern about the polygonal boss and configured to transiently couple to the first set of magnetic elements to transiently retain the mount against the device case and to drive the set of locking jaws toward the set of undercut sections.

Abstract: Systems and methods are described for managing charging and discharging of battery packs. In one or more aspects, a system and method are provided to minimize overcharging of battery cells of specific battery chemistries while still enabling fast charging cycles. In other aspects, a buck converter may be used to reduce a voltage of power used to charge the cells. In further aspects, a fast overcurrent protection circuit is described to address situations involving internal short circuits of a battery cell or battery pack. In yet further aspects, a bypass circuit is provided in series-connected battery packs to improve the charging of undercharged battery packs while also increasing the efficiency of the overall charging process. In other aspects, a circuit is provided that permits a controller to determine a configuration of battery packs.

Abstract: A battery charging circuit can include: a primary rectifier circuit configured to rectify an input AC voltage into a rectified voltage signal; a DC-DC converter configured to generate a charging current according to the rectified voltage signal, in order to charge a battery; a control circuit configured to adjust the charging current by controlling an operation state of the DC-DC converter according to a charging requirement, in order to make an average value of the charging current meet the charging requirement; and where the charging current is controlled to be zero when an absolute value of the input AC voltage is lower than a predetermined threshold.

Abstract: A wireless charging device includes a casing, a transmitter driving board and a transmitter coil assembly. The wireless charging device is used for charging a receiver coil of a mobile device. The transmitter driving board generates a first heat source. The transmitter driving board has a first thermal resistance. The transmitter coil assembly generates a second heat source. The transmitter coil assembly has a second thermal resistance. There is an interfacial thermal resistance between the transmitter coil assembly and the transmitter driving board. A product of a power dissipation of the second heat source and the second thermal resistance is lower than 15. The interfacial thermal resistance is higher than or equal to two times the first thermal resistance. A product of a power dissipation of the first heat source and the first thermal resistance is lower than or equal to 80.

Abstract: A battery including a first control circuit and a plurality of modules arranged in series between first and second terminals, each module including electric cells and switches coupling the cells to third and fourth terminals and a second switch control circuit. The battery includes a first data transmission bus coupling the first control circuit to each second control circuit and a second data transmission bus coupling the first control circuit to each second control circuit. The first control circuit is capable of transmitting first data to the second control circuits over the first bus at a first rate and is capable of transmitting second data to the second control circuits over the second bus at a second rate smaller than the first rate.

Abstract: A management device 50 for power storage elements is provided with a cause analysis unit 51 that, when the voltages of power storage elements B1-B4 are reduced to a prescribed level or physical quantities correlated with the voltages are reduced to prescribed values after the supply of power to the power storage elements B1-B4 has been stopped, analyzes the cause of the voltage reduction in power storage elements B1-B4 or the cause of the reduction in the physical quantities correlated with voltages to the prescribed values, on the basis of measurement data of the power storage elements B1-B4 measured after the supply of power has been stopped.

Abstract: A power control method for a charging system includes: detecting a power signal and an input voltage of the power signal; determining a charging protocol supported by the power signal; and determining whether to conduct a power switching circuit or not according to the input voltage of the power signal and the charging protocol supported by the power signal to provide power for an amplifier chip of the charging system.

Abstract: An electronic device includes a display module including a first region exposed to an outside in first and second modes and a second region extending from the first region, where the second region is partially opposite to the first region in the first mode or is partially exposed in the second mode, the second region includes a curved region in the first mode and a flat region extending from the curved region and opposite to the first region, a supporting member disposed below the display module, a case which contains the display module and the supporting member, where the first and second modes are determined based on a sliding motion of the case, and a wireless charging coil which is contained in the case and shielded by the supporting member in the first mode, and does not overlap the supporting member in the second mode.

Abstract: A multi-functional travel charger and a control system thereof are disclosed. The charger includes a charger body and a main control module communicated with wireless charging transmitting modules, a top shell and a bottom shell of the charger body are connected in a magnetic attraction/snap-fit manner, and the wireless charging transmitting modules include a mobile phone wireless charging transmitting module and an accessory wireless charging transmitting module. The control system includes a circuit control and charge/discharge management system and wireless charging transmitting modules; the accessory wireless charging transmitting module includes one or more of an earbud wireless charging transmitting module, a watch wireless charging transmitting module, and a stylus wireless charging transmitting module.

Abstract: A battery module including: a battery stack of battery cells having opposite ends to which a plurality of electrode tabs are connected; end-side bus bar assemblies formed at opposite ends of the battery stack, respectively, and electrically connecting the electrode tabs of the battery cells; and a case accommodating the battery stack and the end-side bus bar assemblies.

