CA2024656A1 - Method and apparatus for charging a battery in high amp and automatic charging modes - Google Patents
Method and apparatus for charging a battery in high amp and automatic charging modesInfo
- Publication number
- CA2024656A1 CA2024656A1 CA002024656A CA2024656A CA2024656A1 CA 2024656 A1 CA2024656 A1 CA 2024656A1 CA 002024656 A CA002024656 A CA 002024656A CA 2024656 A CA2024656 A CA 2024656A CA 2024656 A1 CA2024656 A1 CA 2024656A1
- Authority
- CA
- Canada
- Prior art keywords
- battery
- predetermined threshold
- current
- threshold voltage
- rate
- 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.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
- H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J2207/20—Charging or discharging characterised by the power electronics converter
Abstract
ABSTRACT OF THE DISCLOSURE
A battery charger adapted to be electrically connected to the terminals of a battery for providing a charge to the battery, the battery charger comprising a device for supplying charging current to the battery, the current supplying device being operable to alternatively and selectively supply current at a first and second rate, the first rate providing for high rate charging of the battery, circuitry for sensing the voltage of the battery while the charger is connected to the battery, the sensing circuitry being adapted to be coupled to the battery, circuitry for alternatively selecting the first rate and the second rate, the selecting circuitry being coupled to the supplying circuitry and to the severing circuitry, circuitry for severing the supply of charging current to the battery when the second rate is selected, and when the sensing circuitry senses battery voltage in excess of a first predetermined threshold voltage, and for resuming the supply of current to the battery at the second rate when the sensing circuitry senses battery voltage below a second predetermined threshold voltage lower than the first predetermined threshold voltage, the severing circuitry being coupled to the current supplying device and to the sensing circuitry.
A battery charger adapted to be electrically connected to the terminals of a battery for providing a charge to the battery, the battery charger comprising a device for supplying charging current to the battery, the current supplying device being operable to alternatively and selectively supply current at a first and second rate, the first rate providing for high rate charging of the battery, circuitry for sensing the voltage of the battery while the charger is connected to the battery, the sensing circuitry being adapted to be coupled to the battery, circuitry for alternatively selecting the first rate and the second rate, the selecting circuitry being coupled to the supplying circuitry and to the severing circuitry, circuitry for severing the supply of charging current to the battery when the second rate is selected, and when the sensing circuitry senses battery voltage in excess of a first predetermined threshold voltage, and for resuming the supply of current to the battery at the second rate when the sensing circuitry senses battery voltage below a second predetermined threshold voltage lower than the first predetermined threshold voltage, the severing circuitry being coupled to the current supplying device and to the sensing circuitry.
Description
2~2~
Ml-:T~lOD AND APPARATUS FOR C~ARGING A BATTERY IN
IIIGH AMP AND AUTOM~TIC ClkARGING MODES
FIELD OF THE INVENTION
_ This invention relates to battery chargers and more particularly to automotive battery chargers and the like including means for sensing the state of charge of a battery and interruptLng the charging cycle when the battery has been fully charged.
BACKGROUND OF THE INVENTION
Some battery chargers used in applications such as in charging automotive batteries and the like include means fox supplying a high charging current to the battery, for example, 40 amps to provide for rapid charging of the battery. They may include means for reducing the charge being supplied to the battery once the voltage of the battery has reached a predetermined voltage. For example, in a conventional 12 volt au~omatic battery charger, the c~arge is reduced to 0.1 amps or less once the voltage of the battery reaches approximately 14.4 volts. The reduced charge of 0.1 amps or less is then continuously supplied to the battery to maintain the charge on the battery. In operation of these battery chargers, if the battery charger continues to supply a low current charge to the battery for extended periods of time, the water in the battery will be converted to hydrogen and oxygen which is dissipated 6 ~ ~
from the ba~tery causing damage to the battery. In addition, if the battery charger continues to supply a low current charqe r to the battery for extended periods of time, the grids of the hattery being charged will corrode at an accelerated pace, thereby causing the battery to ail prematurely. On the other hand, if the battery is left uncharged for a long period of time, self discharge of the battery will cause the active material of the battery to sulfate, thus also causing irreversible damage to the battery.
Some battery chargers of the type including means for sensing the state of charge of a battery and interrupting the charging cycle when the battery has been fully charged further include means for continuing to monitor the state of charge of the battery and for automatically restarting the supply of charging current to the battery when the battery's state of charge is below full charge.
Another type of battery charger supplies only relatively small charges to a battery, for example a charge at the rate of 10 amps, and includes means for sensing the charge of the battery and means for shutting off the charging current to the battery once the voltage of the battery reaches a predetermined voltage, for example 14.4 volts. The battery charger will then continue to sense the charge of the battery and if that voltage falls below a predetermined voltage, the charger will once again supply a charging current to the battery until the voltage of the battery is raised to 14.4 volts, and is again interrupted.
In other battery chargers, means are provided for supplyinq a charge to the battery at a relatively high rate of charge, such as at approximately 40 amps, or alternatively at a 2~2~6~
lower rate s~lch as at 10 to 15 amps. These battery chargers commonly include a switch or control permitting the operator to select the operating mode of the battery charger such that it operates at either a high current rate or at a lower current of approximately 10 to 15 amps.
Other bat~ery chargers have included means for charging the battery at a high rate of charge and alternative means for charging the battery at a lower rate, and further including means for timing the selected rate of charqe. In these chargers the battery is then charged at the selected rate of charge until the timer turns off the charger.
_MMARY OF THE INVENTION
The present invention provides an improved battery charger including means for alternatively supplying current to a battery at a relatively high rate of charge, i.e. at a high current, to provide for rapid charging of the battery, and at a lower rate of charge, i.e. at a lower current, the charger including means for sensing the relative charge of the battery and means for switching off or severing the current to the battery whenever the battery is being charged at the second rate and the sensed charge of the battery exceeds a first predetermined threshold voltage. The means for sensing also continues to monitor or sense the charge on the battery and causes a charging current to be supplied to the battery in the event that the charge of the battery falls below a second predetermined threshold voltage, i.e. slightly below a full state of charge.
In another aspect of the invention, a timer means is i6 provided for causing the means for chargirlg at the high rate of charge to operate for a predeterm.ined time period, and for thereafter causing the means fox charging at the lower rate (automatic current on/off) to opera~e.
In another aspect of the invention, means are provided for adjllsting the firs-t predetermined thre~shold voltage (at which threshold the current to the battery is switched off), the adjusting means comprising a continuously variable selector.
In another aspect of the invention, means are provided for adjusting the second predetermi.ned threshold voltage ~a~
which threshold the current to the battery is switched on).
The means for adjusting the second predetermined threshold voltage comprises a continuously variable selector in one aspect of the invention.
In another aspect of the invention, the battery :
charger includes first; second, and third discrete visual ::
indicators, means for illuminating the fi.rst indicator in -response to the battery charger being connected to a so~lrce of alternating current, means for illuminating the second indicator while the current supplying means supplies charging current to the battery at the second current rate, and means for illuminating the third indicator in response to the severing means severing the supply of charging current to the battery while the second (i.e. automatic) charging xate has been selected. The third indicator, when illuminated by the third mentioned illuminating means, thereby provides a visual indication that the second charging rate (i.e. automatic mode has ~een selected, and that the current supplying means will resume th~ supply of charging current to the battery when the sensing means senses battery voltage below the second ~2~
predeterlnined voltage~
In ano~her aspect of the inventi.on, t:he current supplying means compr.ises a transformer having a pr.imary winding adapted to be electrically connected t:o a source of alt:ernati~g cllrrent, and a secondary winding adapted to be electrically connected to the battery, and the severing means includes relay contacts operative to open to interrupt curxent flow through the primary winding of the transformer to sever the supply of charglng current to the battery when the sensing means senses battery voltage in excess of the upper predetermined threshold voltage.
One aspect of the invention provides a method of charging a bat-tery comprising the steps of providing means for supplying charging current to the battery, the current supplying means being operable to alternatively supply current at a first rate and at a second rate, selecting one of the .
first rate and the second rate, electronically severing the supply at charging current to the battery when the second rate is selected and when the battery voltage exceeds a first predetermined threshold voltage, and electronically resumlng the supply of current to the battery at the second rate when .
the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
Another aspect of the invention provides a method of charging a battery comprising khe steps of providing means for supplying chargi.ng current to the battery, the current supplying means being operable to selec-tively supply current at a first rate of at least 30 amps and at a second rate, selecting the first rate for a selected period of time and -`` 2~2~
.. . .
