FR2683685A1 - Charger for a bank of accumulators, especially for a pleasure boat - Google Patents

Abstract

The invention relates to a charger for a bank of accumulators. It relates to a charger which comprises an input (16) for alternating current, a transformer, a rectifier, a rectified current output (18, 20), a regulator, at least one control device (32, 34, 44) and at least one indicator device (38 to 42). According to the invention, the regulator is arranged between the input and the transformer, the transformer, the rectifier and the rectified current output are at a first location (10) and the control device at least and the indicator device are at a second location (12) distant from the first one. Application to chargers for pleasure boats.

Description

 The present invention relates to a battery charger. More specifically, it relates to such a charger intended for applications in which the storage batteries which must be charged are located in a location which is difficult to access. It also relates to a battery charger having a certain number of safety and regulation characteristics making it particularly suitable for these applications.

 Numerous chargers for accumulator batteries are already known, the characteristics of which depend on the intended application. Many chargers are intended for low capacity accumulator batteries, of the order of a few ampere-hours at most, these batteries being intended for supplying portable electrical or electronic devices for example. These devices pose specific problems.

 Other chargers are intended for supply batteries of very large groups of batteries, with capacities of several thousand ampere-hours.

These installations require special characteristics, and the monitoring of batteries and battery groups poses specific problems in particular.

 Finally, chargers are known which are intended for accumulator batteries whose capacity is from a few tens to a few hundred ampere-hours. These storage batteries are generally intended for supplying small or medium-sized installations, for example electric power supplies for pleasure boats, vehicles or small installations.

 The invention relates to chargers of the latter type, that is to say intended for batteries and groups of batteries having a medium capacity, especially when the batteries have to be placed in a location which is difficult to access.

 More specifically, the invention is described in its application to a battery charger intended for a pleasure boat. Given the consumption of electrical energy, the only storage batteries that can reasonably be considered for use on such pleasure boats are lead acid storage batteries, taking into account their cost. However, these storage batteries are heavy. As the balance of masses is essential on a pleasure boat, accumulator batteries are usually placed as low as possible, most often at the bottom of the bilge, near the propulsion engine which is also an element heavy and therefore placed as low as possible in the hull of the boat.

 Given this arrangement of storage batteries as low as possible in the hull, in general in a rear compartment which is accessible only by a narrow cover, it is difficult to have access to storage batteries. However, these must be charged, most often from an electrical outlet on a pontoon, when the pleasure boat is moored at the port. A problem then arises, because either the battery charger is placed at a distance from the batteries, in a place where it can be easily observed for the control and monitoring of the indications which it gives, but the wires connecting the charger to the batteries are long and then present a high release of heat and significant losses, or the charger is placed very close to the storage batteries, but this arrangement then makes it difficult to control and monitor the progress of the charge.

 An attempt has therefore been made to separate the functions of charge proper and of charge control and monitoring. To this end, a control button or an ammeter has already been placed on a dashboard remote from the charger, itself placed near the accumulator batteries. However, this switch or this ammeter is added to those of the charger which is placed near the accumulator batteries. In addition, this solution, if it allows some remote control and monitoring, is costly since it amounts to doubling certain elements of the battery charger.

 In a first aspect, the invention relates to a battery charger which does not pose the aforementioned problem.

More specifically, in this first aspect, the invention relates to a battery charger in which the essential elements, that is to say the transformer, the rectifier and possibly the regulator, are placed near the battery. or accumulator batteries to be charged, while the control devices and the indicating devices are at a second location remote from the battery or accumulator batteries, usually at a navigation station of the pleasure boat.

 More specifically, the invention relates to a battery charger, of the type which comprises an alternating current input, a transformer intended to receive the alternating current coming from the entry, a rectifier intended to receive an alternating current from the transformer and forming a unidirectional current, an unidirectional current output from the rectifier, a charger operation regulator, at least one control device and at least one indicating device; according to the invention, the regulator is arranged between the input and the transformer, the transformer, the rectifier and the unidirectional current output are in a first location, and the control device at least and the indicating device are in a second location distant from the first.

