Abstract: The present invention generally relates to a powered mobile display device stand for use in locations without available or reliable electrical power. A plate designed to hold a display device is attached to an articulating neck. The neck is affixed to a mobile base containing therein a battery, inverter, charger, power input and power output. The plate may articulate to adjust viewing angle of the display device. And the neck may articulate to adjust the viewing height of the display device. The battery may be sized to provide power to the display device, as well as additional peripherals. Computer software is optionally included to control and monitor all functionality of the system using a display device such as a touchscreen monitor.

Abstract: A system incorporating a smartphone and an add-on device coupled to each other via combined data/power interface, the smartphone having a rechargeable battery connected to battery protection circuitry and the add-on device optionally having a rechargeable battery connected to battery protection circuitry as well, the combined data/power interface having one or more data pins for transferring data between the smartphone and the add-on device, one or more regulated power delivery pins, and one or more protected-battery power delivery pins, wherein the regulated power delivery pins are used to charge the battery of the smartphone from an external charger coupled to the add-on device, the batteries are connected to the battery protection circuitries that is configured to protect the battery by cutoff or limit the current or voltage on the battery electrodes, and the protected-battery power delivery pins are connected to the battery protection circuitries of the smartphone or add-on device.

Abstract: A charging method for a secondary battery including a lithium-supplementing material. The method includes acquiring a first state of health of the secondary battery in response to the secondary battery being at a preset charging node, activating the lithium-supplementing material in response to the first state of health being less than or equal to a first threshold to supplement lithium for the secondary battery, performing a charging process on the secondary battery, determining a second state of health of the secondary battery based on a working parameter of the secondary battery in the charging process, and charging the secondary battery in response to the second state of health being greater than a second threshold.

Abstract: A method comprises an active discharge manager, integrated with a smart cable, detecting a connection of the smart cable to a battery and/or a discharge-load and detecting a connection coupling the battery and the discharge-load. Responsive to the detecting the connections, the active discharge manager determines a transfer status of the battery and the discharge-load. Based on the transfer status, the active discharge manager initiates a discharge process that transfers energy from the battery to the discharge-load. The active discharge-manager can determine a second transfer status of the battery and the discharge-load and, based on the second transfer status, terminate or modify the discharge process. The smart cable can be re-usable, and the discharge-load can make productive use of the energy transferred to the discharge-load. A system can comprise a battery, a discharge-load, and a smart cable to perform the method to discharge the battery into the discharge-load.

Abstract: A system and method for digital management and control of power conversion from battery cells. The system utilizes a power management and conversion module that uses a CPU to maintain a high power conversion efficiency over a wide range of loads and to manage charge and discharge operation of the battery cells. The power management and conversion module includes the CPU, a current sense unit, a charge/discharge unit, a DC-to-DC conversion unit, a battery protection unit, a fuel gauge and an internal DC regulation unit. Through intelligent power conversion and charge/discharge operations, a given battery type is given the ability to emulate other battery types by conversion of the output voltage of the battery and adaptation of the charging scheme to suit the battery.

Abstract: Provided is an energy storage system including: an external power input unit receiving uninterrupted external power; a battery storing electric power; a power adjustment device adjusting the uninterrupted external power and the power of the battery, the battery including a battery module with one or more battery cells; a battery management system; a main switch disposed on a power path between the battery module and the battery management system and a path between the battery module and the power adjustment device; and a wake-up relay receiving a wake-up signal from the power adjustment device and transmitting the wake-up signal to the battery management system.

Abstract: A computer includes a processor and a memory storing processor-executable instructions. The processor is programmed to prevent a traction battery from providing power to a vehicle powertrain below a charge threshold, and then, upon one of (a) receiving an acceleration demand above an acceleration threshold and (b) predicting that a planned maneuver classified as high acceleration will occur within a time threshold, permit the traction battery to provide power to the vehicle powertrain below the charge threshold.

Abstract: Various embodiments are directed to battery unit for use with surgical instruments. The battery units may comprise a plurality of cells and include a translatable discharge drain. When attached to the surgical instrument, the discharge drain may electrically connect an anode of the battery unit to a cathode of the battery unit, for example, via a resistive element in order to drain the battery unit.