~hereafter selecting the second rate, electronically severing the supp1y of charging current to the battery when the second rate is selected and when the battery voltage exceeds a first predetermined threshold voltaqe, and electronically resuming the supply of current to the battery at the second rate when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
A further aspect of the invention provides a method of . . .
charging a battery comprising the steps of providing means for supplying at least 14 amps of charging current to the battery, electronically severing the supply of charging cùrrent to the battery when the bat-tery voltage exceeds a first predetermined -~
threshold voltage, and electronically resuming the supply of current to the battery when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
These and other features and advantages of the invention will become apparent to those of ordinary s~ill in the art upon review of the following detailed description of the preferred embodiment of the invention, which is given by way of example, reference being made to the appended drawings.
BRIEF DESCRIPTION OF THE
VIEWS OF THE DRAWINGS
Fig. l shows a circuit schematic of a battery charger embodying a first embodiment of the invention.
Fig. 2 shows a circuit schematic of an alternate embodiment of the invention.
Before these embod;ments of the invention are e~plained in detail, it is to be understood that the invention is not limited in its application to the details of construction, arrangement of components, and component values set forth in the following description or illustrated in the drawings. The invention is capable of o-ther em~odiments and of being practiced and carried out in various ways. Also, it i5 to be understood that the phraseology and terminology employed herein is for the purposa of description and should not be regarded as limiting.
DE~AILED DESCRIP~ION OF THE PREFERRED
EMBODIMENT OF THE INVENTION
Shown in Fig. 1 is a circuit schematic of a battery charger 10 embodying the invention. The charger 10 of the illustrated e~bodiment is adapted to be used with a standard twelve volt automotive battery 12 having a positive terminal 12A and a negative terminal 12B.
The battery charger l0 includes means for sensing the vol~age of the battery 12 when the battery 12 is electrically connected to the charger 10. In the preferred embodiment, the sensing means comprises a first and second voltage comparator IClA and Icls. The comparator IClA is used to determine if the sensed battery voltage is in excess of a first predetermined threshold voltage, and the comparator IClB is used to determine if the sensed battery voltage is below a second predetermined threshold voltage. Although the comparators IClA and IClB of the illustrated embodiment are part of a dual comparator package, discret~ comparator packages could be used.
.
:
2 ~
The battery charger 10 further includes a voltage divider compr.isinc3 resistors R13 and R14. The voltage across the battery 12 ~i.e. across the positive and negative terminals l~A and l2s, respective1y, of the battery) is applied, via a fuse F1 (included in the charger 10), to the voltage divider comprisinq R13 and R14. The charger 10 further includes an electrolytic capacitor C1 in parallel connection with the resistor R14, the parallel combination of R14 and Cl being connected between R13 and the negative terminal 12B of the batt:ery 12. The voltage that appears across the capacitor Cl, using the illustrated component values, is 41~ of the battery voltage and is applied to the non~inverting input, pin 3, of compara~or IClA, through a resistor R7 ~that i9 included in the charger 10). The voltage that appears across the capacitor Cl is also applied directly to the non-inverting input, pin 5, of the comparator IClB. The positive supply terminal, pin 8, of the co~parators IClA and IClB i~ connected to a positive supply voltage, which is preferably a regulated voltage. The n0gative supply terminal, pin 4, of the comparators IClA and IClB i5 connected to ground, in the illustrated embodiment. The output, pin 7, of the comparator IClB is connected to the non-inverting input, pin 3, of the comparator IClA via a s~itching diode D3 included in tha charger 10. More particularly, the anode of the diode D3 is connected to the non-inverting input, pin 3, of the comparator IClA, and the cathode of the diode D3 is connected to the output, pin 7, of the comparator IClB.
qhe battery charger 10 further includes a diode D1 having an anode connected to the output, pin 1, of the comparator IClA. The charger 10 further includes a resistor R2 connected be~ween the cathode of the diode Dl and the non-inverting input pin 3, of the comparator IClA.
The sensing means ~urther includes means for adjusting the first threshold voltage, the adjus~ing means comprising a continuously variable selector. In the illustratecl embodiment, the means for adjusting the first threshold voltage comprises a potentiometer P2 variable at the inverting input, pin 2, of comparator IClA and having one end connected to a reference voltage via a resistor R9, and another end connected to ground via a resistor R1, the resistors R1 and RS being included in the sensing means. Preferably, -the irst reference voltage is a regulated voltage, and when the illustrated component values are used, is regulated to be 6.8 volts.
The sensing means further comprises means for adjusting the second predetermined threshold voltage. More particularly, the means for adjusting the second predetermined threshold voltage comprises a continuously variable selector.
~ore particula~ly, the means for adjusting the second predetermined threshold voltaqe comprises a potentiometer P1 variable at the inverting input, pin 6, of the comparator IC1 and having one end connected to a second reference voltage via a resistor R16, and another end connected to ground via a resistor R15, the resistors R16 and R15 being included in the sensing means. Preferably, the second reference ~oltage is a regulated voltage, and, in the illustrated embodiment, the second reference voltage is the same as the first reference voltage.
Thus, the first and second predetermined threshold voltages, ~hich are used to determine ~hen the charger 10 should stop and start charging, as will be outlined below, can ~2~
be adjusted in view of battery type or temperature (a battery vol~age that represen~s a fully charged battery at one '!
~emperature does not necessarily represent a fully charged battery at another temper~ture). In one embodiment of the invention, the potentiometers Pl and P2 are acces.sible to the user of the charger 10. In another embodiment, P1 and P2 are adjustable by the manufacturer of the charger 10 (for use of the charger 10 with a specific type of battery, for example)~
Using the illustrated component values, the first predetermined . . .
threshold is ~djustable between 13.6 ~nd 16.2 VDC, and the second predetermined threshold is adjustable between 13.6 and i2.1 VDC.
The battery charger 10 further includes means for regulating voltage so that the first and second predetermined threshold voltages do not change. The illustrated voltage regulating means includes voltage regulator IC2, which provides ~8 volts (DC) in the illustrated embodiment, connected to the battery, and a zener diode D4 that is fed by the voltage regulator IC2, through a resistor R17 that is also included in the regulating means. In the illustrated embodiment, the diode D4 is a 6.8 volt zener diode. The 8 volts set by the voltage regulator IC2 supplies the comparators XClA and IClB at pin 8, while the 6.8 volts set by the zener diode D4 is used as the first and second reference voltage with the potentiometers Pl and P2. The first and second predetermined threshold voltages are thus kept stable over a range of variations of loads on the charger 10 and temperatures.
The voltage regulating means further includes a silicon rectifying blocking diode D2 supplying current to the voltage regulator IC2 from the positive terminal 12A of the ba~tery 12 via the fuse Fl. The diode D2 prevents the charger 10 from a~tempting to char~e the battery 12 if the battery is connec~ed back~ards and the battery voltage polarity is reversed. The voltage regulating means further includes a capacltor C2 connected between one end of the resistor R17 and ground, and a capacitor C3 connected between the other end of -the resistor R17 and ground, the capacitor C3 being provided to filter out potential electrical noises.
The battery charger 10 includes means for supplying charging current to the battery, the current supplying means being operab.le to alternatively 5upply current at a first and second rate, the first rate providing for high rate charying of the battery, i.e., at least 30, and preferably 40, charging amps - charging amps being defined as amps supplied to the battery while the battery is being charged as opposed to being boosted, and the second rate being at least 14, and preferably 15, charging amps.
In the illustrated embodiment, the current supplying means comprises a transformer X1,~ such as transformer having a primary winding XlA having a first end XlAA, a second end XlAC, and a tap XlA8 between the first end XlAA and the second end XlAC, and adapted to be electrically connected to household alternating current (e.g. 120 VAC), and a secondary winding XlB
adapted to be electrically connected to the hattery 12. In the illustrated embodiment, the ratio of the number of turns between the tap XlAB and the second end XlAC to the number of turns of the portion of the secondary winding XlB that can ~:
supply cu~rent to the battery 12 at any one time ~i.e. between the centertap of the secondary winding XlB and the anode of one of the diodes D6 or D7) is 7.88:1, and the ratio of the number .
, of turns of the entire primary winding XlA to t:he portion of the secondary wi.nding XlB that can supply current to the battery 12 at any one time (i.e. between the centertap of the secondary winding XlB and the anode of one of the diodes D6 or D7) is 9.41:1. The charger 10 includes diodes D6 and D7 having anodes respectively connected to opposite ends of the secondary winding XlB. The diodes D6 and D7 have cathodes that are adapted to be connected to the positive terminal 12A of the battery 12 to supply positive current to the positive terminal 12A. The secondary winding XlB includes a centertap collnected to the negative terminal 12B of the battery to supply negative current to the negative terminal 12B. The charger 10 optionally, but preferably, further includes an ammeter A
connected to the secondary winding XlB for series connection with the battery 12.