 Preferably, the current input is in the second location, and the regulator is in the first location.

In addition, it advantageously comprises at least one fuse mounted between the input and the transformer and arranged in the second location.

 It is advantageous that the first location is very close to the storage batteries which must be charged by the charger, and that the second location is close to a control or navigation station.

 Preferably, the control device comprises at least one device chosen from a power control switch, a regulator control potentiometer, and a reset switch, and the indicating device comprises at least one indicating device chosen from a ammeter giving the intensity of the unidirectional current, a charge indicator, a standby indicator and a fault indicator.

 In many applications of the aforementioned types, for example in pleasure craft, several batteries or groups of accumulator batteries are used. More specifically, it is frequent, in this application to pleasure craft, that a first group of accumulator batteries is used to supply the engine, when the latter is running, and that a second group is used for the other uses, for example for lighting, for powering navigation instruments, etc. As a result, one group of batteries is usually less charged than another group, and it is important that after charging the two groups of batteries are both charged in the same way without one ever being able to discharge in the other. It is therefore desirable that the charging is carried out according to a well defined program, according to which the charging is carried out at constant current until all the battery groups reach at least a high value, for example 14.4 V in the lead acid storage batteries, without however exceeding a high safety cut-off value, for example of 15.6 V. Equalization, that is to say a charge at constant voltage, of 14.4 V in the case under consideration, then makes it possible to obtain analogous voltages in all the battery groups. Charging is resumed as soon as the voltage across a battery group drops to a reduced value, for example 11.9 V. However, charger operation is interrupted when the voltage across any battery group is lower than a low cut-off value, for example 4 V.

 More specifically, when the charger is intended to charge at least two batteries or groups of batteries, it has a number of unidirectional current outputs equal to the number of batteries or groups of batteries, and each output is connected by a diode to the output rectifier. After charging at constant current, the regulator ensures voltage equalization between the batteries or groups of batteries, that is to say charging at constant voltage.

 Preferably, the regulator is intended to ensure charging until the voltage at the terminals of the battery, of the battery group, of each battery or of each group of batteries rises to a high value, then to ensure a new charge when the voltage at the terminals of the battery, of the battery group, of each battery or of each group of batteries has dropped to a reduced value.

 It is also advantageous for the regulator to interrupt charging when the voltage at the terminals of the battery, of the battery group, of a battery or of a battery group exceeds a high cut-off value which is higher than said high value.

 It is also advantageous for the regulator to interrupt charging when the voltage across the battery, the battery group, at least one battery or at least one battery group falls below a low cut-off value. which is less than said reduced value.

 In all of these embodiments, it is preferable that the voltage is detected directly at the terminals of the battery or of the battery group.

 In another aspect, the invention relates to a battery charger having safety characteristics which are added to the safety given by the charging program. More specifically, the charger comprises a thermosensitive device, comprising for example a thermal switch, preventing excessive heating of the charger. Likewise, it includes safety devices ensuring protection against overloads and preventing the charger from operating in the event of a regulator failure.

 More specifically, the charger preferably comprises a thermosensitive safety device intended to interrupt the unidirectional current when the temperature of a part of the charger reaches a predetermined value. This thermosensitive device advantageously causes the resumption of the unidirectional current transmission when the detected temperature reaches a second temperature lower than the first.

 It is also advantageous for the charger to include a safety device intended to interrupt the supply to the charger in the event of a power supply failure of the regulator, and / or for it to include a safety device independent of the regulator and intended to ensure protection against voltage overloads.

Other characteristics and advantages of the invention will emerge more clearly from the description which will follow in the embodiment, made with reference to the appended drawings in which
FIG. 1 is a schematic view in part in perspective of a battery charger according to the invention, associated with two groups of batteries,
FIG. 2 is a detailed diagram of the part of the battery charger placed near the accumulator batteries to be charged; and
Figures 3a and 3b show the control elements and indicators of the charger of Figure 1, placed in the indicator and control part.

