JPH0683548B2 - Auxiliary storage battery charger - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a charging method for a storage battery, and particularly to a charging device for an auxiliary storage battery that smoothly charges an auxiliary storage battery in an automobile or the like.

[Conventional technology]

In the conventional charging method, the following method has been known as a method for smoothly charging a main storage battery of an automobile and an auxiliary storage battery for recreation such as a camping car or for emergency such as a ship.

First, in JP-A-51-130833, a part of the output of the generator is half-wave rectified to charge the auxiliary storage battery. This method has a drawback that the generator has a special specification.

Further, as an example using a standard generator, Japanese Patent Laid-Open No. 56-1
No. 01343 and U.S. Pat. No. 3,806,709 are included.

In any case, the above-mentioned conventional technique is one in which wiring is further added to the auxiliary storage battery for charging.

[Problems to be solved by the invention]

The purpose of use of the above-mentioned auxiliary storage battery is for recreation or emergency use, and in many cases, a user of a vehicle optionally mounts an auxiliary storage battery other than the onboard storage battery. In automobiles, the main storage battery is usually installed in the engine room near the generator, but the auxiliary storage battery is installed in the trunk room (luggage compartment) where users can remove and move it. Often mounted. In addition, due to advances in storage battery manufacturing technology, for example, JP-A-60
-Since it is now possible to commercialize the sealed storage battery disclosed in Japanese Patent No. 1753, etc., and there is no need to worry about electrolyte leakage, etc., there is a growing demand for installation in the trunk room. Natsuta. However, in the above three conventional methods, it is necessary to wire the charging line of the auxiliary storage battery from the engine room to the trunk room, and it is difficult for the user to install a new auxiliary storage battery. There was a problem.

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a charging device for an auxiliary storage battery capable of charging an auxiliary battery installed in a trunk room with simple wiring.

[Means for solving problems]

The above object is achieved by using, as a charging line, a wire for supplying electric power from a power source in the engine room to a brake lamp in the trunk room via a brake switch in the vehicle compartment. It is also necessary to provide safety by providing a current limiting circuit for preventing the wiring from burning out when the charging current becomes excessive when the wiring of the brake / lamp is used as the charging line.

[Action]

The brake switch is closed in conjunction with a brake pedal that the driver of the vehicle depresses when reducing the traveling speed. When the brake switch is closed, the voltage from the main storage battery or generator is applied to the brake lamp. At this time, the auxiliary storage battery is charged at the same time.

The charging current value of the storage battery may increase depending on the charging state, temperature, etc., and an excessive current may flow.In such a case, the charging current is detected and charging is performed so that the current value does not exceed a certain value. Control. As described above, the wiring of the brake lamp is used to charge the auxiliary storage battery and to prevent the wiring from being burnt out.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. First
The figure shows a power supply circuit of a three-box type automobile. Reference numeral 1 denotes an engine room, which includes a generator 10 driven by an engine (not shown) to generate DC power, a main storage battery 11 charged by the generator 10 and supplying power to various loads. A vehicle compartment 2 has a load 22 supplied with power from the main storage battery 11 via a switch 21, a brake lamp switch 23 closed by depressing a brake pedal, and the like. 3 is the trunk room, brake lights
It has 31a, 31b, an auxiliary storage battery 32, and a controller 33.

FIG. 2 is an internal circuit diagram of the controller 33 of FIG.
It is composed of a P-channel type power MOS-FET 101, a resistor 102 for current detection, a PNP-type transistor 103, resistors 104, 105 and a diode 106.

In the above structure, the main storage battery 11 is charged from the generator 10 when the engine is rotating. When the driver steps on the brake pedal when reducing the speed of the vehicle, the brake lamp switch 23 is closed in conjunction with it,
A voltage is applied to the brake lamps (31a, 31b) to light them. Vehicles that run on the road, such as automobiles, usually have brake lamps 31a and 31b at the rear part to prevent a rear-end collision. When the brake lamps 31a and 31b are turned on, a voltage is generated at the a terminal of the controller 33. In FIG. 2, when the current flowing through the resistor 102 is small, the transistor 103 is off, the gate of the power MOS-FET 101 falls to the ground potential, the source and drain are conducted, and the diode 106 is passed through the auxiliary storage battery. Charging current flows to 32.
Further, when the brake lamp switch 23 is open, the power supply path to the auxiliary storage battery 32 is cut off, and the discharge current does not flow from the auxiliary storage battery 32 due to the function of the diode 106.