Abstract: This disclosure relates to an electrified vehicle having remote terminals accessible via a charging port door. An example electrified vehicle a charging port configured to couple to a plug to charge the electrified vehicle, and remote terminals. The electrified vehicle can be jump started via the remote terminals. Further, the electrified vehicle includes a charging port door moveable between a closed position, a normal open position in which the charging port is accessible such that a plug may couple to the charging port to charge the electrified vehicle, and an extended open position in which the charging port door has moved beyond the normal open position. The remote terminals are accessible when the charging port door is in the extended open position.

Abstract: The present disclosure provides a rechargeable battery for an induction garbage bin, comprising a steel shell, a battery core, an output structural component and an intermediate connection structural component, the battery core being provided in the steel shell, wherein, a lower end of a USB fixing structural part of the intermediate connection structural component is fittingly sleeved on an open end of the steel shell; a positive end of the battery core is connected with a positive tab connection point (B+) on a PCB substrate, a negative end of the battery core is connected with a negative tab connection point (B?) on the PCB substrate; the output structural component is fittingly clamped and sleeved on a USB metal part of the intermediate connection structural component; and a positive clamp output end (O+) of the electronic component is in close contact with a metal languet of a positive cap of the output structural component.

Abstract: Systems and methods are described for managing charging and discharging of battery packs. In one or more aspects, a system and method are provided to minimize overcharging of battery cells of specific battery chemistries while still enabling fast charging cycles. In other aspects, a buck converter may be used to reduce a voltage of power used to charge the cells. In further aspects, a fast overcurrent protection circuit is described to address situations involving internal short circuits of a battery cell or battery pack. In yet further aspects, a bypass circuit is provided in series-connected battery packs to improve the charging of undercharged battery packs while also increasing the efficiency of the overall charging process. In other aspects, a circuit is provided that permits a controller to determine a configuration of battery packs.

Abstract: This application is directed to an apparatus for providing electrical charge to a vehicle. The apparatus comprises a driven mass, a generator, a charger, a hardware controller, and a communication circuit. The driven mass rotates in response to a kinetic energy of the vehicle and is coupled to a shaft such that rotation of the driven mass causes the shaft to rotate. The driven mass exists in one of (1) an extended position and (2) a retracted position. The generator generates an electrical output based on a mechanical input coupled to the shaft such that rotation of the shaft causes the mechanical input to rotate. The charger is electrically coupled to the generator and: receives the electrical output, generates a charge output based on the electrical output, and conveys the charge output to the vehicle. The controller controls whether the driven mass is in the extended position or the retracted position in response to a signal received from the communication circuit.

Abstract: The present disclosure provides a charging method and a terminal. The method includes: automatically learning, by the terminal, historical data by using a machine learning algorithm, to establish a habit model of a user, and matching a current time with the usage habit model of the user to determine a current charging intention of the user, so as to determine a charging mode according to the charging intention. By means of the technical solutions, a charging requirement of a user can be effectively identified, and on-demand charging can be implemented. This improves user experience while avoiding a battery life decrease caused by frequent fast charging.

Abstract: An electrical wiring device for delivering power to multiple mobile devices including: a housing having a faceplate; a first power delivery port accessible through the faceplate; a second power delivery accessible through the faceplate; an AC/DC converter disposed in the housing and configured to receive an AC signal from a connection to a source of AC mains power and to output a DC signal; a first DC/DC converter disposed in the housing and configured to receive the DC signal and provide a first DC output signal having a first power to a first power delivery port; a second DC/DC converter disposed in the housing and configured to receive the DC signal and provide a second DC output signal having a second power to a second power delivery port; wherein the first DC output signal is different from the second DC output signal.

Abstract: A surgical system comprises a handpiece and a battery. The handpiece includes a body, a handpiece controller, and a handpiece connector with a first coupler, a handpiece voltage terminal, and a handpiece data terminal. The battery has a housing, a cell, a battery controller, and a battery connector with a second coupler to rotatably engage the first coupler, a battery voltage terminal, and a battery data terminal. The second coupler receives the first coupler at an initial radial position and permits rotation to a first secured radial position and a second secured radial position. Rotation from the initial radial position to the first secured radial position engages the voltage terminals to transmit power between the cell and the handpiece controller, and rotation to the second secured radial position engages the data terminals to communicate data between the controllers while maintaining engagement between the voltage terminals.

Abstract: A power control method for a charging system includes: detecting a power signal and an input voltage of the power signal; determining a charging protocol supported by the power signal; and determining whether to conduct a power switching circuit or not according to the input voltage of the power signal and the charging protocol supported by the power signal to provide power for an amplifier chip of the charging system.

Abstract: Eyewear including a see-through display, a battery, and a frame forming at least one electrical contact for connection to a battery charger for battery charging. The electrical contact is large compared to the size of a battery charging contact to allow easy alignment. The frame may be tied to ground in one example, and to a positive potential in another example. In another example, the frame may be formed into a left portion that is electrically isolated from a right portion. The left portion has a contact coupled to a ground electrode of the battery and is configured to connect to a ground electrode of the battery charger. The right portion has a contact coupled to a positive electrode of the battery and is configured to connect to a positive potential of the battery charger.