 Figure 1 shows the general arrangement of a battery charger according to the invention. We consider its application to a pleasure boat. In this case, the body 10 of the charger, containing in particular the transformer and the rectifier, is placed at the bottom of the boat, near the accumulator batteries, and the control and indicator box 12 is placed at the navigation station, it that is to say at a fairly high location, just below the bridge. The body 10 and the box 12 are connected by wires 14. Finally, wires 16 reaching the control box 12 transmit the alternating current, for example at 220 V, taken from a socket on a mooring pontoon.

 The body 10 of the charger has three output terminals in this embodiment, that is to say a terminal 18 for output from a first charging circuit, a terminal 20 for output from a second circuit charging station and a common negative terminal 22. In this embodiment, a battery charger ensuring the supply of two groups of batteries 24, 26 is therefore considered. However, the charger according to the invention can be used with a single battery or a single group of batteries, one of the terminals 18 and 20 then being unnecessary.

It can also charge a larger number of battery groups, and in this case, the charger includes a greater number of unidirectional current outputs, such as 18, 20.

 Also shown are terminals 28 which are connected to the positive and negative terminals of the battery groups 24, 26. The connecting wires of the terminals of the battery groups to the terminals 28 allow a direct measurement of the voltage across the terminals of each battery group . This measurement is unnecessary when the wires between the terminals 18, 20, 22 of the body 10 and the storage batteries 24, 26 are very short. However, if their length exceeds a few meters, there is a voltage drop in these supply wires and it is therefore desirable to use separate wires, connected to the terminals 28, to obtain an accurate voltage measurement.

 We have also schematically indicated, by the reference 30, the presence of ventilation openings because there is obviously a release of heat inside the body 10.

 The control box 12 includes all the control devices and indicators to which access is desirable. It should however be noted that, in other embodiments, only some of these control devices and indicators can be placed in the control box 12. In the embodiment considered, the control elements essentially comprise a switch 32, preferably a bipolar switch, advantageously provided with a warning lamp indicating the presence of a supply voltage.

Another control element is the button 34 for controlling a potentiometer for adjusting the intensity of the charging current. The intensity set is indicated on an ammeter 36 which constitutes one of the indicating devices. Another indicating device is constituted by a witness 38, for example a photoemissive diode, of green color. During charging, this diode is permanently on and, during the battery equalization step, which follows charging, this indicator 38 advantageously flashes. Another indicating device is constituted by a witness 40, for example a red photoemissive diode, which indicates the standby state of the charger, that is to say the state after an equalization step and before the resumption of the load.

Finally, another indicating device is constituted by another indicator 42 which is lit in the event of a fault, as described in more detail below. Finally, the housing 12 also includes, on its front panel, another control device 44 which is a simple push-button contact allowing a "reset to zero", that is to say the execution of various operations described in detail in the following, for example resumption of the charge before the voltage of a group of batteries has fallen below a predetermined value. A fuse 46 is accessible on the front face of this control unit, if necessary.

 FIG. 2 represents in greater detail the essentials of the elements housed in the body 10, while FIGS. 3a and 3b represent the essentials of the elements housed in the control unit 12.

 In particular, in FIGS. 3a and 3b, the presence of the control devices and indicators bearing the references 32 to 46, already described with reference to FIG. 1, is noted. It is noted however that the elements 32, 42 and 46 are connected to four wires leading to a connector 48, and that the elements 34 to 40 and 44 are connected to another connector 50. The wires 14 shown in FIG. 1, two in number, each represent a group of wires connected to each of the connectors 48 and 50. The connectors 48 and 50 provide the connection to corresponding connectors 48 'and 50' shown in FIG. 2.

