JPH07277108A - Battery checker - Google Patents

Abstract

PURPOSE:To provide a battery checker which precisely measures capacity of a battery and gives an alarm. CONSTITUTION:When an engine of a vehicle is stopped, a check signal outputting circuit 50 outputs a check signal for the fixed duration. While the check signal is generated, a current deriving circuit 56 derives heavy-current from a battery. In this process, an alarm signal outputting circuit 66 determines whether the output voltage of the battery is lowered below a normal level or not for outputting an alarm signal. An alarm indicating circuit 88 gives an alarm in response to the alarm signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery checker for informing a user of whether or not an engine can be started by detecting deterioration of the capacity of a vehicle-mounted battery.

[0002]

2. Description of the Related Art A conventional battery checker measures only the output voltage of a battery and displays it by using an LED or a needle type meter.

That is, as shown in FIG. 3, a battery checker using an LED includes a plurality of constant voltage circuits 2 and 4 composed of resistors and zener diodes, and a plurality of resistors 6 and 8 connected in series to a battery. , A plurality of comparators 10 and 12 for comparing the voltage between the resistors 6 and 8 with the voltages set by the constant voltage circuits 2 and 4, respectively, and a plurality of display circuits 1 each including an LED that lights up when its output signal is input.
It consisted of 4, 16 and so on. In this battery checker, the lighting state of the display circuits 14 and 16 changes as the output voltage of the battery decreases, thereby informing the user of the voltage decrease.

Further, as shown in FIG. 4, a battery checker using a needle type meter takes out a predetermined voltage from between the resistors 18 and 20 directly connected to the battery as an output voltage of the battery and outputs it as an amplifier circuit. After being amplified at 22, the voltage was applied to the meter 24 to display the level of the voltage.

[0005]

Generally, the capacity of a battery is judged to be good if it actually consumes current and the voltage drop at that time is small. However, in the above conventional example, since the output voltage of the battery is measured in a state irrelevant to the current, there is a problem that the true battery capacity cannot be known. Especially when the output voltage is measured with a conventional battery checker when the engine and electrical parts are in a stopped state and no current flows from the battery, it is displayed higher than the true battery capacity, and there is no problem in starting the engine. I made the wrong decision.

The present invention has been made in view of the above problems, and an object thereof is to provide a battery checker for more accurately measuring the capacity of a battery and issuing an alarm.

[0007]

The battery checker of the present invention is a check signal output circuit for outputting a check signal for a certain period of time when the vehicle engine is stopped, and a large current is drawn from the battery while the check signal is generated. A current drawing circuit, an alarm signal output circuit that outputs an alarm signal when the output voltage of the battery drops below a specified level due to a voltage drop when the current drawing circuit draws a large current from the battery, and in response to the warning signal. And an alarm circuit for alarming a decrease in battery capacity.

[0008]

In the battery checker of the present invention, when the vehicle engine stops, the check signal output circuit outputs a check signal for a certain period of time, and the current drawing circuit draws a large current from the battery only while the check signal is generated. . The alarm signal output circuit determines whether or not the output voltage of the battery has dropped below a specified level due to the voltage drop at this time, and outputs an alarm signal if the output voltage has dropped below the specified level, thereby issuing an alarm. As described above, in the present invention, a large amount of current is drawn from the battery in order to check the capacity of the battery, so that the user can be accurately notified of the state of the battery.

[0009]

1 is a circuit diagram showing the configuration of a battery checker according to an embodiment of the present invention. 26 is a power supply line connected to the input terminal BAT connected to the battery, 28 is a power supply line used to draw a large current when measuring the battery capacity, and 30 is a measurement power supply line connected to the input terminal BAT. An accessory power supply line connected to the input terminal ACC that is brought into a non-conducting state when the engine is stopped, the engine key is turned off, or the power supply to the electrical component is stopped, and the input terminal GN is connected to the ground.
It is a ground connection line for grounding D.

Reference numeral 34 is a power supply stabilizing circuit for supplying a predetermined electric power to each circuit to be described later, so that the resistor 36 connected in series to the power supply line 26 and the power supply line 26 and the ground are in parallel with each other. Zener diode 3 connected to
8 and a condenser 40.

Reference numeral 42 denotes a stabilizing circuit for stabilizing the signal from the input terminal ACC, which is connected in parallel with the resistor 44 connected in series to the accessory power supply line 30 and between the accessory power supply line 30 and the ground. It is composed of a Zener diode 46 and a resistor 48 which are connected to each other.

Reference numeral 50 is a check signal output circuit which outputs a check signal for a certain time when a signal A indicating the stop of the engine or the like input through the stabilizing circuit 42 is input. The check signal output circuit 50 has a one-shot circuit 52 which inputs the signal A to the input B and outputs one pulse having a pulse width of T1 seconds in synchronization with the falling edge, and a pulse from the output Q to the input B. The one-shot circuit 54 which inputs and outputs the check signal B consisting of one pulse having a pulse width of T2 seconds in synchronization with the fall.

Reference numeral 56 is a current drawing circuit for drawing a large current from the battery while the check signal B is being generated. The current drawing circuit 56 is provided between the resistor 58 and the measuring power supply line 28, and a resistor 58 having a small resistance value of several ohms, which is connected to the battery via the measuring power supply line 28 at the time of drawing the current. A relay switch 60 that is provided to connect and disconnect the resistor 58 and the battery, and a collector and an emitter are connected to the coil and ground of the relay switch 60, respectively, and the one-shot circuit 5 is connected via the resistor 64.
The output Q of 4 is composed of a transistor 62 for switching the state of the relay switch 60 connected to the base.