Abstract: A battery pack includes: a connector holder that is fixed to an exterior case and has two main surfaces that include a first main surface exposed through an opening of the exterior case; a floating connector connected with a center of the connector holder in such a manner that the floating connector floats in such a manner that an orientation or a position of the floating connector is variable upward, downward, leftward, and rightward; a lead wire fixed to an inner surface of the floating connector, the lead wire extending through an inside of the exterior case, and the lead wire connecting floating connector with a circuit board; and a positioning buffer that pushes the floating connector, and positions the floating connector at a predetermined original state when an external force is not applied to the floating connector.

Abstract: A charging dock, an electronic product, a charging system and a charging method are provided. The charging dock includes a housing, a first charging terminal, a first magnetic device, a first detection device and a first control circuit. The first charging terminal, the first magnetic device, the first detection device and the first control circuit are in the housing. The first magnetic device is to attract the charging plug near the first magnetic device to enable the charging plug to move in a direction towards the first charging terminal. The first control circuit is to control the first charging terminal to be energized when the first detection device detects that the first charging terminal is electrically coupled to the charging plug.

Abstract: A control apparatus comprises: a first acquisition unit configured to acquire information indicating charging and discharging performance of an electric power device and environmental information on the electric power device; a second acquisition unit configured to acquire information indicating a characteristic of operation of charging and discharging the electric power device; a correction unit configured to correct the information indicating the charging and discharging performance of the electric power device on the basis of the environmental information; and a control unit configured to control the operation of charging and discharging the electric power device according to a management plan, the management plan being based on the information indicating the charging and discharging performance corrected by the correction unit and the information indicating the characteristic of the operation of charging and discharging the electric power device.

Abstract: Systems and methods are described for managing charging and discharging of battery packs. In one or more aspects, a system and method are provided to minimize overcharging of battery cells of specific battery chemistries while still enabling fast charging cycles. In other aspects, a buck converter may be used to reduce a voltage of power used to charge the cells. In further aspects, a fast overcurrent protection circuit is described to address situations involving internal short circuits of a battery cell or battery pack. In yet further aspects, a bypass circuit is provided in series-connected battery packs to improve the charging of undercharged battery packs while also increasing the efficiency of the overall charging process. In other aspects, a circuit is provided that permits a controller to determine a configuration of battery packs.

Abstract: A method of operating a medical device comprises electrically connecting a power device to the medical device. The method further comprises sensing at least one characteristic of the medical device with the power device. The method further comprises adjusting or maintaining one or more characteristics of an electrical connection feature of the power device according to the at least one observed characteristic such that the electrical connection feature of the power device is operationally compatible with an electrical connection feature of the medical device. The method further comprises operating the power device according to an operational profile associated with the medical device.

Abstract: A charging station for charging a plurality of electric vehicles, in particular electric cars, comprising: a supply device, in particular for connecting to an electricity supply grid, for supplying the charging station with electric power, a plurality of charging terminals each for charging at least one electric vehicle, and each charging terminal comprises a supply input for drawing electric power from the supply device, a charging output having one or more charging terminals each for outputting a charging current for respectively charging a connected electric vehicle, and at least one DC current controller, arranged between the supply input and the charging output, for generating a respective controlled current from the electric power from the supply device, wherein each charging current (IL1, IL2) is formed from a controlled current or from a plurality of controlled currents (IS1, IS2, IS3), and wherein the charging terminals are connected to one another at exchange terminals by way of electrical exchange

Abstract: A method of controlling a battery including a first control circuit and a plurality of modules arranged in series between first and second terminals, each module including electric cells and switches and a second switch control circuit, the battery further including at least one first data transmission bus coupling the first control circuit to each second control circuit, the method including the transmission, by the first control circuit to the second control circuits, of first data representative of an electric cell configuration to be obtained to follow a set point for the delivery of a voltage and/or of a current between the first and second terminals, the second control circuits connecting or disconnecting the electric cells based on said first data and on a classification of the priorities of the electric cells.

Abstract: A wireless charging system for recharging batteries in a medical environment includes a charging station. The charging station may include an opening to receive batteries and an outlet for dispensing charged batteries, wherein the outlet comprises a slot in a front cover. The charging station also includes a wireless power transmitter having a transmitting antenna.

Abstract: Compact light-weight on-board three-port power electronic system built in various configurations of triple-active-bridge-derived topologies, including modular implementations, with control strategies capable of bi-directional power transfer among the three ports of the power electronic system, including simultaneous charging of a high voltage (HV) battery and a low voltage (LV) battery from a single phase power grid or a three-phase power grid with minimized reactive power and active circulating current, with ensured soft-switching for MOSFET devices, and with enhanced synchronous rectification and reduced power losses.

