Method and system for automatically detecting a voltage of a battery

Embodiments disclosed herein provide methods and systems for auto-voltage detect chargers. One disclosed method comprises the steps of determining a condition of a battery based at least in part on a measured response to a predetermined test charge; and determining a voltage rating of the battery based at least in part on the condition of the battery and a response to a precharge process.

FIELD OF THE INVENTION

The present invention relates to battery chargers, and more particularly to automatic voltage detection chargers.

BACKGROUND OF THE INVENTION

Conventional methods for battery charging are cumbersome, time-consuming, and error-prone. Current battery chargers capable of charging batteries of different voltages require users to manually select a voltage rating of the battery to be charged in order for the battery to be properly charged, and not damaged by the charging process. If a user selects a wrong battery voltage rating, the battery may not be properly charged, and the battery and/or the charger may be permanently damaged.

Manual selection of the battery voltage, however, is subject to the user actually knowing the proper battery voltage rating, and correctly selecting the voltage rating on the battery charger itself. Because rechargeable batteries can have different voltage ratings, even among batteries with the same form factor, the voltage rating of a specific battery may not be obvious to a user. Furthermore, physically selecting a voltage rating on a battery charger may be hampered by environmental conditions, such as darkness or moisture, or deterioration of the controls on the battery charger itself.

Thus there is a need for chargers that automatically detect the voltage of a battery.

SUMMARY OF THE INVENTION

Embodiments disclosed herein provide methods and systems for auto-voltage detect chargers. For example, one embodiment comprises a method comprising the steps of determining a condition of a battery based at least in part on a response to a predetermined test charge; and determining a voltage rating of the battery based at least in part on the condition of the battery and a response to a precharge process.

Other embodiments and further details on various aspects of the invention, including apparatus, systems, methods, kits, articles, assemblies, and the like which constitute part of the invention, will become more apparent upon reading the following detailed description of the exemplary embodiments and viewing the drawings. It is to be understood that the invention is not limited in its application to the details set forth in the following description, figures, and claims, but is capable of other embodiments and of being practiced or carried out in various ways.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS AND METHODS

Reference will now be made in detail to exemplary embodiments and methods of the invention as illustrated in the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the drawings. It should be noted, however, that the invention in its broader aspects is not limited to the specific details, representative devices and methods, and illustrative examples shown and described in connection with the exemplary embodiments and methods.

In one exemplary method for auto-voltage detection, a battery charger includes a microprocessor, and is configured to monitor a plurality of characteristics of a battery, including the terminal voltage of the battery, the temperature of the battery, and a current supplied by the battery. The exemplar process for determining the voltage rating of the battery comprises a test charge phase and a precharge phase. During the test charge phase, the battery charger applies a predetermined test charge of 2 amps to a battery for 1 second. After the predetermined test charge, the battery charger measures the initial terminal voltage of the battery, and the microprocessor determines a condition of the battery based at least in part on the voltage response. The microprocessor determines the condition of the battery, such as fully charged, ready to be charged, or error/faulty, by comparing the initial terminal voltage of the battery against a series of threshold levels. A battery ready to be charged may respond to the test charge with an initial terminal voltage between a minimum and a maximum voltage threshold.

When the microprocessor determines that a battery condition is ready to be charged, then the precharge phase is initiated. The precharge phase begins by applying a small precharge current, such as 2 amps, to the battery, for a predetermined period of time, such as 60 or 120 seconds. The battery charger then waits (i.e. applies no current) for a second predetermined period of time (e.g. 30 or 60 seconds). The battery charger repeats this precharge cycle, and applies a 2 amp precharge current for 60 or 120 seconds, and applies no current (or a negligible current) for 30 or 60 seconds.

Finally, the charger measures the post precharge voltage of the battery. By comparing the post precharge voltage of the battery to a series of threshold levels, the microprocessor determines a voltage rating of the battery based at least in part on the charge-ready condition of the battery and the post-precharge voltage of the.

Referring now to the drawings in which like numerals indicate like elements through the several figures,FIG. 1is a flowchart of a first method for an auto-voltage detect charger. The method100begins with a battery charger applying a predetermined test charge to a battery engaged by the charger102. The magnitude of the predetermined test charge may be between 1 amp and 10 amps, such as a 2 amp test charge. The duration of the predetermined test charge can be between 0.5 seconds and 10 seconds. In one embodiment, the test charge is applied for a short period of time, such as 1 or 2 seconds, in order to stabilize the battery status and to prepare the battery for charging and analysis.

During one or more steps of the method100, one or more characteristics of a battery may be monitored. For example, the battery charger may monitor the voltage and the temperature of the battery.

Various batteries may be used according to systems and methods of the present invention. The battery may comprise a 6 volt (V), 12 volt, or 24 volt battery. Or, the battery may be rated at other voltages, e.g. a 48 volt or 72 volt battery. The battery may comprise a lead acid battery, sealed acid battery, gel battery, or an absorbed glass mat (AGM) battery. In other embodiments, the battery may comprise another type of battery.

After the battery charger applies a predetermined test charge to the battery102, a microprocessor in communication with the battery charger determines a condition of the battery based at least in part on a response to the predetermined test charge104. The response may comprise an initial terminal voltage, or a battery temperature, and may be measured immediately after the test charge is applied to the battery.