More particularly, in the .illustrated embodiment, when the first charging rate i.s selected, only the portion of the primary winding X1A between the tap XlAB and the end XlAC of the primary wincling XlA is energiæed with 120 volts of alternating current. When the second charging rate is selected, the entire primary winding XlA, between the ends XlAA
and XlAC, is selectively energiæed with 120 volts of alternating currentO
The charger 10 further includes means for severing (i.e., æero current, no trickle current) the supply of charging current from the transformer Xl to the battery 12 when the second charging rate is selected and when the sensing means senses battery voltage and for resuming the supply of current to the battery at the second charging rate when the severing means senses battery voltage below the second predetermined , 2~2~5~
threshold volta~e.
Al~hough one skilled in the art will readily realize that alternative embodiments are possible, the sensing means and the severing means of the illustrated embodiment are used exclusively when the second chargin~ rate has been selected.
In the illustrated embodiment, the severing means includes a relay K1 having contacts 23 and 22 operative to open to sever current flo~ through the primary winding of the transformer to sever the supply of charging current -to the battery when the sensing means senses battery voltage in excess of the first predetermined threshold voltage. In the illustrated embodiment, the relay!K1 is rated for 10 amps through and 120 volts AC across the contacts 20 and 22. The relay Kl further includes a coil 24. Application of 12 vol~s across the coi.l ~4 results in the clo~ing of the contacts 20 and 22. ~he contacts 20 and 22 open when the coil 24 is not energized (i.e. when no voltage is applied across the coil 24). The coil 24 has a first end 26 connected to the cathode of diode D2, and a second end 28. The contact 20 is connected to the end XlAA of the primary winding XlA.
The severing means further includes a correct transistor Ql having an emitter connected to the voltage regulating means. More particularly, the emitter of -the transistor Ql is connected to the ~8 volts output of the regulating means. The transistor Ql also has a base connected to the output, pin 1, of the comparator IClA, via resistor R4.
The severing means further includes a resistor R5 connected between the emltter and the base of the transistor Q1, as well as a resistor ~3 connected between the emitter of the transistor Ql and the output pin 1, of the comparator IClA.
The sev~ing means further includes a npn transistor Q2 having an emitter connected to ground, a collector, and a base. The severing means ~urther includes a resistor R11 connected between the base and the emitter of the transistor Q2j and a resistor ~10 connected between the c:ollector of transistor Ql and the base of transistor Q2. The severing means further includes a resistor R12 connected between the collector of the transistor Q2 and the end 28 of the coil 24.
The severing means further includes a diode DS having a anocle connected to the end 28 of the coil 24, and a cathode connected to the end 26 of the coil 24.
In operation, when the voltage of the battery 12 is less than or equal to the threshold voltage set by the potentiometer P1, then the output, pin 7, of IClB is pulled down to zero volts. This pulls the non-inverting input, pin 3, of the comparator IClA low through the switching diode D3, and causes the voltage at the output, pin 1, of the comparator IClA
to be pulled down to zero volts. This turns on the pnp transistor Q1 which turns on the npn transistor Q2, thereby resulting in the coil 24 of the relay Kl being energized. When the battery becomes charged, the output, pin 7 of the comparator IClB will go to +8 VDC, causing the switching diode D3 to be back-biased. This causes the voltage at the non-inverting input, pin 3, of the comparator IClA to be governed by the voltage across the electrolytic capacitor Cl through the input resistor R7. When the voltage of the battery 12 reaches the threshold voltage set by the potentiometer P2, the output, pin 1 of the comparator IClA will become +8 VDC.
This turns off the transistors Ql and Q2r de-energizing the relay Xl and thus disconnecting the 120 VAC source from the ~2~ 6 primary XlA of ~he transEormer X1 of the charger. The sensing means, regulatinq ~eans, and severing means are powered by the battery 12 when the charger lO is off (i.e. 120 VAC is not applied to the primary of the charying transf~rmer), and are powered by the charger when the charger is on.
The battery charger 10 urther includes means for alternatively selecting the first charging rate and the second charging rate.
The battery charger 10 includes lines 50 and 52 adapted to be connected -to a hot and a neutral line, respectively, of the source of household 12~ volt alternating current. In the preferred embodiment, the lines 50 and 52 terminate in a 3-pronged connector for connection to the hot and neutral lines. The 3-pronged connector preferably has a ground pin connected in a conventional fashion to a cabinet (not shown) housing the battery charger 10. The line 50 is connected to an end XlAC of the transformer primary winding XlA.
The means for selecting the first charging rate and the second charging rate comprises a switch SW manually movable (by the user of the battery charger) between a position 62 thigh or fask charge mode~ and a position 64 (automatic mode) to connect the lead 52 to the tap XlAB or to the contact 22, respectively. When the switch SW is moved to the position 62, 120 volts of alternating current is provided to the transformer primary between the tap XlAB and the end XlAC. When the switch SW is ~oved to the position 64, 120 volts of alternating current is provided to the transformer primary between the ends XlAA and XlAC, when khe con-tacts 20 and 22 are closed.
Thus, means are provided for alternatively selecting the first charging rate and thP second charging rate.
20~5~
-16~
Ir~ ~he preferred embodiment, the switch SW is further manually movable to an "off" position 60 to disconnect the lead 52 from the transformer primary XlA.
The batte~y charger lO further includes first, second, and third discrete visual indlcators, means for illuminating the irst indicator in response to the battery charger ~eing connected to the source of alternating current, means for illuminating the second indicator while the supplying means supplies charging current to the battery at the second current rate, and means for illuminating the third indicator in response to the severing means severing the supply of charging cur~ent to the battery while the second (i.e. automatic) charging rate has been selected. The third indicator, when illuminated by the third mentioned illuminating means, thereby provides a visual indication that the second charging rate (i.e. automatic mode~ has been selected, and that the current supplying means will resume the supply of charging current to the battery when the sensing means senses battery voltage below the second predetermined ~oltage. More particularly, in the illustrated embodiment, the first visual indicator is a red neon light, NEl, connected in the battery charger 10 between the leads 50 and 52, the second visual indicator is an amber neon light NE2, connected across the primary winding XlA of the transformer Xl, between the ends XlAA and XlAC, and the third visual indicator is a green neon light NE3 having one end connected to the contact 20 and another end connected to the contact 22. Thus, by way of electrical connections in the battery charger 10, means are provided for llluminating the fixst indicator in response to the battery charger being connected to the source of alternating current, for illumillating ~he second indicator while the supplying means sopplies charging current to the ba-ttery at the second current rate, and for illuminating the third indicator in response to the severing means severing the supply of charcling current to the battery while the second li.e. automatic~ charging xate has been selected. The third indicator, when illuminated by the third mentioned illuminating means, thereby provides the visual indication that the second charging rate (i.e. autornatic mode) has been selected, and that the current supplying means will resume the supply of charginq current to the battery when the sensing means senses battery voltage below the second predetermined voltage. The red, amber, and green neon indicators are preferably arranged vertically or horizontally in traffic light order.
The battery charger lO of the preferred embodiment of the invention includes a fan 70 connected between the tap XlAB
of the transformer primary and the lead 50, and operative to cool the battery charger lO ~hen the means for selectively and alternatively connecting the first and second charging means to the battery l2 connects the first charging means to the battery 12.
Shown in Fig. 2 i9 an alternative embodiment of the invention, a portion of which is identical to the embodiment shown in Fig. l, like reference numerals indicating like componen~s~ which portion will not again be described in detail.
In the alternative embodiment of the in~ention sho~n in Fig. 2, the means for alternatively selecting the first charging rate and the second charqing rate comprises timer means, including a timer motor, for selectinq the first rate for a selected period of time and for selecting the second rate 2 ~
after the selectecl period of time expires. More particularly, in the illllstrated embodiment, the timer means comprises a timer Tl operati.ve to connect the lead 52 to the tap XlAB (fast charge mode) for a per~od of time selected by the user of the battery charger 10, and to thereafter connect the lead S2 to the contact 22 (automatic mode). The timer T1 can also be operated by the user of the battery charger 10 to connect the second charging means to the battery without the first current supplying means first being connected to the battery 12. An appropriate timer Tl is an electromechanical timer such as Model CX 43706 by Ma].lory Timers, Valparaiso, Indiana; or Model MS 65 by Corpono and Pons (divisiorl of Eaton Controls Products), 76530 Grand-Couronne, France.
Various of the features of the invention are set forth in the following clai~s.