Abstract: A battery module including a plurality of prismatic secondary battery cells, each of the battery cells including a bottom surface, and a housing for accommodating the battery cells and including a housing floor defining integral coolant channels for passage of coolant, the integral coolant channels being in thermal contact with the bottom surfaces of the battery cells.

Abstract: Devices and methods for sharing power between power sources are disclosed. The power sources may be internal to an electronic device, external to the electronic device, or both. An electronic device may include a power source, a switch circuit, a processor, and a power management integrated circuit (PMIC). The processor may determine a load current estimate. The load current estimate may be based on a device setting, an external temperature, or both. The processor may determine a power source voltage, an external power source voltage, or both. The processor may determine a power source current, an external power source current, or both. The PMIC may set an output power source current of the power source. The PMIC may set an output external power source current of the external power source.

Abstract: A mobile device wirelessly communicates with a vehicle device. The mobile device includes a receiving unit, a response signal generation unit, a transmission unit, a charging unit, and a charge state determination unit. The receiving unit receives a response request signal transmitted from the vehicle device. The response signal generation unit generates a response signal in response to the response request signal. The transmission unit transmits the response signal. The charging unit charges a built-in battery with an electric power supplied wirelessly or through wire from a power supply device. The charge state determination unit determines whether the charging unit charges the built-in battery. The mobile device is configured not to transmit the response signal, in a situation where the charge state determination unit determines that the charging unit is charging the built-in battery.

Abstract: Systems and methods are described for managing charging and discharging of battery packs. In one or more aspects, a system and method are provided to minimize overcharging of battery cells of specific battery chemistries while still enabling fast charging cycles. In other aspects, a buck converter may be used to reduce a voltage of power used to charge the cells. In further aspects, a fast overcurrent protection circuit is described to address situations involving internal short circuits of a battery cell or battery pack. In yet further aspects, a bypass circuit is provided in series-connected battery packs to improve the charging of undercharged battery packs while also increasing the efficiency of the overall charging process. In other aspects, a circuit is provided that permits a controller to determine a configuration of battery packs.

Abstract: A battery pack in one aspect of the present disclosure includes a communication terminal and a detector, and supplies electric power to an external device. The communication terminal receives a first signal, a second signal, and a third signal. The first signal has a first potential, the second signal has a second potential, and the third signal has a third potential. The first potential, the second potential, and the third potential are different from one another. The detector determines a potential at the communication terminal, to thereby detect the first signal, the second signal, or the third signal in accordance with the determined potential.

Abstract: A method to charge a personal-protection-device energy store for operating a personal protection device of a vehicle. The method includes a step of reading in a voltage value of a source energy store of the vehicle. In addition, the method includes a step of ascertaining a charging current for charging the personal-protection-device energy store with power from the source energy store, the charging current being ascertained, using the voltage value read in; and using the charging current for charging the personal-protection-device energy store.

Abstract: The present disclosure discloses a charging apparatus. The charging apparatus comprises a power source module, a main control circuit, a voltage booster circuit, an adjusting circuit, and an output port. The charging apparatus is configured to charge a vehicle battery or other consumers through the output port. The power source module is electrically connected to the main control circuit and the voltage booster circuit. The main control circuit is electrically connected to the adjusting circuit and the voltage booster circuit. The main control circuit is configured to output an adjusting signal to the adjusting circuit. The adjusting circuit controls the voltage booster circuit to output a first or second output voltage to the output port, according to the adjusting signal. The second output voltage is greater than the first output voltage. The present disclosure provides a plurality of voltages to meet the vehicle battery.

Abstract: A lithium ion secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution containing a polycyclic aromatic compound.

Abstract: Systems and methods are described for managing charging and discharging of battery packs. In one or more aspects, a system and method are provided to minimize overcharging of battery cells of specific battery chemistries while still enabling fast charging cycles. In other aspects, a buck converter may be used to reduce a voltage of power used to charge the cells. In further aspects, a fast overcurrent protection circuit is described to address situations involving internal short circuits of a battery cell or battery pack. In yet further aspects, a bypass circuit is provided in series-connected battery packs to improve the charging of undercharged battery packs while also increasing the efficiency of the overall charging process. In other aspects, a circuit is provided that permits a controller to determine a configuration of battery packs.

Abstract: Disclosed are embodiments to provide a multi-battery energy storage device. One embodiment comprises a first battery and a second battery, with a first circuit branch coupling a positive side of the first battery to a positive side of the second battery, a second circuit branch coupling a positive side of the first battery to a negative side of the second battery, a third circuit branch coupling the negative side of the first battery to the negative side of the second battery, and multiple switchable devices configured to control flow of current through corresponding branches. Other embodiments comprise other configurations and operations.