Abstract: The disclosure relates to a battery management apparatus, a vehicle having the same, and a method of controlling the vehicle. A method of controlling the vehicle having a motor, an engine, and a battery includes detecting respective voltage values of the plurality of cells provided in the battery; identifying a maximum voltage value and a minimum voltage value among the voltage values of the plurality of cells; obtaining a voltage deviation value between the identified maximum voltage value and the minimum voltage value; obtaining a deterioration rate of the battery; obtaining a power limit value of the battery based on at least one of the voltage deviation value or the deterioration rate of the battery; obtaining a final power limit value based on the obtained power limit value and a preset weight; and controlling a discharge of the battery based on the obtained final power limit value.

Abstract: An energy storage apparatus comprising: one or more energy storage devices; and an outer covering which houses the one or more energy storage devices, wherein the outer covering has a discharge portion forming a discharge path which discharges a substance generated in an inside of the energy storage apparatus toward outside of the outer covering in a first direction, and an inner wall surface of the discharge portion includes a first wall surface inclined with respect to the first direction, and the discharge path is formed by the discharge portion such that a cross-sectional area of the discharge path increases towards an outlet side of the discharge portion.

Abstract: In accordance with one or more embodiments, a waveguide system includes a transmission device configured to send and receive guided electromagnetic waves that propagate along a surface of a power line without requiring an electrical return path. The waveguide system further includes a magnetic core that surrounds the power line, a first winding around the magnetic core that generates a supply current in response a transmission current flowing through the power line and a power supply that converts the supply current to a supply voltage that powers the transmission device. The power supply automatically stabilizes power consumption by the transmission device in response to variations in the supply current caused by variations in the transmission current flowing through the power line.

Abstract: In one embodiment, a battery backup unit (BBU) cut-off and recharge circuit includes: a first transistor, a power entry connection connected to a main power supply, where power from the power entry connection flows to application circuits for an electronic device, and the first transistor is positioned between a BBU and the power entry connection, and a microcontroller, where the microcontroller is operative to: detect a loss of power from the main power supply, turn on the first transistor to enable the BBU to discharge through the power entry connection to application circuits, detect a status of charge (SOC) for the BBU, and upon detecting that the SOC is under a predefined threshold, set the BBU cut-off and recharge circuit to a lockdown state by turning off the first transistor.

Abstract: A parameter estimation device includes: a voltage acquisition unit; a current acquisition unit; a parameter estimation unit; an internal resistance deriving unit; and a determination unit configured to determine, on the basis of a result of comparison between the internal resistance estimated by the parameter estimation unit and the internal resistance derived by the internal resistance deriving unit, whether or not to replace parameters of the secondary battery with the plurality of parameters estimated by the parameter estimation unit.

Abstract: The present disclosure discloses a charging control system, which includes: a master device, including a first USB interface and a first charging management circuit; at least one slave device, including a second USB interface and a second charging management circuit; a gating control circuit, which is arranged in the master device or the slave device, wherein an input terminal of the gating control circuit is coupled to the first USB interface and the second USB interface, and an output terminal of the gating control circuit is coupled to the first charging management circuit and the second charging management circuit to select and control a charging USB interface of the first charging management circuit and a charging USB interface of the second charging management circuit. Through the above mentioned way, multiple charging modes of the master device and the slave device may be implemented without software support.

Abstract: In a power storage system, a management device calculates a state of power (SOP) of a whole of a plurality of power storage blocks connected in parallel based on an SOP of each of the plurality of power storage blocks to specify the calculated SOP of the whole for an upper limit level of power or current for at least one of charging and discharging controlled by a power converter. When at least one of a plurality of switches is turned off to disconnect at least one (30) of the plurality of power storage blocks, the management device calculates an SOP of a whole of the remaining power storage blocks based on a deviation in current between each of the remaining power storage blocks to determine an upper limit level of power or current flowing into the power converter.

Abstract: An electrolyte solution for a potassium ion battery or a potassium ion capacitor, the electrolyte solution comprising at least one potassium salt compound selected from the group consisting of potassium bis(trifluoromethanesulfonyl)amide and potassium bis(fluorosulfonyl)amide and at least one solvent selected from the group consisting of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, ethylene carbonate, and propylene carbonate, in which a concentration of the potassium salt compound in the electrolyte solution is from 1.5 mol/kg to 12.0 mol/kg.