The condition of the battery may be charged, ready for charging, or fault/error. The microprocessor may determine the condition of the battery by comparing the initial terminal voltage of the battery against one or more voltage values, or levels. In some scenarios, the microprocessor may determine the condition of the battery based at least in part on whether the initial terminal voltage lies above, below, or within a certain range of voltage values.

If the initial terminal voltage of the battery after the test charge is above or below certain voltage levels, or thresholds, then the microprocessor may determine that the condition of the battery is fault or error. For example, if the initial terminal voltage lies below a low voltage threshold, such as 1.5V, then the microprocessor may determine that the battery is malfunctioning, broken, and/or not correctly inserted into the battery charger. Or, if the initial terminal voltage lies above a high voltage threshold, such as 28V, then the microprocessor may also determine that the battery is malfunctioning, broken, and/or not correctly inserted.

The voltage thresholds may be predetermined based on the expected voltage ratings of the batteries to be tested. For example, if the battery charger is expected to charge batteries having voltage ratings of 6V, 12V, and 24V, then the low voltage threshold may be set at some value below 6V, such as at 1.5V, and the high voltage threshold may be set at some value above 24V, such as 28V. In another example, if 24V and 48V batteries are expected to be tested, then the low voltage threshold may be set below 24V (i.e. 20V), and the high voltage threshold may be set above 48V (i.e. 54V). It may be expected that a battery having any voltage above or below such thresholds is malfunctioning, and should not be used.

After the condition of the battery has been determined, an indication of the condition may be generated. If the battery condition is ready to be charged, then a steady green light may be activated. Or, if the battery condition is fault/error, a red light may be activated. Battery condition indicators may be audible, visual, or tactile. Examples of such indications include warning beeps, blinking lights, or vibration. Alternatively, the battery charger may generate no indication at all, but simply begin the charging process, or turn off.

In some embodiments, the microprocessor may accurately determine both the condition of a battery along with the battery's voltage rating immediately following the test charge phase102-104, without having to initiate the precharge process106(described below). In one embodiment, a test charge102is applied to a battery, and the initial terminal voltage is greater than 16V but less than 28V. Based on this initial terminal voltage range, the microprocessor determines that the condition of the battery is charged. Additionally, the microprocessor determines that the voltage rating of the charged battery is 24V, i.e., a voltage rating corresponding to a battery voltage rating within the voltage range of 16V to 28V.

In other embodiments, the battery charger may only be able to determine a condition of the battery based on the battery's response to the test charge. For example, an initial terminal voltage after the test charge phase is measured between 1.5V and 16V. Based on this initial terminal voltage, the microprocessor determines that the condition of the battery is ready for charging, but cannot accurately determine the voltage rating of the battery.

A battery in fault or error condition may be improperly connected to the device, or in one alternative, broken. The condition of the battery may be based at least in part on the voltage of the battery. The condition of the battery may also be based on other characteristics of the battery, such as the battery temperature.

After the microprocessor determines the condition of the battery, the microprocessor initiates a precharge process, illustrated inFIG. 1as steps106-112. During the precharge process, the battery charge applies a small precharge current to the battery, waits, applies a small precharge current to the battery again, and waits again. As shown inFIG. 1, the precharge process begins with the battery charger applying a first predetermined precharge current to the battery for a predetermined period of time106. The precharge current may comprise a 2 A current. The predetermined period of time may be 30 seconds, 45 seconds, 60 seconds, or 120 seconds. The preferred pre-charge is a 2 amp constant current charge for 120 seconds.

After applying a precharge current106, the battery charger waits for a second predetermined period of time108. During the wait period, the battery charger applies no current (or a negligible current) to the battery. The second predetermined period of time may be the same amount of time as the first period of time, or may be a different period of time. For example, the second predetermined period of time may be 30 seconds, 45 seconds, 60 seconds, or some other time period. The preferred stop or wait period is 30 seconds.

As shown in steps110-112, the precharge cycle is repeated. After the first wait step108, the battery charger then applies a second predetermined precharge current to the battery for a third predetermined period of time110. In some embodiments, the second predetermined precharge current is the same magnitude as the first predetermined precharge current. In other embodiments, the second predetermined precharge current is a different magnitude than the first predetermined precharge current.

The battery charger then waits for a fourth predetermined period of time112. During the wait period, the battery charger applies no current (or a negligible current) to the battery. The fourth predetermined period of time may be the same amount of time as the other predetermined periods of time, or may be a different period of time. In one embodiment, the first, second, third, and fourth predetermined periods of time are all 60 seconds. As shown inFIG. 1, the precharge phase comprises two cycles, each cycle comprising a precharge current period and a wait period. In other methods according to the present invention, the precharge phase may comprise three or more cycles of a precharge current and a wait period.

Finally, after the test charge phase102-104and the precharge phase106-112, the microprocessor determines a voltage rating of the battery based at least in part on the condition of the battery and a response to the precharge process114. The response to the precharge process may comprise a measurement of the terminal voltage of the battery after the precharge process. The voltage rating of the battery may be determined, at least in part by comparing the terminal voltage of the battery after the precharge process against one or more voltage thresholds, or levels. In some scenarios, the microprocessor may determine the voltage rating of the battery based at least in part on whether the terminal voltage of the battery after the precharge process lies above, below, or within a certain range of voltage values.