 Figure 2 shows in detail most of the elements contained in the body 10 of the charger. Note in FIG. 2 that the body 10 is represented by the continuous rectangle which surrounds all of the circuits. It is also noted that the body 10 is divided, by the dashed line 52, into a part 54 comprising most of the electronic circuits, preferably placed on the same card, and a part 56 "of power".

 More specifically, the power part 56 includes the elements through which most of the charger's energy passes. This part 56 consists of elements separated from the electronic card. These elements successively include a transformer T1 which receives alternating current at 220 V, regulated by the regulator described below, the rectifier PTD1, formed by a diode bridge and which transmits a unidirectional current, two diodes D21, D22 placed in downstream of a branch point and two power outputs BAT1 and BAT2 corresponding to terminals 18 and 20. In addition, a terminal BAT, corresponding to terminal 22 in Figure 1, is intended to be connected to the negative poles of the groups of storage batteries.

 According to a first characteristic of the invention, the power regulation of the charger is carried out by regulation of the input voltage. More precisely, as indicated in FIG. 3a, the alternating voltage at 220 V, transmitted by the fuse 46 and the switch 22, arrives via the connectors 48, 48 ′ at a first end of the primary of the transformer T1 and at a contact REL relay which, in the rest position shown, ensures the connection with another terminal of the connector 48 ', 48; the indicator 42 then indicates a fault, because the transformer T1 is not energized. As described below, the operation of the regulator causes the REL relay contacts to move to the other position so that the other 220 V supply wire is connected to the other terminal of the transformer T1 primary by the intermediate of thyristor THl. This allows the regulation of the charger, and it is controlled for this purpose by the regulator, via an optocoupler OPT1. In the event of failure of thyristor TH1, the high alternating voltage cannot therefore be transmitted to the rest of the circuit.

 Furthermore, it is noted that, as soon as a voltage is transmitted via the switch 32, another circuit is energized. This includes the transformer T2 and the rectifier PTD2, constituting a power supply for the electronic part 54. It should be noted that the current of this power supply is transmitted via a fuse F2 and a thermocontact THM1, for example a bimetallic strip. Thus, when the temperature of the thermal switch becomes too high, it causes the charger to stop operating, by controlling the coil of the REL relay and switching on the contact of the REL relay in the position shown in solid lines in FIG. 2.

 The only other element of the electronic part 54 of FIG. 2 which consumes alternating current at 220 V is a fan V1 which is supplied by a regulation comprising a thyristor TH2 controlled by means of an optocoupler OPT2. In this way, the other elements of the electronic part 54 cannot receive alternating current at 220 V, but only the current supplied by the power supply comprising the transformer T2 and the rectifier PTD2.

 It is noted that the unidirectional current transmission wires, between the diodes D21, D22 and the output terminals 20, 18 respectively, are connected, by means of switches SW1, to the rest of the electronic part. These circuits constitute voltage taps allowing the implementation of the regulation program.

However, as indicated by the switches SW1, in the position opposite to that shown in FIG. 2, the three switches SW1 ensure the connection to the terminals RBAT1, RBAT2 and RMASS which are none other than the terminals 28 indicated in the figure 1. Consequently, when wires are effectively placed between the terminals 28 and the terminals of the battery groups 24, 26, the switches SW1 are set in the position opposite to that which is shown in FIG. 2. However, when the wires of connection between the terminals 18, 20, 22 and the storage batteries 24, 26 have a short length, the voltage drop is low and it suffices to use the normal circuit, the switches SW1 being in the position indicated on the figure 2. A REL3 relay only allows the reading of the battery voltages when there is actually a current in the circuit. On the other hand, a REL2 relay selects the group of batteries whose voltage is measured for regulation.

 We now consider the operation of the charger according to the invention, in the embodiment described above.