Ml-:T~lOD AND APPARATUS FOR C~ARGING A BATTERY IN
IIIGH AMP AND AUTOM~TIC ClkARGING MODES
FIELD OF THE INVENTION
_ This invention relates to battery chargers and more particularly to automotive battery chargers and the like including means for sensing the state of charge of a battery and interruptLng the charging cycle when the battery has been fully charged.
BACKGROUND OF THE INVENTION
Some battery chargers used in applications such as in charging automotive batteries and the like include means fox supplying a high charging current to the battery, for example, 40 amps to provide for rapid charging of the battery. They may include means for reducing the charge being supplied to the battery once the voltage of the battery has reached a predetermined voltage. For example, in a conventional 12 volt au~omatic battery charger, the c~arge is reduced to 0.1 amps or less once the voltage of the battery reaches approximately 14.4 volts. The reduced charge of 0.1 amps or less is then continuously supplied to the battery to maintain the charge on the battery. In operation of these battery chargers, if the battery charger continues to supply a low current charge to the battery for extended periods of time, the water in the battery will be converted to hydrogen and oxygen which is dissipated 6 ~ ~
from the ba~tery causing damage to the battery. In addition, if the battery charger continues to supply a low current charqe r to the battery for extended periods of time, the grids of the hattery being charged will corrode at an accelerated pace, thereby causing the battery to ail prematurely. On the other hand, if the battery is left uncharged for a long period of time, self discharge of the battery will cause the active material of the battery to sulfate, thus also causing irreversible damage to the battery.
Some battery chargers of the type including means for sensing the state of charge of a battery and interrupting the charging cycle when the battery has been fully charged further include means for continuing to monitor the state of charge of the battery and for automatically restarting the supply of charging current to the battery when the battery's state of charge is below full charge.
Another type of battery charger supplies only relatively small charges to a battery, for example a charge at the rate of 10 amps, and includes means for sensing the charge of the battery and means for shutting off the charging current to the battery once the voltage of the battery reaches a predetermined voltage, for example 14.4 volts. The battery charger will then continue to sense the charge of the battery and if that voltage falls below a predetermined voltage, the charger will once again supply a charging current to the battery until the voltage of the battery is raised to 14.4 volts, and is again interrupted.
In other battery chargers, means are provided for supplyinq a charge to the battery at a relatively high rate of charge, such as at approximately 40 amps, or alternatively at a 2~2~6~
lower rate s~lch as at 10 to 15 amps. These battery chargers commonly include a switch or control permitting the operator to select the operating mode of the battery charger such that it operates at either a high current rate or at a lower current of approximately 10 to 15 amps.
Other bat~ery chargers have included means for charging the battery at a high rate of charge and alternative means for charging the battery at a lower rate, and further including means for timing the selected rate of charqe. In these chargers the battery is then charged at the selected rate of charge until the timer turns off the charger.
_MMARY OF THE INVENTION
The present invention provides an improved battery charger including means for alternatively supplying current to a battery at a relatively high rate of charge, i.e. at a high current, to provide for rapid charging of the battery, and at a lower rate of charge, i.e. at a lower current, the charger including means for sensing the relative charge of the battery and means for switching off or severing the current to the battery whenever the battery is being charged at the second rate and the sensed charge of the battery exceeds a first predetermined threshold voltage. The means for sensing also continues to monitor or sense the charge on the battery and causes a charging current to be supplied to the battery in the event that the charge of the battery falls below a second predetermined threshold voltage, i.e. slightly below a full state of charge.
In another aspect of the invention, a timer means is i6 provided for causing the means for chargirlg at the high rate of charge to operate for a predeterm.ined time period, and for thereafter causing the means fox charging at the lower rate (automatic current on/off) to opera~e.
In another aspect of the invention, means are provided for adjllsting the firs-t predetermined thre~shold voltage (at which threshold the current to the battery is switched off), the adjusting means comprising a continuously variable selector.
In another aspect of the invention, means are provided for adjusting the second predetermi.ned threshold voltage ~a~
which threshold the current to the battery is switched on).
The means for adjusting the second predetermined threshold voltage comprises a continuously variable selector in one aspect of the invention.
In another aspect of the invention, the battery :
charger includes first; second, and third discrete visual ::
indicators, means for illuminating the fi.rst indicator in -response to the battery charger being connected to a so~lrce of alternating current, means for illuminating the second indicator while the current supplying means supplies charging current to the battery at the second current rate, and means for illuminating the third indicator in response to the severing means severing the supply of charging current to the battery while the second (i.e. automatic) charging xate has been selected. The third indicator, when illuminated by the third mentioned illuminating means, thereby provides a visual indication that the second charging rate (i.e. automatic mode has ~een selected, and that the current supplying means will resume th~ supply of charging current to the battery when the sensing means senses battery voltage below the second ~2~
predeterlnined voltage~
In ano~her aspect of the inventi.on, t:he current supplying means compr.ises a transformer having a pr.imary winding adapted to be electrically connected t:o a source of alt:ernati~g cllrrent, and a secondary winding adapted to be electrically connected to the battery, and the severing means includes relay contacts operative to open to interrupt curxent flow through the primary winding of the transformer to sever the supply of charglng current to the battery when the sensing means senses battery voltage in excess of the upper predetermined threshold voltage.
One aspect of the invention provides a method of charging a bat-tery comprising the steps of providing means for supplying charging current to the battery, the current supplying means being operable to alternatively supply current at a first rate and at a second rate, selecting one of the .
first rate and the second rate, electronically severing the supply at charging current to the battery when the second rate is selected and when the battery voltage exceeds a first predetermined threshold voltage, and electronically resumlng the supply of current to the battery at the second rate when .
the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
Another aspect of the invention provides a method of charging a battery comprising khe steps of providing means for supplying chargi.ng current to the battery, the current supplying means being operable to selec-tively supply current at a first rate of at least 30 amps and at a second rate, selecting the first rate for a selected period of time and -`` 2~2~
.. . .
~hereafter selecting the second rate, electronically severing the supp1y of charging current to the battery when the second rate is selected and when the battery voltage exceeds a first predetermined threshold voltaqe, and electronically resuming the supply of current to the battery at the second rate when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
A further aspect of the invention provides a method of . . .
charging a battery comprising the steps of providing means for supplying at least 14 amps of charging current to the battery, electronically severing the supply of charging cùrrent to the battery when the bat-tery voltage exceeds a first predetermined -~
threshold voltage, and electronically resuming the supply of current to the battery when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
These and other features and advantages of the invention will become apparent to those of ordinary s~ill in the art upon review of the following detailed description of the preferred embodiment of the invention, which is given by way of example, reference being made to the appended drawings.
BRIEF DESCRIPTION OF THE
VIEWS OF THE DRAWINGS
Fig. l shows a circuit schematic of a battery charger embodying a first embodiment of the invention.
Fig. 2 shows a circuit schematic of an alternate embodiment of the invention.
Before these embod;ments of the invention are e~plained in detail, it is to be understood that the invention is not limited in its application to the details of construction, arrangement of components, and component values set forth in the following description or illustrated in the drawings. The invention is capable of o-ther em~odiments and of being practiced and carried out in various ways. Also, it i5 to be understood that the phraseology and terminology employed herein is for the purposa of description and should not be regarded as limiting.
DE~AILED DESCRIP~ION OF THE PREFERRED
EMBODIMENT OF THE INVENTION
Shown in Fig. 1 is a circuit schematic of a battery charger 10 embodying the invention. The charger 10 of the illustrated e~bodiment is adapted to be used with a standard twelve volt automotive battery 12 having a positive terminal 12A and a negative terminal 12B.
The battery charger l0 includes means for sensing the vol~age of the battery 12 when the battery 12 is electrically connected to the charger 10. In the preferred embodiment, the sensing means comprises a first and second voltage comparator IClA and Icls. The comparator IClA is used to determine if the sensed battery voltage is in excess of a first predetermined threshold voltage, and the comparator IClB is used to determine if the sensed battery voltage is below a second predetermined threshold voltage. Although the comparators IClA and IClB of the illustrated embodiment are part of a dual comparator package, discret~ comparator packages could be used.
.