In some cases, a battery may not respond (i.e. may not charge) to the precharge process106-112. For example, if the terminal voltage of the battery after the precharge process lies below a certain voltage level, or threshold, then the microprocessor may not be able to determine that the voltage rating of the battery. Instead, the microprocessor may determine that the condition of the battery is fault or error—that is, that the battery is malfunctioning, broken, and/or not correctly inserted into the battery charger.

In one embodiment, a microprocessor causes a 2 A test charge to be applied to a battery for a duration of 1 second. After the 2 A test charge is applied to the battery, the initial terminal voltage of the battery is measured at 9V. In the embodiment, the 9V battery voltage lies between the low voltage threshold of 1.5V and the high voltage threshold of 28V. Accordingly, the microprocessor determines that the battery condition is ready to be charged.

Next, the microprocessor initiates the precharge phase, which consists of two precharge cycles. The precharge phase beings with the microprocessor causing a first predetermined precharge current of 2 A to be applied to the battery for 60 seconds. After the first precharge current, no charge (i.e. 0 A) is applied to the battery for 60 seconds. The precharge cycle is repeated, and a second predetermined precharge current of 2 A is applied to the battery for 60 seconds. The last step of the precharge process in the example comprises waiting another 60 seconds.

In the embodiment, the final terminal voltage of the battery is measured at 11.5V after the precharge process. The microprocessor compares the final terminal voltage to a plurality of voltage ranges corresponding to different batteries. First, the microprocessor determines that the battery was successfully charged because the final terminal voltage is greater than the minimum voltage threshold 1.5V. Next, the microprocessor determines that the battery is not a 6V battery, because it has a voltage greater than 9V. Finally, the microprocessor determines that the voltage rating of the battery is 12V, since the final terminal battery voltage is in the range of 9V to 18V. In this manner, the voltage rating of a battery is determined automatically without user input, even when the terminal battery voltage (e.g. 11.5V) does not exactly match a standard voltage rating (e.g. 12V).

FIG. 2is a flowchart of a second method for an auto-voltage detect charger. As shown inFIG. 2, the method200comprises two phases: a test charge phase206-218and a precharge phase220-252. A condition of the battery is determined after the test charge phase, and a voltage rating of the battery is determined after the precharge phase.

The method200begins by powering on the system202. After power on202, a microprocessor control unit (MCU) in communication with a battery charger enters an initialization state, i.e. setup204. During setup204, the MCU clears and initializes memory, time values, and the state of each input/output (I/O) port. During setup204, the MCU may begin to monitor one or more characteristics of a battery, such as the terminal voltage, current, and/or temperature of the battery. The MCU may monitor one or more characteristics of a battery during some or all of method200.

After setup204, the test charge phase206begins. As shown inFIG. 2, a test charge phase of the auto-voltage detect process comprises steps206-218. During the test charge phase, a short initial charge is applied to the battery. The short, initial charge may be configured to provide an initial charge to the battery in order to determine whether a battery is ready to be charged or cannot be charged (i.e. is malfunctioning). The test charge phase begins by applying a predetermined test charge Itc to the battery206. The predetermined test charge Itc may comprise a small, short charge, such as a 2 A charge applied for a duration of 1 second.

After the test charge is applied to the battery, the MCU measures the initial terminal voltage of the battery Vi, and compares the initial terminal voltage Vi to a plurality of voltage levels, or thresholds. As shown inFIG. 2, the MCU first compares the initial terminal voltage Vi with a first predetermined threshold, the maximum voltage threshold Vmax208. The maximum voltage threshold of the battery Vmax may be based on the expected voltage range of the battery being tested. For example, if the voltage range of the battery is expected to be between 6V and 24V, the maximum voltage threshold Vmax may be set to 28V. Or, if the voltage range of the battery is expected to be between 24V and 48V, the maximum voltage threshold Vmax may be set to 54V.

If the initial terminal voltage Vi exceeds the maximum voltage threshold Vmax, then the battery may be malfunctioning, or in an error condition. In one example, the maximum voltage threshold Vmax is set at 28V. If the battery responds to the initial test charge206with an initial terminal voltage Vi above 28V, then the MCU may determine that the battery is malfunctioning, or there is an error210. In the example, the error state210reflects that the battery may not be charged by the charger due to an improper voltage.

If the initial terminal voltage Vi does not exceed the maximum voltage threshold Vmax208, then the MCU may compare the initial terminal voltage Vi with a precharge threshold Vpc212. If the initial terminal voltage Vi exceeds the precharge threshold Vpc, then the condition and the voltage rating of the battery may be immediately determined214. For example, if an initial terminal voltage Vi measured at 25V exceeds a precharge threshold Vpc of 20V, but does not exceed a maximum voltage threshold Vmax of 28V, then the MCU may determine that the battery is charged, and rated at 24V. By setting the voltage range between the precharge threshold Vpc and the maximum voltage threshold Vmax to encompass one battery voltage rating, the charged batteries having a voltage rating in the corresponding voltage range may be quickly and accurately determined.