Abstract: Method for operating a charging station for electric vehicles wherein a switching state of at least one fuse arranged between a grid connection and a charging cable connection is monitored and with the aid of a contact state a connection to and a separation from the charging cable connection by a charging cable is monitored. The charging station can continue to be kept in operation in the case of a fault at the vehicle side when an opening of the fuse occurring during a connection of the charging cable to the charging cable connection is detected with the aid of the monitored switching state and in the case of an opening detected in this manner following a detected separation of the charging cable from the charging cable connection, the fuse is autonomously closed.

Abstract: A controller for controlling a charging current to a lithium-ion secondary battery controls the charging current so that lithium expected to dissolve after a stop of charging is permitted to deposit on an anode of the lithium-ion secondary battery. For example, the controller controls the charging current so that the charging current does not exceed a predetermined upper limit value. If a predetermined permission condition is satisfied, the controller permits the lithium expected to dissolve after the stop of charging to deposit on the anode of the lithium-ion secondary battery by permitting the upper limit value to become larger than a Li deposition limit value in a predetermined permission period.

Abstract: A battery system includes a traction battery, a traction battery controller, and a backup controller. The traction battery powers a high-voltage domain. The traction battery controller may be powered by a low-voltage domain that is separated from the high-voltage domain. The traction battery may be configured to disable cell balancing of the traction battery after expiration of a main timer. The backup controller may be powered by and within the high-voltage domain. The backup controller implements a backup timer, that includes a non-processor logic circuit, and is configured to disable cell balancing after expiration of the backup timer.

Abstract: An electronic device includes a power receiving unit that receives power from a power supply apparatus, a type determination unit that determines a type of the power supply apparatus, a capability determination unit that determines a power supply capability of the power supply apparatus, and a control unit. The control unit limits or stops power to be received from the power supply apparatus if the type of the power supply apparatus is determined to be a first type and the power supply capability of the power supply apparatus is determined to be a second power supply capability higher than a first power supply capability that corresponds to the first type.

Abstract: An apparatus and a method for managing power consumption for each power consumption element in an electronic device and updating a power profile is disclosed. The electronic device estimates current power consumption of the electronic device based on unit power consumption corresponding to each target hardware component set in the power profile and monitors whether an update of the power profile is required. If it is determined that the update of the power profile is required, the electronic device may update the power profile corresponding each target hardware component by consumption estimated in accordance with each target hardware component and consumption measured in accordance with each target hardware component.

Abstract: Systems, methods, and computer-readable media are described for addressing the unit commitment problem in a power grid by providing a communication-free control framework according to which each power generating unit in the power grid determines its own operating schedule for turning on or off based solely on local measurements.

Abstract: Described herein are aqueous organic redox flow batteries that include a first redox active material that can include a metallocene or a salt thereof, and a second redox active material that can include a viologen or a salt thereof. The aqueous organic redox flow batteries may further include a first aqueous electrolyte, a second aqueous electrolyte, and a separator between the first and second aqueous electrolytes. In addition, disclosed herein are methods of making the metallocene and viologen compounds.

Abstract: An active discharge circuit discharges an X capacitor and includes a sensor circuit that generates a sensor signal indicative of an AC voltage at the X capacitor. A processing unit generates a reset signal as a function of a comparison signal. A comparator circuit generates the comparison signal by comparing the sensor signal with a threshold. A timer circuit sets a discharge enable signal to a first logic level when the timer circuit is reset via a reset signal. The timer circuit determines the time elapsed since the last reset and tests whether the time elapsed exceeds a given timeout value. If the time elapsed exceeds the given timeout value, the timer circuit sets the discharge enable signal to a second logic level. A dynamic threshold generator circuit varies the threshold of the comparator circuit as a function of the sensor signal.

Abstract: A monitoring apparatus is provided for monitoring voltages of a plurality of battery cells. The battery cells are electrically connected in series with each other and each include a pair of electrode terminals. The monitoring apparatus includes a flexible substrate, a monitoring circuit and a plurality of noise removal elements. The flexible substrate has a plurality of wiring patterns formed thereon. The wiring patterns are electrically connected with the electrode terminals of the battery cells. The monitoring circuit is electrically connected with the electrode terminals of the battery cells via the wiring patterns and configured to monitor the voltages of the battery cells inputted thereto via the wiring patterns. The noise removal elements are provided in monitoring circuit-side parts of the wiring patterns to remove noise inputted to the wiring patterns.