:
2 ~
The battery charger 10 further includes a voltage divider compr.isinc3 resistors R13 and R14. The voltage across the battery 12 ~i.e. across the positive and negative terminals l~A and l2s, respective1y, of the battery) is applied, via a fuse F1 (included in the charger 10), to the voltage divider comprisinq R13 and R14. The charger 10 further includes an electrolytic capacitor C1 in parallel connection with the resistor R14, the parallel combination of R14 and Cl being connected between R13 and the negative terminal 12B of the batt:ery 12. The voltage that appears across the capacitor Cl, using the illustrated component values, is 41~ of the battery voltage and is applied to the non~inverting input, pin 3, of compara~or IClA, through a resistor R7 ~that i9 included in the charger 10). The voltage that appears across the capacitor Cl is also applied directly to the non-inverting input, pin 5, of the comparator IClB. The positive supply terminal, pin 8, of the co~parators IClA and IClB i~ connected to a positive supply voltage, which is preferably a regulated voltage. The n0gative supply terminal, pin 4, of the comparators IClA and IClB i5 connected to ground, in the illustrated embodiment. The output, pin 7, of the comparator IClB is connected to the non-inverting input, pin 3, of the comparator IClA via a s~itching diode D3 included in tha charger 10. More particularly, the anode of the diode D3 is connected to the non-inverting input, pin 3, of the comparator IClA, and the cathode of the diode D3 is connected to the output, pin 7, of the comparator IClB.
qhe battery charger 10 further includes a diode D1 having an anode connected to the output, pin 1, of the comparator IClA. The charger 10 further includes a resistor R2 connected be~ween the cathode of the diode Dl and the non-inverting input pin 3, of the comparator IClA.
The sensing means ~urther includes means for adjusting the first threshold voltage, the adjus~ing means comprising a continuously variable selector. In the illustratecl embodiment, the means for adjusting the first threshold voltage comprises a potentiometer P2 variable at the inverting input, pin 2, of comparator IClA and having one end connected to a reference voltage via a resistor R9, and another end connected to ground via a resistor R1, the resistors R1 and RS being included in the sensing means. Preferably, -the irst reference voltage is a regulated voltage, and when the illustrated component values are used, is regulated to be 6.8 volts.
The sensing means further comprises means for adjusting the second predetermined threshold voltage. More particularly, the means for adjusting the second predetermined threshold voltage comprises a continuously variable selector.
~ore particula~ly, the means for adjusting the second predetermined threshold voltaqe comprises a potentiometer P1 variable at the inverting input, pin 6, of the comparator IC1 and having one end connected to a second reference voltage via a resistor R16, and another end connected to ground via a resistor R15, the resistors R16 and R15 being included in the sensing means. Preferably, the second reference ~oltage is a regulated voltage, and, in the illustrated embodiment, the second reference voltage is the same as the first reference voltage.
Thus, the first and second predetermined threshold voltages, ~hich are used to determine ~hen the charger 10 should stop and start charging, as will be outlined below, can ~2~
be adjusted in view of battery type or temperature (a battery vol~age that represen~s a fully charged battery at one '!
~emperature does not necessarily represent a fully charged battery at another temper~ture). In one embodiment of the invention, the potentiometers Pl and P2 are acces.sible to the user of the charger 10. In another embodiment, P1 and P2 are adjustable by the manufacturer of the charger 10 (for use of the charger 10 with a specific type of battery, for example)~
Using the illustrated component values, the first predetermined . . .
threshold is ~djustable between 13.6 ~nd 16.2 VDC, and the second predetermined threshold is adjustable between 13.6 and i2.1 VDC.
The battery charger 10 further includes means for regulating voltage so that the first and second predetermined threshold voltages do not change. The illustrated voltage regulating means includes voltage regulator IC2, which provides ~8 volts (DC) in the illustrated embodiment, connected to the battery, and a zener diode D4 that is fed by the voltage regulator IC2, through a resistor R17 that is also included in the regulating means. In the illustrated embodiment, the diode D4 is a 6.8 volt zener diode. The 8 volts set by the voltage regulator IC2 supplies the comparators XClA and IClB at pin 8, while the 6.8 volts set by the zener diode D4 is used as the first and second reference voltage with the potentiometers Pl and P2. The first and second predetermined threshold voltages are thus kept stable over a range of variations of loads on the charger 10 and temperatures.
The voltage regulating means further includes a silicon rectifying blocking diode D2 supplying current to the voltage regulator IC2 from the positive terminal 12A of the ba~tery 12 via the fuse Fl. The diode D2 prevents the charger 10 from a~tempting to char~e the battery 12 if the battery is connec~ed back~ards and the battery voltage polarity is reversed. The voltage regulating means further includes a capacltor C2 connected between one end of the resistor R17 and ground, and a capacitor C3 connected between the other end of -the resistor R17 and ground, the capacitor C3 being provided to filter out potential electrical noises.
The battery charger 10 includes means for supplying charging current to the battery, the current supplying means being operab.le to alternatively 5upply current at a first and second rate, the first rate providing for high rate charying of the battery, i.e., at least 30, and preferably 40, charging amps - charging amps being defined as amps supplied to the battery while the battery is being charged as opposed to being boosted, and the second rate being at least 14, and preferably 15, charging amps.
In the illustrated embodiment, the current supplying means comprises a transformer X1,~ such as transformer having a primary winding XlA having a first end XlAA, a second end XlAC, and a tap XlA8 between the first end XlAA and the second end XlAC, and adapted to be electrically connected to household alternating current (e.g. 120 VAC), and a secondary winding XlB
adapted to be electrically connected to the hattery 12. In the illustrated embodiment, the ratio of the number of turns between the tap XlAB and the second end XlAC to the number of turns of the portion of the secondary winding XlB that can ~:
supply cu~rent to the battery 12 at any one time ~i.e. between the centertap of the secondary winding XlB and the anode of one of the diodes D6 or D7) is 7.88:1, and the ratio of the number .
, of turns of the entire primary winding XlA to t:he portion of the secondary wi.nding XlB that can supply current to the battery 12 at any one time (i.e. between the centertap of the secondary winding XlB and the anode of one of the diodes D6 or D7) is 9.41:1. The charger 10 includes diodes D6 and D7 having anodes respectively connected to opposite ends of the secondary winding XlB. The diodes D6 and D7 have cathodes that are adapted to be connected to the positive terminal 12A of the battery 12 to supply positive current to the positive terminal 12A. The secondary winding XlB includes a centertap collnected to the negative terminal 12B of the battery to supply negative current to the negative terminal 12B. The charger 10 optionally, but preferably, further includes an ammeter A
connected to the secondary winding XlB for series connection with the battery 12.
More particularly, in the .illustrated embodiment, when the first charging rate i.s selected, only the portion of the primary winding X1A between the tap XlAB and the end XlAC of the primary wincling XlA is energiæed with 120 volts of alternating current. When the second charging rate is selected, the entire primary winding XlA, between the ends XlAA
and XlAC, is selectively energiæed with 120 volts of alternating currentO
The charger 10 further includes means for severing (i.e., æero current, no trickle current) the supply of charging current from the transformer Xl to the battery 12 when the second charging rate is selected and when the sensing means senses battery voltage and for resuming the supply of current to the battery at the second charging rate when the severing means senses battery voltage below the second predetermined , 2~2~5~
threshold volta~e.
Al~hough one skilled in the art will readily realize that alternative embodiments are possible, the sensing means and the severing means of the illustrated embodiment are used exclusively when the second chargin~ rate has been selected.
In the illustrated embodiment, the severing means includes a relay K1 having contacts 23 and 22 operative to open to sever current flo~ through the primary winding of the transformer to sever the supply of charging current -to the battery when the sensing means senses battery voltage in excess of the first predetermined threshold voltage. In the illustrated embodiment, the relay!K1 is rated for 10 amps through and 120 volts AC across the contacts 20 and 22. The relay Kl further includes a coil 24. Application of 12 vol~s across the coi.l ~4 results in the clo~ing of the contacts 20 and 22. ~he contacts 20 and 22 open when the coil 24 is not energized (i.e. when no voltage is applied across the coil 24). The coil 24 has a first end 26 connected to the cathode of diode D2, and a second end 28. The contact 20 is connected to the end XlAA of the primary winding XlA.
The severing means further includes a correct transistor Ql having an emitter connected to the voltage regulating means. More particularly, the emitter of -the transistor Ql is connected to the ~8 volts output of the regulating means. The transistor Ql also has a base connected to the output, pin 1, of the comparator IClA, via resistor R4.
The severing means further includes a resistor R5 connected between the emltter and the base of the transistor Q1, as well as a resistor ~3 connected between the emitter of the transistor Ql and the output pin 1, of the comparator IClA.
The sev~ing means further includes a npn transistor Q2 having an emitter connected to ground, a collector, and a base. The severing means ~urther includes a resistor R11 connected between the base and the emitter of the transistor Q2j and a resistor ~10 connected between the c:ollector of transistor Ql and the base of transistor Q2. The severing means further includes a resistor R12 connected between the collector of the transistor Q2 and the end 28 of the coil 24.