If the initial terminal voltage Vi does not exceed the first predetermined threshold Vmax208, and does not exceed the precharge threshold Vpc212, then the battery charger compares the initial terminal voltage Vi with a third predetermined threshold, a minimum voltage threshold Vmin216. If the initial terminal voltage Vi is below the minimum voltage threshold, then the MCU may determine that the battery is malfunctioning, or there is an error218. The error condition218may indicate that the battery is broken, incorrectly installed, or has been removed from the auto-voltage detector. In some scenarios, the minimum voltage threshold Vmin is set to 1.5V. If the initial terminal voltage Vi is below 1.5V after the test charge206, then the MCU determines that the battery condition is faulty/error218.

If the battery is ready to be charged (i.e. not fully charged and not malfunctioning), then the precharge phase220begins. The MCU may determine that the battery is in a condition ready to be charged if the initial terminal voltage Vi of the battery lies between the minimum voltage threshold Vmin and the maximum voltage threshold Vmax. The precharge phase may consist of one or more cycles, each cycle comprising the steps of applying a predetermined precharge current to the battery, and a wait step.

The precharge phase220begins by applying a predetermined precharge current Ipc to for a first predetermined period of time T1to the battery. In some embodiments, the predetermined precharge current Ipc has the same magnitude as the predetermined test charge Itc206. In other embodiments, the predetermined precharge current Ipc has a different magnitude than the predetermined test charge Itc. Typically, the predetermined precharge current Ipc is applied to the battery for a much longer duration during the precharge phase220than the predetermined test charge Itc is applied to the battery during the test charge phase. In one embodiment, the predetermined precharge current is 2 amps, and is applied to the battery for a duration of 60 seconds. During the first predetermined period of time T1, the microprocessor continues to cause the precharge current to be applied until the predetermined period of time T1is over 222.

The MCU may monitor one or more characteristics of the battery during the precharge phase220. For example, the MCU may monitor the terminal voltage Vbt, current I, and the temperature of the battery. As shown in method200, the voltage of the battery may be continually compared to the minimum voltage threshold Vmin224during the precharge phase. If the terminal battery voltage Vbt falls below the minimum voltage threshold Vmin, then the MCU may determine that the battery is malfunctioning, or there is an error226. Error state226may indicate that the battery is broken, not properly installed, or has been removed from the auto-voltage detector.

If the current of the battery I stays above a predetermined current threshold Imin, i.e. a minimum current threshold228, then the microprocessor will continue to cause the precharge current to be applied220. If the current of the battery I falls below the minimum current threshold Imin, then the microprocessor may compare the terminal voltage of the battery Vbt against the minimum voltage threshold Vmin230. If the current of the battery I falls below the minimum current threshold Imin228and the terminal voltage battery falls below the minimum voltage threshold Vmax, then the microprocessor may determine that the battery condition is faulty/error232.

During the second step of the precharge cycle, the MCU causes the battery charger to wait for a predetermined wait time234. In one embodiment, the predetermined wait time, i.e. the second predetermined period of time T2, is 30 seconds. In other embodiments, the wait time is some other duration, such as 45 seconds, 60 seconds, or 75 seconds. The wait step234continues236for the duration of the wait time.

After the second predetermined period of time T2is over, i.e. the wait period has been completed, then the microprocessor checks to see if the precharge cycle has occurred twice, or only once238. If the precharge cycle has only occurred once, then the precharge cycle will repeat220. Otherwise, the MCU may measure the final terminal voltage of the battery Vf. In some embodiments, the precharge cycle may occur three or more times, rather than just two.

After the precharge phase220is completed, then the MCU measures the final terminal voltage Vf of the battery, and compares the final terminal voltage Vf against one or more voltage ranges intended to discover the voltage rating of the battery. As shown inFIG. 2, the MCU may first compare the final terminal voltage Vf to the minimum voltage threshold Vmin240. If the final terminal voltage Vf lies below the minimum voltage threshold Vmin, then the MCU may determine that the battery is malfunctioning, or there is an error242. Error condition242may indicate that the battery is broken, incorrectly installed, or has been removed from the auto-voltage detector.

If the final terminal voltage Vf exceeds the minimum voltage threshold Vmin, then the MCU compares the final terminal voltage Vf against a first predetermined voltage threshold V11244. If the final terminal voltage Vf lies between the minimum voltage threshold Vmin and the first predetermined voltage threshold V11, then the microprocessor may determine the voltage rating of the battery corresponds to a battery with a voltage that would lie in the range between Vmin and V11246.

If the final terminal voltage Vf exceeds the minimum voltage threshold Vmin and the predetermined voltage threshold V11, then the microprocessor compares the final terminal voltage Vf against a second predetermined voltage threshold V12248. If the final terminal voltage Vf lies between the first predetermined voltage threshold Vmin and the second predetermined voltage threshold V12, then the microprocessor may determine the voltage rating of the battery corresponds to a battery with a voltage that would lie in the range between V11and V12250If the final terminal voltage Vf exceeds the second predetermined threshold V12, then the microprocessor may determine that the voltage rating of the battery corresponds to a battery with a voltage that would lie in the range between V12and Vmax252.