Abstract: A charge management method includes generating and storing a charge schedule related to an electric energy for charging a vehicle within an amount of suppliable electric power for charging said vehicle located in a region, wherein said vehicle includes a rechargeable battery. The method further includes storing an identification number of said vehicle in said region by an EV controlling center. The method further includes determining a propriety of charging said vehicle at a current time and location based on said charge schedule in response to detection of a signal indicating a start of a charging process of said rechargeable battery from said vehicle having said identification number.

Abstract: Disclosed are an apparatus and method for estimating a state-of-charge of a zinc flow battery by measuring a concentration of zinc ions contained in an electrolyte through an open-circuit voltage (OCV). The apparatus according to embodiments of the present invention can estimate effectively the state-of-charge of the zinc flow battery from the concentration of zinc ions measured through the OCV of the working electrode with respect to the reference electrode when the measuring electrodes are installed in the cathode electrolyte tank or the anode electrolyte tank.

Abstract: An induction charging system (100) includes: (i) an induction charging station (10) having: an emitting primary induction coil (14); a receiving secondary induction coil (18); and a primary dock (20) for a primary chargeable device; (ii) a primary chargeable device (24) configured to reversibly engage the primary dock and comprising a receiving induction coil (26); and (iii) a secondary device in communication with the secondary induction coil and configured to receive energy from the secondary induction coil, wherein the secondary induction coil is configured to receive excess energy from the primary induction coil without interfering with the receiving induction coil.

Abstract: High power lithium-ion batteries are disclosed. Such batteries may be used, for example, as the sole electric starter motor power sources for automotive vehicles powered by multi-cylinder engines with reciprocating pistons when the vehicles are to be operated in an engine start-stop mode to conserve fuel. Such batteries typically utilize non-aqueous solutions of lithium salts, such as LiPF6 or LiBF4, in combination with durable lithium intercalating electrodes. In accordance with this disclosure the performance of the battery's electrolyte and cells over a wide ambient temperature range is enhanced by a mixture of five miscible solvents formed of lower alkyl moieties. The quinary solvent mixture comprises two cyclic alkyl carbonates, two linear alkyl carbonates, and with a major portion of an alkyl ester.

Abstract: A flow battery includes a first liquid, a second liquid, a first electrode immersed in the first liquid, a second electrode being a counter electrode of the first electrode and immersed in the second liquid, and an isolation unit separating the first electrode and the first liquid from the second electrode and the second liquid. Lithium is dissolved in at least one of the first liquid and the second liquid. The first liquid and the second liquid have a property of emitting solvated electrons of lithium and dissolving the lithium as a cation.

Abstract: Titanium catecholate complexes can be desirable active materials for flow batteries and other electrochemical energy storage systems, particularly when incorporated in aqueous electrolyte solutions. It can be desirable to avoid introducing certain organic solvents and/or extraneous salts into aqueous electrolyte solutions. Methods for synthesizing titanium catecholate complexes that can help avoid the unwanted introduction of organic solvents and/or extraneous salts into aqueous electrolyte solutions can include: providing an aqueous solution containing a catechol compound, reacting a titanium reagent with the catechol compound in the aqueous solution to form an intermediate titanium catecholate complex, isolating the intermediate titanium catecholate complex as a solid or slurry, and reacting a ligatable compound with the intermediate titanium catecholate complex in the presence of a base to produce a salt form titanium catecholate complex containing at least one additional ligand.

Abstract: The present invention relates to an electronic circuit for harvesting energy from ultra-low power sources, said circuit comprising a capacitor module (1), a microcontroller (2), two analog switches (3 and 7), an auxiliary battery module (4), a terminal (5), and an operating mode module (6). The circuit is characterised in that: at least two sources (FE) from a plurality of sources (FE) are connected to the capacitor module (1); and the microcontroller (2) transmits the RC digital signals [1.4] at the capacitor module (1) to the first set of analog switches and changes from an idle state to an active state.

Abstract: A system and method of wireless power transfer using a power converter with a bypass mode includes a power converter. The power converter includes a pulsed switch, a capacitor configured to supply a drive voltage to the pulsed switch, a first circuit configured to charge the capacitor when the power converter operates in a switched mode of operation, and, a second circuit configured to charge the capacitor when the power converter operates in a bypass mode of operation.