The severing means further includes a diode DS having a anocle connected to the end 28 of the coil 24, and a cathode connected to the end 26 of the coil 24.
In operation, when the voltage of the battery 12 is less than or equal to the threshold voltage set by the potentiometer P1, then the output, pin 7, of IClB is pulled down to zero volts. This pulls the non-inverting input, pin 3, of the comparator IClA low through the switching diode D3, and causes the voltage at the output, pin 1, of the comparator IClA
to be pulled down to zero volts. This turns on the pnp transistor Q1 which turns on the npn transistor Q2, thereby resulting in the coil 24 of the relay Kl being energized. When the battery becomes charged, the output, pin 7 of the comparator IClB will go to +8 VDC, causing the switching diode D3 to be back-biased. This causes the voltage at the non-inverting input, pin 3, of the comparator IClA to be governed by the voltage across the electrolytic capacitor Cl through the input resistor R7. When the voltage of the battery 12 reaches the threshold voltage set by the potentiometer P2, the output, pin 1 of the comparator IClA will become +8 VDC.
This turns off the transistors Ql and Q2r de-energizing the relay Xl and thus disconnecting the 120 VAC source from the ~2~ 6 primary XlA of ~he transEormer X1 of the charger. The sensing means, regulatinq ~eans, and severing means are powered by the battery 12 when the charger lO is off (i.e. 120 VAC is not applied to the primary of the charying transf~rmer), and are powered by the charger when the charger is on.
The battery charger 10 urther includes means for alternatively selecting the first charging rate and the second charging rate.
The battery charger 10 includes lines 50 and 52 adapted to be connected -to a hot and a neutral line, respectively, of the source of household 12~ volt alternating current. In the preferred embodiment, the lines 50 and 52 terminate in a 3-pronged connector for connection to the hot and neutral lines. The 3-pronged connector preferably has a ground pin connected in a conventional fashion to a cabinet (not shown) housing the battery charger 10. The line 50 is connected to an end XlAC of the transformer primary winding XlA.
The means for selecting the first charging rate and the second charging rate comprises a switch SW manually movable (by the user of the battery charger) between a position 62 thigh or fask charge mode~ and a position 64 (automatic mode) to connect the lead 52 to the tap XlAB or to the contact 22, respectively. When the switch SW is moved to the position 62, 120 volts of alternating current is provided to the transformer primary between the tap XlAB and the end XlAC. When the switch SW is ~oved to the position 64, 120 volts of alternating current is provided to the transformer primary between the ends XlAA and XlAC, when khe con-tacts 20 and 22 are closed.
Thus, means are provided for alternatively selecting the first charging rate and thP second charging rate.
20~5~
-16~
Ir~ ~he preferred embodiment, the switch SW is further manually movable to an "off" position 60 to disconnect the lead 52 from the transformer primary XlA.
The batte~y charger lO further includes first, second, and third discrete visual indlcators, means for illuminating the irst indicator in response to the battery charger ~eing connected to the source of alternating current, means for illuminating the second indicator while the supplying means supplies charging current to the battery at the second current rate, and means for illuminating the third indicator in response to the severing means severing the supply of charging cur~ent to the battery while the second (i.e. automatic) charging rate has been selected. The third indicator, when illuminated by the third mentioned illuminating means, thereby provides a visual indication that the second charging rate (i.e. automatic mode~ has been selected, and that the current supplying means will resume the supply of charging current to the battery when the sensing means senses battery voltage below the second predetermined ~oltage. More particularly, in the illustrated embodiment, the first visual indicator is a red neon light, NEl, connected in the battery charger 10 between the leads 50 and 52, the second visual indicator is an amber neon light NE2, connected across the primary winding XlA of the transformer Xl, between the ends XlAA and XlAC, and the third visual indicator is a green neon light NE3 having one end connected to the contact 20 and another end connected to the contact 22. Thus, by way of electrical connections in the battery charger 10, means are provided for llluminating the fixst indicator in response to the battery charger being connected to the source of alternating current, for illumillating ~he second indicator while the supplying means sopplies charging current to the ba-ttery at the second current rate, and for illuminating the third indicator in response to the severing means severing the supply of charcling current to the battery while the second li.e. automatic~ charging xate has been selected. The third indicator, when illuminated by the third mentioned illuminating means, thereby provides the visual indication that the second charging rate (i.e. autornatic mode) has been selected, and that the current supplying means will resume the supply of charginq current to the battery when the sensing means senses battery voltage below the second predetermined voltage. The red, amber, and green neon indicators are preferably arranged vertically or horizontally in traffic light order.
The battery charger lO of the preferred embodiment of the invention includes a fan 70 connected between the tap XlAB
of the transformer primary and the lead 50, and operative to cool the battery charger lO ~hen the means for selectively and alternatively connecting the first and second charging means to the battery l2 connects the first charging means to the battery 12.
Shown in Fig. 2 i9 an alternative embodiment of the invention, a portion of which is identical to the embodiment shown in Fig. l, like reference numerals indicating like componen~s~ which portion will not again be described in detail.
In the alternative embodiment of the in~ention sho~n in Fig. 2, the means for alternatively selecting the first charging rate and the second charqing rate comprises timer means, including a timer motor, for selectinq the first rate for a selected period of time and for selecting the second rate 2 ~
after the selectecl period of time expires. More particularly, in the illllstrated embodiment, the timer means comprises a timer Tl operati.ve to connect the lead 52 to the tap XlAB (fast charge mode) for a per~od of time selected by the user of the battery charger 10, and to thereafter connect the lead S2 to the contact 22 (automatic mode). The timer T1 can also be operated by the user of the battery charger 10 to connect the second charging means to the battery without the first current supplying means first being connected to the battery 12. An appropriate timer Tl is an electromechanical timer such as Model CX 43706 by Ma].lory Timers, Valparaiso, Indiana; or Model MS 65 by Corpono and Pons (divisiorl of Eaton Controls Products), 76530 Grand-Couronne, France.
Various of the features of the invention are set forth in the following clai~s.
Claims (53)
1. A battery charger adapted to be electrically connected to the terminals of a battery for providing a charge to the battery, the battery charger comprising:
means for supplying charging current to the battery, the current supplying means being operable to alternatively and selectively supply current at a first and second rate, the first rate providing for high rate charging of the battery;
means for sensing the voltage of the battery while the charger is connected to the battery, the sensing means being adapted to be coupled to the battery;
means for alternatively selecting the first rate and the second rate, the selecting means being coupled to the supplying means;
means for severing the supply of charging current to the battery when the second rate is selected and when the sensing means senses battery voltage in excess of a first predetermined threshold voltage, and for resuming the supply of current to the battery at the second rate when the sensing means senses battery voltage below a second predetermined threshold voltage lower than the first predetermined threshold voltage, the severing means being coupled to the current supplying means, to the sensing means, and to the selecting means.
means for supplying charging current to the battery, the current supplying means being operable to alternatively and selectively supply current at a first and second rate, the first rate providing for high rate charging of the battery;
means for sensing the voltage of the battery while the charger is connected to the battery, the sensing means being adapted to be coupled to the battery;
means for alternatively selecting the first rate and the second rate, the selecting means being coupled to the supplying means;
means for severing the supply of charging current to the battery when the second rate is selected and when the sensing means senses battery voltage in excess of a first predetermined threshold voltage, and for resuming the supply of current to the battery at the second rate when the sensing means senses battery voltage below a second predetermined threshold voltage lower than the first predetermined threshold voltage, the severing means being coupled to the current supplying means, to the sensing means, and to the selecting means.
2. A battery charger as set forth in claim 1 wherein the second current rate is at least 14 amps.
3. A battery charger as set forth in claim 1 wherein the means for selectively and alternatively connecting includes mechanically operable switch means including means for selecting the first current rate and the second current rate.
4. A battery charger as set forth in claim 1 wherein the first current rate is at least 30 amps.
5. A battery charger as set forth in claim 1 wherein the first current rate is approximately 40 amps.
6. A battery charger as set forth in claim 1 and further comprising means for adjusting the first predetermined threshold voltage, the adjusting means comprising a continuously variable selector.
7. A battery charger as set forth in claim 1 and further comprising means for adjusting the second predetermined threshold voltage.
8. A battery charger as set forth in claim 7 wherein the means for adjusting the second predetermined threshold voltage comprises a continuously variable selector.
9. A battery charger as set forth in claim 1 wherein the first predetermined threshold voltage is greater than 13.6 volts and the second predetermined threshold voltage is less than 13.6 volts.
10. A battery charger as set forth in claim 1 wherein the first predetermined threshold voltage is approximately 14.4 volts and the second predetermined threshold voltage is approximately 12.8 volts.