Reference numeral 66 is an alarm signal output circuit for judging the battery capacity when a large current is drawn from the battery from the state of the voltage drop. This alarm signal output circuit 6
Reference numeral 6 supplies a backflow preventing diode 68 connected to the measurement power supply line 28, a voltage adjusting resistor 70 connected in series to the diode 68, and a constant voltage connected between the resistor 70 and the ground. Zener diode 72 for smoothing, smoothing capacitor 74 connected in parallel therewith, (−) terminal is connected to the battery via measurement power supply line 28, and resistor 70, Zener diode 72 and capacitor are connected. And a comparator 76 for inputting a voltage signal of a specified level supplied to the (+) terminal to the alarm signal C and outputting the alarm signal C.

Reference numeral 78 is a latch circuit composed of a flip-flop, which inputs the alarm signal C to the clock input CK and also inputs the signal A from the input terminal ACC to the reset input R, which is synchronized with the rising edge of the alarm signal C. The output Q to H level.

Reference numeral 80 is a timer circuit which operates in response to a signal from the latch circuit 78 for a fixed time.
A first timer 82 which outputs an H level signal for a certain time when a signal from 8 is input, and a second timer 84 which repeats counting at an interval shorter than the first timer 82 when a signal from a latch circuit 78 is input, and And an AND gate 86 for inputting the output signal of.

Reference numeral 88 is an alarm display circuit, which is composed of an LED 92 that lights up when a signal from the timer circuit 80 is input through the resistor 90.

In this embodiment, the latch circuit 7
8. The timer circuit 80 and the alarm display circuit 88 constitute an alarm circuit for alarming the deterioration of the battery capacity.
Further, this alarm circuit is the LED 92 in this embodiment.
In addition to the above, the sounding circuit may be used instead of the warning display circuit 88 to emit a warning sound.

Next, the operation of the battery checker having the above structure will be described with reference to the time chart shown in FIG. First, when the vehicle engine is stopped and the signal A from the input terminal ACC becomes L level, the one-shot circuit 52 outputs a pulse in synchronization with the fall of the signal A. Then, the one-shot circuit 54, which receives the pulse, outputs the check signal B consisting of one pulse in synchronization with the fall. When a pulse is generated in the check signal B and becomes H level, the check signal B
During the T2 seconds when H is at the H level, the transistor 62 is in the conductive state and the relay switch 60 is excited to be in the ON state. As a result, the resistor 58 is connected to the battery via the relay switch 60, and a large current flowing through the resistor 58 is extracted from the battery. At this time, if the capacity of the battery is insufficient, the voltage drop of the battery when a large current is drawn becomes large. When the voltage drop is large like this, the comparator 76 comparing the voltage of the specified level input to the (+) terminal with the output voltage of the battery input to the (-) terminal has the output voltage of the battery lower than the specified level. Then, the alarm signal C is set to H level. The latch circuit 78 latches the alarm signal C and holds its output Q at H level, and in response to this, the first and second timers 82 and 84 operate. The signals D and E output from the first and second timers 82 and 84 are combined by the AND gate 86 and applied to the LED 92 as a clock generated for a fixed time. As a result, the LED 92 blinks for a certain period of time to indicate that the battery capacity is low.

If the battery has a high capacity and the voltage drop is relatively small even if a large current is drawn, the output voltage of the battery will not fall below the specified level. Therefore, in this case, the alarm signal output from the comparator 76 is maintained at the L level and no alarm is issued.

When the check signal B becomes L level after T2 seconds, the transistor 62 becomes non-conductive and the relay switch 60 also becomes off. When the relay switch 60 is thus turned off, the drawing of a large current from the battery is stopped, the output voltage of the battery rises, and the alarm signal C output by the comparator 76 becomes L level. When the signal A becomes H level due to the engine key being turned on or the like, the latch circuit 78 is reset and returns to the initial state.

Considering that the battery capacity is decreasing, the large current for checking is set to be drawn for a short time such as several seconds, and the alarm is fixed by using a timer circuit or the like. It is set to operate only for hours.

[0023]

According to the present invention, the capacity of the battery is measured by turning off the engine and drawing a large amount of current for checking. Therefore, the true capacity of the battery is accurately inspected and an alarm is given to the user. can do.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a battery checker according to an embodiment of the present invention.

FIG. 2 is a time chart of main signals shown in FIG.

FIG. 3 is a circuit diagram showing a configuration of a conventional battery checker.

FIG. 4 is a circuit diagram showing a configuration of a conventional battery checker.

[Explanation of symbols]

 50 Check signal output circuit 56 Current extraction circuit 66 Alarm signal output circuit 78 Latch circuit 80 Timer circuit 88 Alarm display circuit

Claims (1)

[Claims] 1. A check signal output circuit for outputting a check signal for a certain period of time when a vehicle engine stops, a current drawing circuit for drawing a large current from a battery while the check signal is generated, and the current drawing circuit is a battery. An alarm signal output circuit that outputs an alarm signal when the output voltage of the battery drops below a specified level due to a voltage drop when a large current is drawn from the alarm circuit; and an alarm circuit that warns of a decrease in battery capacity in response to the alarm signal. Battery checker characterized by consisting of.