Abstract: A battery includes a first insulator, a first electrode layer, and a first counter-electrode layer. The first counter-electrode layer is a counter electrode for the first electrode layer. The first insulator includes a first electrolyte portion, a second electrolyte portion, and a first bent portion. The first bent portion is positioned between the first electrolyte portion and the second electrolyte portion. The first electrode layer is disposed in contact with the first electrolyte portion. The first counter-electrode layer is disposed in contact with the second electrolyte portion. The first insulator is bent at the first bent portion, and thereby the first electrode layer and the first counter-electrode layer are positioned facing each other.

Abstract: A current sense method comprises generating a voltage across a first current mirror of a current sense apparatus, the voltage being proportional to a current flowing through the current sense apparatus when the current is greater than a predetermined current value and applying a minimum drain-to-source voltage limiter to the first current mirror of the current sense apparatus when the current is less than the predetermined current value, wherein, as a result of applying the minimum drain-to-source voltage limiter to the first current mirror, the voltage across the first current mirror is clamped to a predetermined voltage value.

Abstract: An electronic device according to various exemplary embodiments of the present invention may include one or more switches, one of more sub-systems, and an interface control unit electrically coupled with the one or more sub-systems and the one or more switches. The interface control unit is configured to: detect a coupling of an external device to the electronic device, identify a type of the coupled external device, when the external device is identified as a current detecting device, generate a first control signal for turning off power to the one or more sub-systems, and a second control signal for setting a first path to supply the one or more sub-systems with power from the current detecting device, and transmit the first control signal to the one or more sub-systems and the second control signal to the one or more switches.

Abstract: An apparatus monitors the state of charge (SOC) of a flow battery system. The monitoring method include determining SOCs of at least two pairs of different monitoring positions. A pair of monitoring position may be located inside of an anode electrolyte storage tank (2) and inside of a cathode electrolyte storage tank (3), or inside of an anode electrolyte outlet pipeline (6) of a stack and inside of a cathode electrolyte outlet pipeline (7) of the stack, or inside of an anode electrolyte inlet pipeline (8) of the stack and inside of a cathode electrolyte inlet pipeline (9) of the stack. The SOCsum of the flow battery system is acquired according to the SOCs corresponding to different pair of monitoring positions, respectively. The method ensures acquiring an SOC monitoring result timely and accurately.

Abstract: The present application relates to a heating control method and a heating control device for a battery structure, and a battery system. The heating control method includes steps of: S10, detecting a temperature value T of the battery structure; S20, judging whether the temperature value T meets a first heating condition, if yes, going to step S30; S30, controlling a positive electrode terminal to be connected with a negative electrode terminal to form short circuit, so as to heat the battery structure using heat generated by a short circuit current. When the first condition is met, the positive and negative terminals are connected to form short circuit, the heat generated by the short circuit current rapidly dissipates in the battery structure, so that the battery structure can be heated rapidly, which decreases the difference between internal and external temperature of the battery structure when adopting conventional heat conduction method.

Abstract: A discharging control system for a battery includes temperature sensing means configured to provide a temperature value associated with the battery, voltage sensing means configured to provide a voltage value associated with the battery, pressure sensing means configured to provide a pressure value associated with an internal portion of the battery, and a controller.

Abstract: The invention provides a method for estimating a battery capacity of an electronic device. When a current or an average current of the battery is zero, a reference capacity is inquired from a look-up table based on a voltage of the battery. When a previously remaining capacity is greater than a reference capacity, a deduction process of a self-consumable capacity is performed one or more times for a previously recorded remaining capacity to obtain a new recorded remaining capacity smaller than the reference capacity. When the current of the battery is less than zero, a deduction process of a count capacity of discharging is performed one or more times for the previously recorded remaining capacity until a power of the battery is exhausted to obtain a first offset capacity. The first offset capacity is deducted from a previously recorded full charge capacity to estimate a new full charge capacity.

Abstract: An apparatus and method for estimating state information of a battery are provided. The apparatus may estimate the state information from information, obtained by classifying and preprocessing battery information measured by a battery management system (BMS), using a pre-trained battery degradation model.