FIG. 3is a flowchart of a third method for an auto-voltage detect charger. The method300may begin302after the voltage rating of a battery is determined by a microprocessor (MCU) of an auto-voltage detect system. In step304, the terminal voltage of a battery Vbt is compared to a predetermined voltage threshold V1. The predetermined voltage threshold V1may be set to determine whether a battery is ready to be charged, or whether the battery needs to run through the precharge phase306. V1may be predetermined based at least in part on the voltage rating of the battery to be charged, which may be automatically determined through method200. In one embodiment, V1is set to 5V for a 6V battery rating. In other embodiments, V1may be set to 10V for a 12V battery rating, or V1may be set to 20V for a 24V battery rating.

If the terminal voltage of the battery Vbt does not exceed the predetermined voltage threshold V1, then the battery charging may be suspended, and the battery may enter the precharge phase306. The precharge phase306can help to stabilize the battery status and prepare the battery for charging and analysis.

If the terminal voltage of the battery Vbt exceeds the predetermined voltage threshold V1, then the MCU sets one or more battery charging parameters308. The one or more battery charging parameters may be determined based at least in part on charging settings310received from manual input. Charging settings can include a battery type (i.e. battery chemistry) and/or a battery charging rate. For example, the battery type, or chemistry, may be lead acid, gel, or absorbed glass mat (AGM). The charging rate may be low, medium, or high. The charging settings may be specified310through a keypad input, or through other manual input methods, such as buttons, toggles, and/or switches.

After the MCU determines or sets the charging parameters308, the battery charger enters constant current charging mode312. Constant current charging mode312may comprise a “bull charging mode.” During constant current charging mode, various characteristics of the battery are monitored314, such as the temperature of the battery and the voltage of the battery.

Once the voltage of the battery arrives at a predetermined level the charging mode will switch from constant current charging312to constant voltage charging316. The charging voltage of the constant voltage charging mode316may be predetermined based on the type of battery. For example, the charging voltage may be set to 14.4V for a flood battery, 14.0V for a gel battery, and 14.6V for an AGM battery.

During constant voltage charging316, the current of the battery Ia may be monitored318. If the battery current drops below the full current setting320, the battery may go into a float charge mode322. The float charge mode322may represent the fact that the battery is fully charged. The float charge mode322may comprise a battery maintenance mode.

FIG. 4is a block diagram of a system for auto-voltage detect charger. As shown inFIG. 4, the system400comprises AC input power402, auxiliary power404, pulse width modulation (PWM) control406, microprocessor control unit (MCU)408, manual input410, monitor412, and battery414.

Power from the AC input power402may be transformed via a high frequency voltage transformer.

MCU408may comprise a device capable of executing computer-executable program instructions. Such microprocessors may include one or more microprocessors, ASICs, and state machines. Such processors may further comprise programmable electronic devices such as PLCs, programmable interrupt controllers (PICs), programmable logic devices (PLDs), programmable read-only memories (PROMs), electronically programmable read-only memories (EPROMs or EEPROMs), or other similar devices. Such processors include, or can be in communication with, media which stores instructions that when executed by the processor, cause the processor to perform the steps described herein. Embodiments of computer-readable media include, but are not limited to, an electronic, optical, magnetic, or other storage or transmission device capable of providing a processor with computer-readable instructions. Other examples of suitable media include, but are not limited to, a floppy disk, CD-ROM, DVD, magnetic disk, memory chip, ROM, RAM, an ASIC, a configured processor, all optical media, all magnetic tape or other magnetic media, or any other medium from which a computer processor can read instructions. Also, various other forms of computer-readable media can transmit or carry instructions to a computer, including a router, private or public network, or other transmission device or channel, both wired and wireless. The instructions can comprise code from any suitable computer-programming language, including, for example, C, C+, C++, Visual Basic®, Java™, Python™, and JavaScript®.

The MCU408may comprise a single chip microprocessor configured to control operation of the charger. The MCU408may comprise two timers, and two groups of input/output (I/O) ports. Additionally, the MCU408may include an 8-bit analog to digital (A/D) converter and a 7-bit digital-to-analog (D/A) converter. By having a pair of timers, ports, and converters, the MCU408may be more economical and efficient than other MCUs.

The MCU408can be configured to control output voltage through PWM control406. PWM control406may utilize high-frequency switch power technology. The MCU408may receive various charging parameters through manual input410. In some embodiments, manual input410comprises a keypad. The keypad may be configured to input parameters such as the charging speed (e.g. slow, medium, or fast) or type of battery (e.g. gel, lead-acid, or gel).

The monitor412can be configured to monitor various characteristics of the battery414before, during, and after voltage detection and/or charging. The monitor412may measure or monitor battery characteristics such as the terminal voltage of the battery414, the current produced by the battery414, and the temperature of the battery414.

FIG. 5is a block diagram of a system for auto-voltage detect charger. The system500illustrated inFIG. 5shows one embodiment of a hardware design functional block diagram. The system500adopts high-frequency switch power technique and converts alternating current (AC) to direct current (DC). The main power circuit is controlled by a first microprocessor U1, which provides the battery charging power. Another PWM circuitry is controlled by a second microprocessor U2, which functions to provide auxiliary power to control the Integrated Circuits, MCU, and ventilation fan.