On the other hand, when the state of charge of the auxiliary storage battery 32 is not good, or when it is left for a long time, a transient charging current as shown in FIG. Normally, the brake lamps 31a and 31b are designed so that a current of about 25w × 2 / 12V = 4A flows through the wiring for using a light bulb of about 25w. However, when a storage battery is connected as a load as in the present invention, such an excessive current may flow and the wiring may be burnt out. Therefore, in this embodiment, a current limiting mechanism is provided. When an overcurrent flows through the resistor 102, a voltage is generated across the transistor 102 and the transistor 103 is turned on. Then, the gate potential of the power MOS • FET 101 becomes high, the source-drain is cut off, and the current stops flowing. Actually, when the conductivity of the power MOS-FET 101 decreases, the current value decreases, and when the current value decreases, the transistor 103 turns off and the conductivity of the power MOS-FET 101 increases, so negative current is applied. Is controlled to a constant value. Therefore, the charging current to the auxiliary storage battery 32 is such that the maximum current value is suppressed as shown in FIG. 3b.

According to this embodiment, by adding a simple circuit to the wiring of the conventional automobile, the auxiliary storage battery 32 can be charged, and further, since the charging current value can be limited, it is possible to prevent the wiring from being burned. it can. Also, power MO as a power element
Since S-FET 101 is used, it is possible to reduce the voltage drop by selecting a low on-resistance.

A second embodiment of the present invention will be described with reference to FIG. FIG. 4 shows another embodiment of the controller 33 in FIG. The external circuit of the controller 33 is similar to that shown in FIG. In FIG. 4, 201 is a PNP type power transistor, 102 is a resistor for current detection, 103 is a PNP type transistor 104,
105 is a resistor. Further, 202a and 202b are voltage divider resistors, 2
03 is a Zener diode and 204 is an NPN transistor. In this configuration, first, the operating voltage of the voltage detection circuit including the voltage dividing resistors 202a and 202b and the Zener diode 203 is set to, for example, 13.5V, which is the voltage when the storage battery is in the charging state. Brake / lamp / switch
When 23 is open, the voltage of the auxiliary storage battery 32 is low, so that no current flows through the transistor 204 and the base current of the power transistor 201 does not flow, so the circuit does not operate and the auxiliary storage battery 32 does not discharge. Next, the brake lamp switch 23 is closed and a voltage is applied to the a terminal,
When the voltage is sufficiently high, the transistor 204 becomes conductive through the voltage dividing resistors 202a, 202b and the Zener diode 203,
A base current flows from the a terminal through the resistor 102, the emitter of the power transistor 201, the base, and the low resistance device 105,
Power transistor 201 conducts. Then, the voltage is applied to the auxiliary storage battery 32 via the terminal b, and the charging current is supplied. As in the first embodiment, when the charging current value becomes excessive, the voltage across the resistor 102 increases, the base current of the transistor 103 flows, and the transistor 103 becomes conductive. The flowing current limits it.

On the other hand, when the electric load 22 connected in parallel with the main storage battery 11 is overloaded, or when the generator 10 is not generating power, the voltage applied to the a terminal of the controller 33 is low. , Voltage divider resistors 202a, 202b, Zener diode 20
Since the voltage detection level of the voltage detection circuit by 3 is not reached and the transistor 204 is cut off, the power transistor 2
Since the base current of 01 is not supplied, the power transistor 201 is cut off, and the auxiliary storage battery 32 is not charged or discharged from the auxiliary storage battery 32 to the external load.

According to this embodiment, the diode 106 in the first embodiment is
Is unnecessary, and the advantage is that it is not necessary to consider the decrease of the charging voltage of the auxiliary storage battery 32 due to the voltage drop of the diode 106. Further, when the charge state of the main storage battery 11 is good and the charge state of the auxiliary storage battery 32 is bad, the charge stored in the main storage battery 11 is stored in the auxiliary storage battery 32 even though the generator 10 is stopped. It is possible to solve the problem that the main storage battery 11 is deteriorated in charge state by moving to.

Next, a third embodiment of the present invention will be described with reference to FIG. In the first and second embodiments, the charging voltage of the auxiliary storage battery 32 is affected by the output voltage of the generator 10, but in the present embodiment, the DC-DC converter is used to output a constant voltage. , To ensure a constant charging voltage. FIG. 5 shows another embodiment of the controller 33 of FIG. The external circuit of the controller 33 is similar to that shown in FIG. In FIG. 5, 301 is N
It is a PN type power transistor, and 302 is a coil having an iron core. Resistor 102, 104, PNP type transistor 103
Constitutes a current limiting circuit, and performs the same function as the second. 30
3 is a resistor, 304 is an oscillation circuit that outputs a rectangular wave, 305 is a 3-input NOR gate, 306 is a diode,
307a and 307b are voltage divider resistors.

