GB2103896A - Battery charger - Google Patents

Battery charger Download PDF

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Publication number
GB2103896A
GB2103896A GB08215858A GB8215858A GB2103896A GB 2103896 A GB2103896 A GB 2103896A GB 08215858 A GB08215858 A GB 08215858A GB 8215858 A GB8215858 A GB 8215858A GB 2103896 A GB2103896 A GB 2103896A
Authority
GB
United Kingdom
Prior art keywords
battery
output
voltage
charge
charging
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08215858A
Inventor
Anthony Edward Perei
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Perei Auto Devices Ltd L E
Original Assignee
Perei Auto Devices Ltd L E
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Perei Auto Devices Ltd L E filed Critical Perei Auto Devices Ltd L E
Priority to GB08215858A priority Critical patent/GB2103896A/en
Publication of GB2103896A publication Critical patent/GB2103896A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007Regulation of charging or discharging current or voltage
    • H02J7/00712Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage

Abstract

A battery is charged via a thyristor TH1 which is turned on when a sensor Ic1 detects that the voltage across the charger output is less than the post charge off-load voltage of the battery, and is off when the voltage across the output is above the on charge open unit full charge battery voltage. A precision voltage regulator is used to form the sensor Ic1 and compares the voltage across the output with an internal reference. Resistor R6 and R7 are connected to provide the hysteresis between the ON/OFF threshold level, levels of about 12.2 volts and 13.7 volts being used when charging a 12 volt lead- acid battery. LED 2 is energised at a low level to indicate battery charging, at an intermediate level to indicate an open or short circuit at the output, and at a high level to indicate a reverse- connected battery. <IMAGE>

Description

SPECIFICATION Improvements in electrical storage battery charging circuits This invention relates to a charging circuit arrangement for electrical storage batteries, especially lead-acid batteries used in vehicles, boats or caravans.
An object of this invention is to provide a charger circuit and a charger unit incorporating the circuit which may remain permanently connected to the battery, the unit switching charging current on or off automatically according to the state of charge of the battery.
According to this invention there is provided a charging means for a battery comprising an input for connection to a D.C. battery charging power source, an output for connection to a battery to be charged, switching means serially connected between input and output and operative through a control potential to electrically connect or disconnect the output from the input, sensing means connected across the output operative to supply a potential to the switching means to connect same when the output voltage is less than the post charge off-load value and to disconnect same when the output voltage is above the on charge open circuit full charge value.
The charging circuit preferably is combined with a mains transformer and rectifier forming the D.C. power source. The switching means may conveniently be a triode thyristor fed with a control potential at the gate electrode.
The sensing means may comprise a comparator, one input being connected with the output and the other input connected with a reference potential.
The arrangement according to the invention is primarily useful for charging 12 volt lead-acid batteries such as those used in vehicles, boats or aircraft an when operative may supply a charging current of some 6 amps. The sensing circuit is operative to connect the switching means when the sensed battery voltage is below about 12.20 volts, and to disconnect the switching means when the sensed voltage is above about 13.70 volts.
When the battery is fully charged, the unit is automatically switched off. Should the battery volts drop for any reason the charger will automatically cut in again and recycle. This enables the user to leave the charger connected to the battery for an indefinite period with no adverse effect on the battery and is suited for uses where the battery is left unattended for long periods.
The arrangement is an advantage of known charging circuits which reduce the charge current, actively or passively as the on charge battery voltage increases. Such systems always produce a trickle charge current which is unacceptable when the charger is left connected for several weeks.
An embodiment according to the invention is described with reference to the accompanying drawing showing a circuit diagram of an example and illustrating further and preferred features in the construction.
Although automatic battery chargers are known in the commercial field, the domestic market continues to use a simple transformer rectifier arrangement. This invention seeks to introduce a modest form of control which will alleviate battery abuse caused by repeated or prolonged overcharging. The automatic charger described is for lead acid cells and uses the post charge inflection voltage characteristic to initiate termination of charge.
Referring to the drawing, the circuit elements for automatic control comprise a precision voltage regulator IC1 forming a sensing means and a reverse blocking triode thyristor TH 1 forming a switching means. The voltage regulator is connected to form a bi-stable trigger circuit with thresholds corresponding to the battery post charge and open circuit potentials.
The battery terminal voltage is applied via D5 and R6 to the potential divider R2, P1 and R3, with the resultant voltage between the wiper of P1 and the negative terminal of the battery applied to the inverting input of the differential comparator 1C1. An internal voltage reference from 6 is applied via R5 to the non-inverting input of the comparator.
Diode D5 is provided to avoid damage to the control circuit in the event of reverse battery connection. Resistor R6 operates in conjunction with the current limiting resistor R7, to provide a predetermined hysteresis corresponding to the ON/OFF threshold levels. Capacitor C1 has the dual role of ripple voltage attenuation and assured "start up".
Resistor R5 approximately matches the effective resistance of the potential divider R2, P 1 and R3, to optimise the temperature stability.
Capacitors C2 and C3 are included to prevent parasitic oscillations. Transistor Q1 operates as a ievel shifter to obviate reverse potentials on the output pin 3 of lC1 . ThyristorTHl is 1 is the main control switch element.
Status indication is provided by light emitting diodes. LED1 is illuminated when the mains voltage is applied to the transformer TX primary, provided that there is continuity through the thermal cutout CO. LED2 provides three levels of illumination; low level indicates that the battery is charging (confirmed by the ammeter A), brighter indicates that the charger output terminals are either open or short circuit, and brightest indicates that the battery is reverse connected.
Diodes D1 to D4 form a bridge rectifier circuit supplying the charging current.
Claims
1. A charging means for a battery comprising an input for connection to a D.C. battery charging power source, an output for connection to a battery to be charged, switching means serially connected between input and output and operative through a control potential to electrically connect or disconnect the output from
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in electrical storage battery charging circuits This invention relates to a charging circuit arrangement for electrical storage batteries, especially lead-acid batteries used in vehicles, boats or caravans. An object of this invention is to provide a charger circuit and a charger unit incorporating the circuit which may remain permanently connected to the battery, the unit switching charging current on or off automatically according to the state of charge of the battery. According to this invention there is provided a charging means for a battery comprising an input for connection to a D.C. battery charging power source, an output for connection to a battery to be charged, switching means serially connected between input and output and operative through a control potential to electrically connect or disconnect the output from the input, sensing means connected across the output operative to supply a potential to the switching means to connect same when the output voltage is less than the post charge off-load value and to disconnect same when the output voltage is above the on charge open circuit full charge value. The charging circuit preferably is combined with a mains transformer and rectifier forming the D.C. power source. The switching means may conveniently be a triode thyristor fed with a control potential at the gate electrode. The sensing means may comprise a comparator, one input being connected with the output and the other input connected with a reference potential. The arrangement according to the invention is primarily useful for charging 12 volt lead-acid batteries such as those used in vehicles, boats or aircraft an when operative may supply a charging current of some 6 amps. The sensing circuit is operative to connect the switching means when the sensed battery voltage is below about 12.20 volts, and to disconnect the switching means when the sensed voltage is above about 13.70 volts. When the battery is fully charged, the unit is automatically switched off. Should the battery volts drop for any reason the charger will automatically cut in again and recycle. This enables the user to leave the charger connected to the battery for an indefinite period with no adverse effect on the battery and is suited for uses where the battery is left unattended for long periods. The arrangement is an advantage of known charging circuits which reduce the charge current, actively or passively as the on charge battery voltage increases. Such systems always produce a trickle charge current which is unacceptable when the charger is left connected for several weeks. An embodiment according to the invention is described with reference to the accompanying drawing showing a circuit diagram of an example and illustrating further and preferred features in the construction. Although automatic battery chargers are known in the commercial field, the domestic market continues to use a simple transformer rectifier arrangement. This invention seeks to introduce a modest form of control which will alleviate battery abuse caused by repeated or prolonged overcharging. The automatic charger described is for lead acid cells and uses the post charge inflection voltage characteristic to initiate termination of charge. Referring to the drawing, the circuit elements for automatic control comprise a precision voltage regulator IC1 forming a sensing means and a reverse blocking triode thyristor TH 1 forming a switching means. The voltage regulator is connected to form a bi-stable trigger circuit with thresholds corresponding to the battery post charge and open circuit potentials. The battery terminal voltage is applied via D5 and R6 to the potential divider R2, P1 and R3, with the resultant voltage between the wiper of P1 and the negative terminal of the battery applied to the inverting input of the differential comparator 1C1. An internal voltage reference from 6 is applied via R5 to the non-inverting input of the comparator. Diode D5 is provided to avoid damage to the control circuit in the event of reverse battery connection. Resistor R6 operates in conjunction with the current limiting resistor R7, to provide a predetermined hysteresis corresponding to the ON/OFF threshold levels. Capacitor C1 has the dual role of ripple voltage attenuation and assured "start up". Resistor R5 approximately matches the effective resistance of the potential divider R2, P 1 and R3, to optimise the temperature stability. Capacitors C2 and C3 are included to prevent parasitic oscillations. Transistor Q1 operates as a ievel shifter to obviate reverse potentials on the output pin 3 of lC1 . ThyristorTHl is 1 is the main control switch element. Status indication is provided by light emitting diodes. LED1 is illuminated when the mains voltage is applied to the transformer TX primary, provided that there is continuity through the thermal cutout CO. LED2 provides three levels of illumination; low level indicates that the battery is charging (confirmed by the ammeter A), brighter indicates that the charger output terminals are either open or short circuit, and brightest indicates that the battery is reverse connected. Diodes D1 to D4 form a bridge rectifier circuit supplying the charging current. Claims
1. A charging means for a battery comprising an input for connection to a D.C. battery charging power source, an output for connection to a battery to be charged, switching means serially connected between input and output and operative through a control potential to electrically connect or disconnect the output from the input, sensing means connected across the output operative to supply a potential to the switching means to connect same when the output voltage is less than the post charge offload value and to disconnect same when the output voltage is above the on charge open circuit full charge value.
2. Means in accordance with Ciaim 1, combined with a mains transformer and a rectifier forming the D.C. power source.
3. Means in accordance with Claim 1 or 2, wherein the switching means is a triode thyristor fed with a control potential at the gate electrode.
4. Means in accordance with any preceding claim, wherein the sensing means is a comparator, one input being connected with the output and the other input connected with a reference potential.
5. Means for regulating the charging current to a battery broadly as described herein and embodying a circuit substantiaily as shown in the drawing.
GB08215858A 1981-06-05 1982-06-01 Battery charger Withdrawn GB2103896A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08215858A GB2103896A (en) 1981-06-05 1982-06-01 Battery charger

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8117325 1981-06-05
GB08215858A GB2103896A (en) 1981-06-05 1982-06-01 Battery charger

Publications (1)

Publication Number Publication Date
GB2103896A true GB2103896A (en) 1983-02-23

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB08215858A Withdrawn GB2103896A (en) 1981-06-05 1982-06-01 Battery charger

Country Status (1)

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GB (1) GB2103896A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5043650A (en) * 1988-02-26 1991-08-27 Black & Decker Inc. Battery charger
EP2608342A1 (en) * 2011-12-20 2013-06-26 Kohler Co. Overvoltage Protection System and Method
CN104779669A (en) * 2015-04-13 2015-07-15 深圳市格瑞普电池有限公司 Lithium ion battery pack provided with charging protection circuit

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5043650A (en) * 1988-02-26 1991-08-27 Black & Decker Inc. Battery charger
EP2608342A1 (en) * 2011-12-20 2013-06-26 Kohler Co. Overvoltage Protection System and Method
US9425608B2 (en) 2011-12-20 2016-08-23 Kohler Co. Overvoltage protection system and method
CN104779669A (en) * 2015-04-13 2015-07-15 深圳市格瑞普电池有限公司 Lithium ion battery pack provided with charging protection circuit

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