The product adopts high-frequency switch power technique and converts AC input502to DC. The system500comprises two PWM control circuitries530,532. The main power circuit and the first PWM control530is controlled by a first microprocessor MCU528, which provides the battery charging power.

A second microprocessor is configured to control the second PWM control532. The second PWM control can be configured to provide the auxiliary power (+5V DC, +40V DC) to control integrated circuits, a microprocessor, and/or a ventilation fan.

FIG. 6is a circuit diagram of a system for auto-voltage detect charger. The system600can be configured to automatically control some or all of the operation of the auto-voltage detect charger. In some embodiments, various charging characteristics may be specified. As one example, different charging rates, such as low, medium and high, may be selected. As another example, the type of battery, such as gel, lead acid, or AGM, may be selected in order to adopt the best charging characteristic.

The system600may be configured to monitor the battery status (i.e. configured to monitor various characteristics of the battery), such as the battery voltage, battery current, and/or battery temperature. The system600may monitor characteristics of the battery in real time, and report the condition and/or characteristics of the battery on a display. By continuously monitoring one or more characteristics of the battery, the system600may also control for various charging errors, such as short circuit, overload, overheat, reverse connection, etc.

The system600may also be configured to control charging of the battery through different charging stages according to the condition and/or measured characteristics of the battery. The different charging stages may include an initiation stage, a bulk charge (constant current) stage, a top off (constant voltage) stage, and a float charge stage. The different charging stages facilitate quick and efficient battery charging.

FIG. 7is a first aspect of the circuit diagram ofFIG. 6. The system700illustrated inFIG. 7comprises AC input702, fuse704, input N, thermal resistor708, and transient voltage suppression diode710. AC voltage702is provided through fuse704. Input706is connected with thermal resistor708and in parallel with transient voltage suppression diode710to AC input702. Thermal resistor708can be configured to provide protection to the circuit. Under a ‘cold condition,’ thermal resistor708can be configured to reduce the power of a startup surge current. Under an overvoltage condition, transient voltage suppression diode710will become shorted or fuse704will blow in order to protect the secondary circuitry.

The system700further includes capacitor712, capacitor714, transformer716, capacitor718, capacitor720, and transformer722. Capacitor712and Capacitor714comprise a differential mode noise filter. Capacitor712, transformer716, capacitor714, capacitor718, capacitor720, and transformer722form a low pass filter configured to filter out high frequency noise from the power line. Capacitor720, Capacitor722, Transformer716, Transformer722, an additional transformer (not shown inFIG. 7), and two additional capacitors (not shown inFIG. 7) comprise a common mode noise filter, which is configured to suppress the common mode noise.

Additionally, as shown inFIG. 7, bridge type rectifier724can be configured to convert the AC voltage to full wave DC voltage. Polarized capacitor726can be configured to filter and smooth the wave shape DC voltage into a flat DC supply and provide the flat DC supply to connected circuitry.

FIG. 8is a second aspect of the circuit diagram ofFIG. 6. As shown inFIG. 8, the system800comprises a microprocessor unit (MCU)802. The MCU802comprises 8 input pins: pin1“com”, pin2“in-”, pin3“cs”, pin4“rc”, pin5“gnd”, pin6“out”, pin7“vcc” and pin8“ref.” The MCU802begins operation when input pin7vcc, receives power from a diode.

Resistor804and Capacitor806form a resistor-capacitor oscillator (RC oscillator) with a 67 kHz frequency for MCU802oscillator circuitry. Pin6out of MCU802outputs a pulse width modulation signal to transistor828. Transistor828forms the switching network through the coil rectifier830of transformer830.

Transformer830comprises four coil rectifiers832,834,836, and838. Coil rectifiers834,836of transformer830will generate power with the switching AC network in coil rectifier832. Coil rectifier836will then provide the regulated, stable voltage supply Vcc to MCU802through transistor824, which no longer requires the Aux. supply from MCU1002(shown inFIG. 10).

The output voltage is compared to Vref and the result is feedback to MCU802pin1through920and transistor840. MCU802will generate the PWM signal from pin6and control transistor828on/off timing for the proper voltage regulate purpose. Current sensing signal will pass through922, which in turn controls920and provides feedback to pin1of MCU802, which controls828on/off timing to establish a proper output level to keep the current required.

Resistor808, resistor810, capacitor812, capacitor814, and resistor816form a current detect circuitry, which protects the charger from overload condition. The system may also avoid peak surges through transformer820.

FIG. 9is a third aspect of the circuit diagram ofFIG. 6. As shown inFIG. 9, the system900comprises amplifier902and Light Emitting Diode (LED)920. A current sensing signal will pass through amplifier902, which in turn controls LED920and feedback to pin1of MCU802. MCU802can then control on/off timing to establish a proper output level to maintain the required current.

Coil rectifier834will provide the main power supply to filter network diode910, diode912, inductor914and capacitor916, which then provides the DC supply to charger on/off control transistor1104(shown inFIG. 11). 902will get the output voltage sampling through resistor network904,906and variable resistor908.