In this configuration, when the brake / lamp switch 23 is turned on, a voltage is generated at the a terminal of the controller 33.
Then, the oscillator circuit 304 operates and gives an ON / OFF signal to the power transistor 301 via the NOR gate 305.
When the current of the coil 302 is cut off by the power transistor 301, flyback and voltage are generated at both ends of the coil 302, and the current flows through the diode 306 to the auxiliary storage battery 32. The voltage dividing resistors 307a and 307b detect the voltage of the auxiliary storage battery 32, and when the voltage becomes high, the voltage at the voltage dividing point becomes NO.
R Gate 305 input threshold level exceeded and NOR
The output of the gate 305 becomes "0" level. Then, the oscillation signal is not transmitted to the power transistor 301, the flyback voltage is not generated in the coil 302, and the charging of the auxiliary storage battery 32 is stopped. When the charging of the auxiliary storage battery 32 is stopped, the voltage drops and the voltage dividing resistors 307a, 3
The voltage at the voltage dividing point of 07b becomes lower than the input threshold level of the NOR gate 305, and the oscillation signal is transmitted to the power transistor 301 again, so that the flyback voltage is generated in the coil 302 and the auxiliary storage battery is generated via the diode 306. 32
Charge and increase its voltage. As described above, the voltage across the auxiliary storage battery 32 is controlled to a constant value. Also, as in the first and second embodiments, when the current flowing through the resistor 102 becomes excessive, the transistor 103 becomes conductive, the output of the NOR gate 305 is set to "0" level, and the transistor 301 oscillates. Since it operates so as not to give a signal, the current value is limited.

In the present embodiment, since the galvanic voltage of the auxiliary storage battery 32 is controlled to be a constant value, the brake lamps 31a, 31b from the generator 10 are controlled.
Good charging is performed even when the wiring resistance to the wiring is large.

〔The invention's effect〕

According to the present invention, it is possible to smoothly charge the auxiliary storage battery that is located apart from the main storage battery, that is, the auxiliary storage battery in the trunk room, by simple wiring, so that the performance of the main storage battery deteriorates and insufficient charging occurs in cold regions. When a start failure occurs due to, for example, the auxiliary storage battery used for emergency can always be kept in a good charge state, and safety is enhanced.

As a power supply device for recreation such as cleaning, the auxiliary storage battery can be stored in a place such as a trunk room where it can be easily stored and taken out, which is convenient.

There is an effect. Further, in the present invention, since charging to the auxiliary storage battery is mainly performed at the time of braking, it is possible to store, in the auxiliary storage battery, charge energy that was conventionally consumed as heat generated in the brake device among kinetic energy of the vehicle. Therefore, even if the auxiliary storage battery is attached, extra energy is not required, and the energy can be effectively used.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a power supply system of an automobile according to an embodiment of the present invention. 2 is an internal circuit diagram of the controller 33 of FIG. 1, FIG. 3 is a waveform diagram for explaining the operation of the circuit of FIG. 2, and FIG. 4 is a circuit of the second embodiment of the controller 33 of FIG. 5 and 5 are circuit diagrams of a third embodiment of the controller 33 shown in FIG. 1 ... Engine room, 2 ... Vehicle room, 3 ... Trunk room, 10 ... Generator, 11 ... Main storage battery, 23 ... Brake lamp switch, 31a, b ... Brake lamp, 32 ... auxiliary storage battery, 33 ... controller.

Claims (3)

[Claims] 1. A vehicle generator, a main storage battery charged by the generator, a brake lamp switch closed during a braking operation of the vehicle, and the main storage battery including the brake lamp switch. In a vehicle power supply device including a brake lamp connected via a brake lamp, an emergency auxiliary storage battery that is charge-controlled via a control when the brake lamp switch is closed is provided in parallel with the brake lamp. A charging device for an auxiliary storage battery, which is provided and installed at a position distant from the main battery. 2. A current detection circuit and a power element are provided between the brake lamp and the auxiliary storage battery according to claim 1, and the current value detected by the current detection circuit is a certain value or more. In this case, the auxiliary storage battery charging device is characterized in that a current limiting circuit that cuts off the power element and limits a current value charged in the auxiliary storage battery is formed. 3. A boosting means is provided between the brake lamp and the auxiliary storage battery according to claim 1,
A charging device for an auxiliary storage battery, wherein the charging voltage of the auxiliary storage battery is increased.