 It is assumed that the charger is not in circuit, that is to say that the switch 32 is open. We begin by closing the switch 32. The alternating current at 220 V is then transmitted and it passes directly through the contact of the relay REL and causes the instantaneous warning light 42 on the control unit to come on. However, the alternating current is also transmitted to the power supply of the electronic part, that is to say to the transformer T2 and to the rectifier PTD2. Consequently, the regulator is energized and it causes the REL relay winding to be powered so that the REL relay contact changes position and causes the main circuit, i.e. the transformer TI to be powered by the intermediary of thyristor TH1. The fault lamp AL1 or indicator 42 therefore only lights up for a very short time when the power is turned on. It is assumed that the group of batteries having the lowest voltage is at a voltage below 14.4 V.

The regulator therefore determines that the batteries must be charged and begins regulation by controlling the thyristor TH1, according to the value of the constant current determined by the potentiometer P3, identified by the reference 34 in FIGS. 1 and 3b. The intensity of the current is indicated by the ammeter 36. The user then adjusts the knob of the potentiometer 34 in order to determine the charge intensity for example, this intensity has a value which, expressed in amperes, is equal to one tenth of the value representing the capacity, expressed in ampere-hours. At this time, the charger operates by ensuring the charging of the batteries so that the indicator 38 of green color is permanently on and the indicator 40 of red color is off.

 When the regulator determines that the voltage of the group of batteries having the lowest voltage is equal to 14.4 V, it interrupts the charging at constant current and goes into an equalization phase at constant voltage of 14.4 V, the current maximum being that which is fixed by the potentiometer. This equalization phase, which begins when the batteries are approximately 4/5 charged, lasts for example three hours. During this phase, the green light 38 flashes, the light 40 is always off.

 When the equalization phase is complete, the green light 38 goes out and the red light 40 lights up, indicating that the charger is in the standby state.

 During all these operations, the warning light 42 remained off.

 When the voltage of a battery group drops to 11.9 V, the charger automatically resumes charging, and the indicator 38 lights up continuously and the indicator light 40 goes out.

The operation continues as before, with an equalization phase.

 It may happen, for example a little before the boat leaves the dock, that the user wishes to charge the batteries to the maximum, although the most discharged group is still at a voltage greater than 11.9 V. At this time, the user presses the push-button contact 44, so that he restarts the operation of the charger as if it had just been switched on, the charger then ensuring the charge as indicated previously. In this way, it is possible to fully recharge the storage batteries even when they are not fully discharged, first at constant current, then at constant voltage.

 The operations just described are those of normal operation. However, the charger has several safety features to resolve the problems posed by a failure of the batteries or the charger. First, if the voltage of a battery group 24, 26 exceeds 15.6 V before the other battery group reaches 14.4 V, the regulator detects this overvoltage across the terminals of a battery group and interrupts the supply of the REL relay coil, so that the REL relay contact returns to the position shown in solid lines in FIG. 1, interrupting the operation of the charger and causing the warning light 42 to come on. which is directly supplied by the alternating voltage at 220 V, is for example a neon indicator.

According to another safety characteristic, the charger provides protection against short-circuits of the battery. Indeed, if the voltage across a battery group, measured directly or via terminals 18 to 22, falls below 4 V, the regulator interrupts the supply of the REL relay winding and therefore causes switching on this relay
REL in the position shown in FIG. 1 and the lighting of the warning lamp 42 indicating a fault.

 According to another safety characteristic, if a group of batteries is disconnected from the charger, the voltage detected at the terminals of this group is no longer between 4 and 15.6 V, and the regulator interrupts the supply of the REL relay winding. and consequently causes the warning light 42 to come on.

 According to another safety characteristic, when the temperature of the charger exceeds 95 "C, the THM1 thermal switch opens the regulator supply circuit, so that it interrupts the supply of the REL relay winding and therefore causes the ignition of witness 42.

When the temperature of the charger has dropped to 60 C, the THM1 thermoswitch automatically puts the charger back into operation by feeding the REL relay winding.

Consequently, the fault indicator 42 goes out.

 According to another safety characteristic, in the event of a power supply failure in the electronic part 54, the regulator can no longer ensure the supply of the winding of the relay REL, so that it interrupts the supply of the transformer T1 and causes l ignition of the fault lamp 42.