FIG. 10is a fifth circuit diagram of an aspect of a system for auto-voltage detect charger. The system1000shown inFIG. 10comprises a microprocessor1002, inductor1004, capacitor1006, coil rectifier1008, diode1010, transistor1012and transistor1014. Voltage is supplied through coil rectifier1008through diode1010to provide a clean and regulate +5V power supply for microprocessor1002.

Resistor1016, resistor1018, resistor1020, resistor1022, and diode1024form the voltage sample and feedback the output status to microprocessor1002through diode1024and transistor1026. Then microprocessor1002will generate the PWM pulse signal to control the output voltage forming a feedback loop. Coil rectifier1028supplies the regulated DC bias voltage to1104for on/off control.

Upon AC power up, rectifier voltage output fed to pin8of microprocessor1002, which starts the switching operation. Inductor1004provides switching voltage through capacitor1006for a regulated voltage Vcc to pin5of microprocessor1102. As shown inFIG. 8, the regulated 12V is also fed to the MCU802for Vcc supply. The regulated 12 v is provided to the MCU802via pin7through diode806and resistor804.

The system1000also comprises reverse protection circuitry for the charger. Transistor1014can detect a reverse connection and turn on transistor1012, which then provides an active high signal to a microprocessor through BR. In response, the microprocessor will not turn on output. Additionally, the microprocessor may generate an alarm signal by activating a buzzer.

FIG. 11is a sixth circuit diagram of an aspect of a system for auto-voltage detect charger. As shown in system1100, a battery1102is engaged by the battery charger. Charging control1104switches battery charging on and off. The microprocessor1110regulates charging control1104through transistor1108and transistor1106. When1104is turned on, the main power circuit can deliver power to the battery1102and start or continue the charging process.

FIG. 12is a seventh circuit diagram of an aspect of a system for auto-voltage detect charger. As shown inFIG. 12, the system1200comprises a first voltage reference1202and a second voltage reference1204. The voltage references1202,1204(i.e. Vref) can provide a reference voltage for a sampling voltage comparison. In some embodiments, the voltage reference for charging a battery should vary according to the voltage rating of the battery. For example, while a 6V, 12V or 24V battery is charged, the selected voltage reference varies according to the voltage rating of the battery. A microprocessor (not shown inFIG. 12) may select the appropriate voltage reference after the battery voltage is detected. As shown inFIG. 12, the microprocessor may select the appropriate voltage reference from voltage reference1202or voltage1204, and turn off the opposite transistor1208or1206.

Transistor1206and transistor1208can provide a voltage shunt (i.e. Vsc) in parallel to the sample voltage and conduct the needed voltage reference Vref. The appropriate voltage reference can work in the voltage feedback control to the PWM control circuitry. The microprocessor will generate the necessary constant voltage (i.e. CV) signal and select the reference voltage to achieve the constant voltage control.

FIG. 13is an eighth circuit diagram of an aspect of a system for auto-voltage detect charger. As shown inFIG. 13, the system1300comprises a microprocessor1302. The microprocessor1302is in communication with a first temperature sensor1304and a second temperature sensor1306. In other embodiments, the system1300may comprise zero, one, three, or more temperature sensors.

The first temperature sensor1304may comprise an environmental temperature sensor. An environmental temperature sensor can be configured to convert the temperature to a voltage signal. The microprocessor1302may receive the voltage signal based on the and compensate the voltage deviation on battery according to different temperature measurements.

The second temperature sensor1306may be configured to detect overheating inside the battery charger. The microprocessor1302may receive signals from the second temperature sensor1306and control operation of the charger. In some embodiments, the microprocessor1302may control a fan based on signals received from the second temperature sensor1306. Or, the microprocessor1302may stop the charging process.

In one scenario, the battery charger may overheat due to an abnormal condition, such as battery failure, or a charger malfunction. The first temperature sensor1304and/or the second temperature sensor1306may detect an abnormal temperature, and communicate with the microprocessor1302. The microprocessor1302then transmits a fan control signal to reduce the internal temperature, or alternative, shuts down the battery charger.

FIG. 14is a ninth circuit diagram of an aspect of a system for auto-voltage detect charger. The system1400illustrated inFIG. 14comprises a first microprocessor1402and a second microprocessor1404. In the embodiment shown inFIG. 14, the second microprocessor1404forms the control center of the charger.

Each microprocessor1402,1404comprises a plurality of input pins. The second microprocessor1404comprises a pin configured to receive input from one or more manual input devices, such as a keypad, button, toggle, or switch. The system1400comprises a first switch1406, a second switch1408, and a third switch1410in communication with the second microprocessor1404. Each switch1406,1408, and1410may comprise a manual input. Switch1406may comprise a manual input for battery type. Switch1408may comprise a manual input for charge rate. Switch1410may comprise a start/stop or on/off manual input. In other embodiments, other parameters for voltage detection and/or charging may be manually specified.

The second microprocessor1404may also comprise one or more input/output control signals. The various control signals may control for 12/24 volts, a reference voltage, fan control, output, reverse connection, constant voltage mode, constant current mode, voltage sampling, current sensing, and buzzer control.

The second microprocessor1404can be configured to be in communication with a display (not shown inFIG. 14). In some embodiments, the second microprocessor1404may comprise a display control. The display control may receive information based on the charger or battery status, and generate a visual indication shown on the display. For example, the second microprocessor1404may monitor the terminal voltage of the battery, and generate a visual indication representing a fully charged battery to be shown on the display.

Systems and methods for an auto-voltage detect charger may have various advantages over conventional methods for battery charging. Embodiments of the auto-voltage detect charger may be configured to automatically detect the voltage of batteries with various voltages, for example, ranging from 6V batteries to 72V batteries. In addition, embodiments of the auto-voltage detect charger may quickly and efficiently charge batteries to their full capacity.

As described above, the invention device is an automatic charge control with linear transformer battery charger. As described below, the preferred embodiment is shown and described with reference toFIGS. 15-19. The preferred embodiment uses an 8 bit controller to regulate the turn on angle for SCR (Silicon Control Rectifier), in such case to control the output voltage and current. With the intelligent software and hardware design, the charger can automatically detect voltage range for most car batteries type and other batteries, which do not need users to select the voltage and avoid mis-operation of selection that cause failure of charging process.

With reference toFIG. 15, the charger automatically controls most of the operation, monitor the battery status and charge with different stage according to the condition. With the real time monitor, reporting different status and condition on panel display. Different charging rate of low, medium and high is selectable with different battery capacity. Also offer the choice for different batteries type like Gel, Standard lead acid, AGM to adopt the best charging characteristic. In the preferred embodiment ofFIGS. 15-19, the battery voltage detection system follows the following general procedure:1. Apply a first precharge with a 2 amp constant current for approximately 120 seconds, then stop the charge for approximately 30 seconds.2. Apply a second precharge with a 2 amps constant current for approximately 120 seconds, then stop the charge for approximately 30 seconds.3. Apply a third precharge with a 2 amp constant current for approximately 120 seconds, then stop the charge for approximately 30 seconds.4. Actively discharge for approximately 30 second (i.e., resistor discharge), then check for a faulty battery (e.g., open cell so the battery voltage drops fast).5. Apply a fourth precharge with a 2 amp constant current for approximately 120 seconds, then stop the charge for approximately 30 seconds.6. Begin battery detection and predict battery voltage type/level.

Different charging stage for initiation, bulk charge (constant current), tap off (constant voltage) and float charge can guarantee that the battery is in the best state of charging. The invention of automatic recognition of battery voltage type (6V/12V/24V) can further reduce the manual operation and ease of operation.

FIG. 16is the MCU firmware functional block. The core processing unit controls the battery charging current/voltage according to different information received from different units. The CPU also sent out control result and charger status to the display unit and feedback to user operation.

With reference to the software design flowchart for battery voltage recognition ofFIG. 17, the charger differentiates batteries for 6V, 12V and 24V automatically and does not need manual selection. The principle of the invention adopts intermittence charging. In the beginning of charging charge up battery with small startup current, then stop charge for battery stabilize, and recharge the battery for battery terminal voltage detection. With the monitoring of battery terminal voltage Vbt, the rising speed of battery voltage can provide information of the battery type.

Upon startup, the MCU enters the initialization state. Clear and setup memory, initial timer value, set up the corresponding state of each I/O port. The system monitors input keypad and starts detection of current, voltage and temperature sensor.

According to the voltage detect value Vbt, the charger predict:

Vbt>28V: Error mode

3.0V>Vbt: Error mode or no battery

The charger will go into a 2 A precharge stage for 120 seconds, then stop for 60 seconds. The battery will settle down will this start up charge current, then the charger will re-start the 2 A charging process for other cycles. According to the preferred embodiment, there are a total of 3 cycles.

After the charge up stage, the invention will proceed for the next stage of fail battery detect as illustrated inFIG. 17, whereby:

Or a drop of >1V for Vbt (indicates an error mode means for dead cell battery or dead battery.)

The system then proceeds for another 120 second charge and 60 second stop cycle.

Then, the system will start the battery voltage Vbt detection for prediction, whereby:

With the succession of battery voltage detection, the charger will go into the formal charging process.

After the finish of voltage detection stage, the charger will setup the parameter for a proper charging process and start the charging as illustrated by the charging process flowchart ofFIG. 18. V1is the parameter to determine whether the battery needs to have a pre-charge stage, whereby:

If Vbt<V1, a 2 A pre-charge mode is processed which can help to maintain the battery and extend the battery life.

Upon completion of the pre-charge mode, the charger will setup different parameters according to user settings for battery types and charging rates.

The charger will enter bull charge mode which is constant current charging. During the charging, temperature and status is monitor and will dynamic adjusting the charging characteristic.

With voltage arrive the pre-set level; charging will go into the tap off mode under a constant voltage condition.

The foregoing detailed description of the certain exemplary embodiments of the invention has been provided for the purpose of explaining the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. This description is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification and the scope of the appended claims. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. Modifications and equivalents will be apparent to practitioners skilled in this art and are encompassed within the spirit and scope of the appended claims and their appropriate equivalents. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative which might be predictable to a person having ordinary skill in the art.

Only those claims which use the words “means for” are to be interpreted under 35 USC 112, sixth paragraph. Moreover, no limitations from the specification are to be read into any claims, unless those limitations are expressly included in the claims.