11. A battery charger as set forth in claim 1, further adapted to be connected to a source of household alternating current and further including first, second, and third discrete visual indicators, means for illuminating the first indicator in response to the battery charger being connected to the source of alternating current, means for illuminating the second indicator while the current supplying means supplies charging current to the battery at the second current rate, and means for illuminating the third indicator in response to the severing means severing the supply of charging current to the battery while the second charging rate has been selected.
12. A battery charger as set forth in claim 1 wherein the current supplying means comprises a transformer having a primary winding adapted to be electrically connected to household alternating current, and a secondary winding adapted to be electrically connected to the battery, wherein the severing means includes relay contacts operative to open to sever current flow through the primary winding of the transformer to sever the supply of charging current to the battery when the sensing means senses battery voltage in excess of the upper predetermined threshold voltage.
13. A battery charger adapted to be electrically connected to the terminals of a battery for providing a charge to the battery, the battery charger comprising:
means for supplying a charging current to the battery, the current supplying means being operable to alternatively and selectively supply current at a first and second rate, the first current rate being at least 30 amps and providing for high rate charging of the battery;
means for sensing the voltage of the battery when the charger is connected to the battery, the sensing means being adapted to be coupled to the battery;
timer means for selecting the first rate for a selected period of time, and for selecting the second rate after the selected period of time expires, the timer means being coupled to the supplying means; and means for severing the supply of charging current to the battery when the second rate is selected and when the sensing means senses battery voltage in excess of a first predetermined threshold voltage, and for resuming the supply of charging current to the battery at the second rate when the sensing means senses battery voltage below a second predetermined threshold voltage lower than the first predetermined threshold voltage, the severing means being coupled to the current supplying means, to the sensing means, and to the timer means.
means for supplying a charging current to the battery, the current supplying means being operable to alternatively and selectively supply current at a first and second rate, the first current rate being at least 30 amps and providing for high rate charging of the battery;
means for sensing the voltage of the battery when the charger is connected to the battery, the sensing means being adapted to be coupled to the battery;
timer means for selecting the first rate for a selected period of time, and for selecting the second rate after the selected period of time expires, the timer means being coupled to the supplying means; and means for severing the supply of charging current to the battery when the second rate is selected and when the sensing means senses battery voltage in excess of a first predetermined threshold voltage, and for resuming the supply of charging current to the battery at the second rate when the sensing means senses battery voltage below a second predetermined threshold voltage lower than the first predetermined threshold voltage, the severing means being coupled to the current supplying means, to the sensing means, and to the timer means.
14. A battery charger as set forth in claim 13 wherein the second current rate is at least 14 amps.
15. A battery charger as set forth in claim 13 wherein the first current rate is at least 30 amps.
16. A battery charger as set forth in claim 13 wherein the first current rate is approximately 40 amps.
17. A battery charger as set forth in claim 13 and further comprising means for adjusting the first predetermined threshold voltage, the adjusting means comprising a continuously variable selector.
18. A battery charger as set forth in claim 13 and further comprising means for adjusting the second predetermined threshold voltage.
19. A battery charger as set forth in claim 18 wherein the means for adjusting the second predetermined threshold voltage comprises a continuously variable selector.
20. A battery charger as set forth in claim 13 wherein the first predetermined threshold voltage is greater than 13.6 volts and the second predetermined threshold voltage is less than 13.6 volts.
21. A battery charger as set forth in claim 13 wherein the first predetermined threshold voltage is approximately 14.4 volts and the second predetermined threshold voltage is approximately 12.8 volts.
22. A battery charger as set forth in claim 13, further adapted to be connected to a source of household alternating current, and further including first, second, and third discrete visual indicators, means for illuminating the first indicator in response to the battery charger being connected to the source of alternating current, means for illuminating the second indicator while the supplying means supplies charging current to the battery at the second current rate, and means for illuminating the third indicator in response to the severing means severing the supply of charging current to the battery while the second charging rate has been selected.
23. A battery charger as set forth in claim 13 wherein the current supplying means comprises a transformer having a primary winding adapted to be electrically connected to household alternating current, and a secondary winding adapted to be electrically connected to the battery, wherein the severing means includes relay contacts operative to open to sever current flow through the primary winding of the transformer to sever the supply of charging current to the battery when the sensing means senses battery voltage in excess of the upper predetermined threshold voltage.
24. A battery charger comprising:
means for sensing the voltage of a battery when a battery is electrically connected to the charger;
means for supplying at least 14 amps of charging current to the battery;
means for severing the supply of charging current to the battery when the sensing means senses battery voltage in excess of a first predetermined threshold voltage and for resuming the supply of at least 14 amps of charging current to the battery when the severing means senses battery voltage below a second predetermined threshold voltage lower than the first predetermined threshold voltage, the severing means being coupled to the current supplying means and to the sensing means.
means for sensing the voltage of a battery when a battery is electrically connected to the charger;
means for supplying at least 14 amps of charging current to the battery;
means for severing the supply of charging current to the battery when the sensing means senses battery voltage in excess of a first predetermined threshold voltage and for resuming the supply of at least 14 amps of charging current to the battery when the severing means senses battery voltage below a second predetermined threshold voltage lower than the first predetermined threshold voltage, the severing means being coupled to the current supplying means and to the sensing means.
25. A battery charger as set forth in claim 24, said sensing means further comprising means for adjusting the first threshold voltage, the adjusting means comprising a continuously variable selector.
26. A battery charger as set forth in claim 24, said sensing means further comprising means for adjusting the second predetermined threshold voltage.
27. A battery charger as set forth in claim 26 wherein the means for adjusting the second predetermined threshold voltage comprises a continuously variable selector.
28. A battery charger as set forth in claim 24 wherein the first predetermined threshold voltage is greater than 13.6 volts and the second predetermined threshold voltage is lower than 13.6 volts.
29. A battery charger as set forth in claim 24 wherein the first predetermined threshold voltage is approximately 14.4 volts and the lower predetermined threshold voltage is approximately 12.8 volts.
30. A battery charger as set forth in claim 24, further adapted to be connected to a source of household alternating current and further including first, second and third discrete visual indicators, means for illuminating the first indicator in response to the battery charger being connected to the source of alternating current, means for illuminating the second indicator while the supplying means supplies charging current to the battery, and means for illuminating the third indicator in response to the severing means severing the supply of charging current to the battery while the second charging rate has been selected.
31. A battery charger as set forth in claim 24 wherein the current supplying means comprises a transformer having a primary winding adapted to be electrically connected to household alternating current, and a secondary winding adapted to be electrically connected to the battery, wherein the severing means includes relay contacts operative to open to sever current flow through the primary winding of the transformer to sever the supply of charging current to the battery when the sensing means senses battery voltage in excess of the first predetermined threshold voltage.
32. A method of charging a battery comprising the steps of:
providing means for supplying charging current to the battery, the current supplying means being operable to alternatively supply current at a first rate and at a second rate;
selecting one of the first rate and the second rate;
electronically severing the supply at charging current to the battery when the second rate is selected and when the battery voltage exceeds a first predetermined threshold voltage; and electronically resuming the supply of current to the battery at the second rate when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
providing means for supplying charging current to the battery, the current supplying means being operable to alternatively supply current at a first rate and at a second rate;
selecting one of the first rate and the second rate;
electronically severing the supply at charging current to the battery when the second rate is selected and when the battery voltage exceeds a first predetermined threshold voltage; and electronically resuming the supply of current to the battery at the second rate when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
33. A method in accordance with claim 32 wherein the second current rate is at least 14 amps.
34. A method in accordance with claim 32 wherein the first current rate is at least 30 amps.
35. A method in accordance with claim 32 and further including the step of adjusting the first predetermined threshold voltage.
36. A method in accordance with claim 32 and further including the step of adjusting the second predetermined threshold voltage.
37. A method in accordance with claim 32 wherein the first predetermined threshold voltage is greater than 13.6 volts and the second predetermined threshold voltage is less than 13.6 volts.
38. A method in accordance with claim 32 wherein the first predetermined threshold voltage is approximately 14.4 volts and the second predetermined threshold voltage is approximately 12.8 volts.
39. A method in accordance with claim 32 and further including the steps of illuminating a visual indicator when current is supplied at the second rate, and illuminating a visual indicator when the supply of charging current has been severed while the second current rate has been selected.