 Finally, according to another safety characteristic, if the part of the regulator which interrupts the charging operation when the voltage of the least charged battery group reaches 14.4 V no longer functions, the part of the regulator which ensures the interruption of the supply of the REL relay winding when the voltage of any battery group reaches 15.6 V continues to operate and therefore causes the charger to stop operating and the fault lamp to light up.

 The origin of most of the above-mentioned incidents is to be found in the storage batteries, either that these are in open circuit, or that they are in short circuit, or that they are badly connected. Consequently, if, after sufficient time for a suitable temperature reduction, the charger is not in operation again, the batteries and their connections should be checked.

 Although the invention has been described with reference to a charger for pleasure craft, it also applies to all cases posing similar problems, for example when it is desirable that control devices and / or indicators are placed away from the batteries.

Claims (10)

 1. Charger for accumulator batteries, of the type which comprises an alternating current input (16), a transformer (T1) intended to receive the alternating current coming from the entry, a rectifier (PTD1) intended to receive alternating current of the transformer and to form a unidirectional current, an output (18, 20) of the unidirectional current of the rectifier, a regulator of the charger operation, at least one control device and at least one indicating device, characterized in that  the regulator is arranged between the input (16) and the transformer (T1),  the transformer (T1), the rectifier (PTD1) and the unidirectional current output are at a first location, and  the at least one control device (32, 34, 44) and at least one indicating device (38 to 42) are at a second location remote from the first.  2. Charger according to claim 1, characterized in that the current input (16) is in the second location, and the voltage regulator is in the first location.  3. Charger according to one of claims 1 and 2, characterized in that it comprises at least one fuse (46) mounted between the input and the transformer and arranged in the second location.  4. Charger according to any one of the preceding claims, characterized in that the first location is very close to the storage batteries (24, 26) which must be charged by the charger, and the second location is close to a station control or navigation.  5. Charger according to any one of the preceding claims, characterized in that the control device comprises at least one device chosen from a power control switch (32), a potentiometer (34) for controlling the regulator, and a reset switch (44), and the indicating device comprises at least one indicating device chosen from an ammeter (36) giving the intensity of the unidirectional current, a charge indicator (38), a standby indicator (40) and a fault indicator (42).  6. Charger according to any one of the preceding claims, characterized in that the charger is intended to charge at least two batteries or groups of batteries (24, 26), and it is characterized in that it has a number of outputs (18, 20) of unidirectional current equal to the number of batteries or groups of batteries, each output being connected by a diode (D21, D22) at the output of the rectifier, and in that, after charging at constant current, the regulator ensures equalization at constant voltage of the batteries.  7. Charger according to any one of the preceding claims, characterized in that the regulator is intended to ensure charging until the voltage at the terminals of the battery, of the battery group, of each battery or of each group of batteries rises to a high value, then to ensure a new charge when the voltage at the terminals of the battery, of the battery group, of each battery or of each group of batteries has dropped to a reduced value.  8. Charger according to claim 7, characterized in that the regulator is intended to interrupt the charging when the voltage at the terminals of the battery, of the battery group, of a battery or of a battery group exceeds a cut-off value high which is greater than said high value, and it is intended to interrupt the charge when the voltage across the terminals of the battery, of the battery group, of at least one battery or of at least one group of batteries falls below a low cutoff value which is less than said reduced value.  9. Charger according to any one of the preceding claims, characterized in that it comprises a thermosensitive device (THM1) of safety intended to interrupt the unidirectional current when the temperature of a part of the charger reaches a predetermined value, and to cause resumption of unidirectional current transmission when the detected temperature reaches a second temperature lower than the first.  10. Charger according to any one of the preceding claims, characterized in that it comprises a safety device (REL) intended to interrupt the supply to the charger in the event of a -regulator supply fault, and a device for safety independent of the regulator and intended to provide protection against voltage overloads.