Abstract: Various embodiments are directed to battery packs for use with surgical instruments. The battery packs may comprise a plurality of cells and at least a portion of the plurality of cells may not be electrically connected to one another. The battery packs may comprise a switch or other mechanism for interconnecting the plurality of cells and may also comprise, or be used in conjunction with, a discharge switch or plug configured to electrically connect an anode of the battery pack to a cathode of the battery pack, for example, via a resistive element.

Abstract: Disclosed are a battery module and a battery pack including the same. The battery module includes a frame; and a plurality of battery cells disposed at the frame, and the plurality of battery cells are arranged in a single layer with respect to the frame.

Abstract: A power reset circuit is provided. The power reset circuit has a first terminal coupled to a first power storage element and a second terminal coupled to a second power storage element and a load and includes a discharging control circuit and a switching control circuit. The discharging control circuit induces a short circuit between the second terminal and the ground terminal when a supply voltage at the second terminal is lower than a reset voltage to provide a first discharging path. The switching control circuit provides a conduction path between the first and second terminals when the supply voltage is higher than an end-of-discharging voltage lower than the reset voltage. During a period when the supply voltage is lower than the end-of-discharging voltage, the switching control circuit cuts off the conduction path and provides a second discharging path between the first terminal and the discharging control circuit.

Abstract: An apparatus monitors the state of charge (SOC) of a flow battery system. The monitoring method include determining SOCs of at least two pairs of different monitoring positions. A pair of monitoring position may be located inside of an anode electrolyte storage tank (2) and inside of a cathode electrolyte storage tank (3), or inside of an anode electrolyte outlet pipeline (6) of a stack and inside of a cathode electrolyte outlet pipeline (7) of the stack, or inside of an anode electrolyte inlet pipeline (8) of the stack and inside of a cathode electrolyte inlet pipeline (9) of the stack. The SOCsum of the flow battery system is acquired according to the SOCs corresponding to different pair of monitoring positions, respectively. The method ensures acquiring an SOC monitoring result timely and accurately.

Abstract: A system and method for measuring a voltage of electrochemical cells of a pack. The system includes circuit elements individually associated with respective electrochemical cells of the pack and having electrical characteristics that are different such that individual electrochemical cells can be distinguished from one another. The system also includes a measurement circuit configured to measure the voltage of the electrochemical cells and to identify an electrochemical cell being measured based on an electrical characteristic of a circuit element associated with the electrochemical cell. Various self-diagnostic techniques are described, as well as techniques for measuring sense resistance, reducing sense resistance, and measuring changes in voltage of a cell over time.

Abstract: A battery state detector includes a main unit configured to detect a state of one battery assembly in a battery pack storing therein a plurality of battery assemblies each including a plurality of battery cells arranged in rows, a subunit configured to detect a state of a battery assembly in the battery pack other than the battery assembly that is a detection target of the main unit, and a first communication line that connects the main unit with the subunit. The main unit is connected to a controller configured to control the battery pack via a second communication line that is separate from the first communication line.

Abstract: Embodiments herein provide a method and electronic device for detecting an internal short circuit in a battery. The method includes obtaining, by a battery management system, battery gauge data. Further, the method includes estimating, by the battery management system, an internal resistance of the battery using the battery gauge data. Furthermore, the method includes detecting, by the battery management system, the internal short circuit in the battery by comparing a change in the internal resistance with a pre-defined resistance change threshold value.

Abstract: A power tool includes: a secondary battery; a drive unit; a detecting unit; and a control unit. The secondary battery has positive and negative terminals across which a battery voltage is developed. The drive unit is connected to the secondary battery. The detecting unit is configured to detect a current value and a voltage value supplied from the secondary battery to the drive unit. The control unit is configured to control an effective voltage and an effective current applied to the drive unit depending on a load imposed thereon to fall within an allowable power dissipation value.

Abstract: An electrical circuit for driving at least one electric motor, the at least one motor having at least one set of phases windings. The electrical circuit is arranged as at least one lane comprising a motor drive circuit that is operable in use to supply drive voltages to one of the sets of phase windings of the motor. A reverse battery protection circuit is provided for at least one lane and is located in either a feed to the motor drive circuit from a power supply or in a return path from the motor drive circuit to the power supply. The reverse battery protection circuit comprises a switch which is normally open when the battery is disconnected and which remains open in the event that the battery is connected in error with a reverse polarity to the drive circuit.