40. A method of charging a battery comprising the steps of:
providing means for supplying charging current to the battery, the current supplying means being operable to selectively supply current at a first rate of at least 30 amps and at a second rate;
selecting the first rate for a selected period of time and thereafter selecting the second rate;
electronically severing the supply of charging current to the battery when the second rate is selected and when the battery voltage exceeds a first predetermined threshold voltage; and electronically resuming the supply of current to the battery at the second rate when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
providing means for supplying charging current to the battery, the current supplying means being operable to selectively supply current at a first rate of at least 30 amps and at a second rate;
selecting the first rate for a selected period of time and thereafter selecting the second rate;
electronically severing the supply of charging current to the battery when the second rate is selected and when the battery voltage exceeds a first predetermined threshold voltage; and electronically resuming the supply of current to the battery at the second rate when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
41. A method in accordance with claim 40 wherein the second current rate is at least 14 amps.
42. A method in accordance with claim 40 wherein the first current rate is at least 30 amps.
43. A method in accordance with claim 40 and further including the step of adjusting the first predetermined threshold voltage.
44. A method in accordance with claim 40 and further including the step of adjusting the second predetermined threshold voltage.
45. A method in accordance with claim 40 wherein the first predetermined threshold voltage is greater than 13.6 volts and the second predetermined threshold voltage is less than 13.6 volts.
46. A method in accordance with claim 40 wherein the first predetermined threshold voltage is approximately 14.4 volts and the second predetermined threshold voltage is approximately 12.8 volts.
47. A method in accordance with claim 40 and further including the steps of illuminating a visual indicator when current is supplied at the second rate, and illuminating a visual indicator when the supply of charging current has been severed while the second current rate has been selected.
48. A method of charging a battery comprising the steps of:
providing means for supplying at least 14 amps of charging current to the battery;
electronically severing the supply of charging current to the battery when the battery voltage exceeds a first predetermined threshold voltage; and electronically resuming the supply of current to the battery when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
providing means for supplying at least 14 amps of charging current to the battery;
electronically severing the supply of charging current to the battery when the battery voltage exceeds a first predetermined threshold voltage; and electronically resuming the supply of current to the battery when the battery voltage falls below a second predetermined threshold voltage lower than the first predetermined threshold voltage.
49. A method in accordance with claim 48 and further including the step of adjusting the first predetermined threshold voltage.
50. A method in accordance with claim 48 and further including the step of adjusting the second predetermined threshold voltage.
51. A method in accordance with claim 48 wherein the first predetermined threshold voltage is greater than 13.6 volts and the second predetermined threshold voltage is less than 13.6 volts.
52. A method in accordance with claim 48 wherein the first predetermined threshold voltage is approximately 14.4 volts and the second predetermined threshold voltage is approximately 12.8 volts.
53. A method in accordance with claim 48 and further including the steps of illuminating a visual indicator when the supply of charging current at the second rate is severed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/508,345 US5168205A (en) | 1990-04-04 | 1990-04-04 | Method and apparatus for charging a battery in high amp and automatic charging modes |
| US508,345 | 1990-04-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2024656A1 true CA2024656A1 (en) | 1991-10-05 |
Family
ID=24022382
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002024656A Abandoned CA2024656A1 (en) | 1990-04-04 | 1990-09-05 | Method and apparatus for charging a battery in high amp and automatic charging modes |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US5168205A (en) |
| CA (1) | CA2024656A1 (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5297664A (en) * | 1992-06-26 | 1994-03-29 | Tseng Ling Yuan | Electric charging/parking meter |
| FI96370C (en) * | 1992-10-01 | 1996-06-10 | Fps Power Systems Oy Ab | Method for checking the internal impedance of a backup power supply battery and a backup power supply |
| US5504416A (en) * | 1993-12-15 | 1996-04-02 | Unitrode Corporation | Battery charger circuit including battery temperature control |
| US5652501A (en) * | 1994-12-12 | 1997-07-29 | Unitrode Corporation | Voltage sensor for detecting cell voltages |
| US5581170A (en) * | 1994-12-12 | 1996-12-03 | Unitrode Corporation | Battery protector |
| KR970055044A (en) * | 1995-12-05 | 1997-07-31 | 김광호 | Battery charger supports multiple charging methods |
| US5844399A (en) * | 1996-07-26 | 1998-12-01 | The University Of Toledo | Battery charger control system |
| KR100263551B1 (en) * | 1996-10-12 | 2000-08-01 | 윤종용 | Secondary battery charging circuit |
| KR100222074B1 (en) * | 1996-12-17 | 1999-10-01 | 윤종용 | Constant power charging circuit and portable computer using the same |
| EP0849660B1 (en) * | 1996-12-19 | 2004-10-27 | Koninklijke Philips Electronics N.V. | Portable electronic apparatus with a device for detecting a variation in the supply voltage |
| US5864221A (en) * | 1997-07-29 | 1999-01-26 | Trw Inc. | Dedicated avionics standby power supply |
| KR100281528B1 (en) * | 1998-04-29 | 2001-02-15 | 윤종용 | Power supply circuit |
| US7193393B1 (en) * | 2001-10-26 | 2007-03-20 | Payne James C | Approach for charging multiple batteries |
| US20100190052A1 (en) * | 2009-01-27 | 2010-07-29 | Umesh Rajani | Battery pack with high and low current discharge terminals |
| US8598846B1 (en) * | 2009-04-07 | 2013-12-03 | The University Of Akron | Device and method for stabilizing a battery pack |
| US8575779B2 (en) | 2010-02-18 | 2013-11-05 | Alpha Technologies Inc. | Ferroresonant transformer for use in uninterruptible power supplies |
| US8269641B2 (en) | 2010-06-07 | 2012-09-18 | Lear Corporation | Vehicle power management system |
| WO2012148512A1 (en) | 2011-01-23 | 2012-11-01 | Alpha Technologies Inc. | Switching systems and methods for use in uninterruptible power supplies |
| US8864373B2 (en) * | 2011-09-12 | 2014-10-21 | National Semiconductor Corporation | Small highly accurate battery temperature monitoring circuit |
| US9234916B2 (en) | 2012-05-11 | 2016-01-12 | Alpha Technologies Inc. | Status monitoring cables for generators |
| JP5960280B2 (en) * | 2012-11-07 | 2016-08-02 | 三洋電機株式会社 | Charger |
| CA2997953A1 (en) | 2015-09-13 | 2017-03-16 | Alpha Technologies Inc. | Power control systems and methods |
| US10381867B1 (en) | 2015-10-16 | 2019-08-13 | Alpha Technologeis Services, Inc. | Ferroresonant transformer systems and methods with selectable input and output voltages for use in uninterruptible power supplies |
| WO2019014682A1 (en) | 2017-07-14 | 2019-01-17 | Alpha Technologies Inc. | Voltage regulated ac power supply systems and methods |
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|---|---|---|---|---|
| GB892954A (en) * | 1959-03-05 | 1962-04-04 | Nat Res Dev | Automatic battery charger |
| DE1816562A1 (en) * | 1968-12-23 | 1970-06-25 | Schickedanz Kg G | Automatic battery charger |
| GB1309394A (en) * | 1970-01-27 | 1973-03-07 | Macharg J A | Battery chargers |
| US3678363A (en) * | 1970-04-06 | 1972-07-18 | Globe Union Inc | Automatic battery charger with multiple rate charging |
| US3688177A (en) * | 1971-03-25 | 1972-08-29 | Westinghouse Electric Corp | Battery charger |
| US3699422A (en) * | 1972-02-11 | 1972-10-17 | Honeywell Inc | Automatic battery charger |
| US4392101A (en) * | 1978-05-31 | 1983-07-05 | Black & Decker Inc. | Method of charging batteries and apparatus therefor |
| GB2028029A (en) * | 1978-08-09 | 1980-02-27 | Lucas Industries Ltd | Traction battery charging system |
| US4270080A (en) * | 1978-12-14 | 1981-05-26 | Sun Electric Corporation | Automatic battery charge apparatus and method |
| US4341988A (en) * | 1980-06-25 | 1982-07-27 | Emhart Industries, Inc. | Voltage level detector for battery charger control circuit |
| GB2080642A (en) * | 1980-07-23 | 1982-02-03 | Lucas Industries Ltd | Battery charging system |
| US4583035A (en) * | 1984-03-05 | 1986-04-15 | Sloan Albert H | Apparatus for monitoring and charging electric storage battery |
| US4742290A (en) * | 1986-06-02 | 1988-05-03 | Acme Electric Corporation | Recharging battery charger |
| US5055763A (en) * | 1988-09-26 | 1991-10-08 | Eveready Battery Company, Inc. | Electronic battery charger device and method |
-
1990
- 1990-04-04 US US07/508,345 patent/US5168205A/en not_active Expired - Lifetime
- 1990-09-05 CA CA002024656A patent/CA2024656A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US5168205A (en) | 1992-12-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |