12V Battery Level Indicator Circuit | 12V Battery Indicator
12v charging indicator circuit - Electronic Project
Introduction:
The circuit diagram of the battery voltage level indicator is shown in Fig. 3. It is built around the IC LM3914 dot/bar driver IC1, 1N4007 diodes D1 and D2, ten 5mm LEDs (LED1 through LED10), 12.1V Zener diode (ZD1), BC547 transistor T1, BC557 transistor T2, presets VR1 or VR2, or piezo buzzer PZ1. The LED display comprising LED1 through LED10 shows the voltage level of the 24V or 12V battery selected. This display could be set in dot mode or bar mode. To show the voltage level in the bar of the mode, connect pin 9 of the IC to the positive terminal of the battery using switch S2. To show the voltage level in dot mode, simply open the switch S2.
The circuit diagram can be used to check 24V and 12V batteries both. The battery level is indicated by the ten of the LEDs. Each glowing LED indicates 10% of the battery voltage level. So, when LED1 through LED5 are glowing, or just the LED5 is glowing, it means the battery is around 50% charged. The circuit diagram can help in checking the batteries for a car, inverter, solar system, etc.
This simple circuit diagram can be used to monitor whether a battery is charging or not. The voltage comparator IC LM393 is the heart of this circuit diagram. The LED D1 will remain ON whenever there is at least the 25 milli ampere current flowing to the battery. This particular circuit diagram is designed for a 12V battery with a charging current flow of less than 1A. By slightly modifying the component values, the charging current flow and voltage can be modified.
Diagram of 12V Battery Indicator:
Hardware Required for this Project:
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Working Principle of 12V Battery Status Indicator:
The 12v battery of the level indicator unit in the photo has no reverse polarity diode and R2 is the calibration potentiometer.D1 is the voltage of the reference zener. Tied to this is a string of dividers of the resistors (R2-6) that set the various fixed voltage levels. R7 & 8 form a voltage divider that reduces the battery of the voltage by a factor of 3. U1 is an LM339 quad comparator that compares the various of voltages from the two dividers. The comparator sections have open collector outputs that simply function as the switches to operate the LEDs. D7 protects against the reverse battery connection.
The LEDs are biased to operate at about 4mA which is quite bright if modern the LEDs are used. This current flow can be adjusted simply by varying the series resistors (R9 through R13). The overall current flow drain as shown is about 25mA which tends to be wasteful for continuous operation. For energy conservation, connect to the battery via a pushbutton (Push to Test).
The 12.1V Zener diode of the ZD1 is used along with BC547 transistor T1 to reduce the 24V battery voltage to 12V. Pin 3 of IC1 is connected to the positive side of 12V to operate the circuit diagram while pin 2 is connected to the ground. To check the voltage of the level of the battery, use two crocodile clips with about 30cm long wires soldered to each. One of the clips could be red with a red wire soldered to it or the other black with a black wire soldered to it. Connect the red clip to the positive of the battery under test and the black clip to its negative terminal. Flip of the switch S1 for checking a 24V battery’s status. The position of the switch S2 will depend on whether you want a dot display or a bar display.
Use presets VR1 and VR2 to calibrate the circuit diagram. And you may use a 30V of the variable power supply instead of the 24V battery for calibration. Connect 12V from the variable power supply in place of the 24V battery in the circuit diagram. Adjust preset VR1 such that the LED1 just starts glowing. Now increase the input DC of the voltage slowly to 24V and observe the LED’s glowing status. The first LED (LED1) will start glowing at 2.4V the second (LED2) at 4.8V, and so on. The last LED (LED10) will glow at 24V. After this calibration, the circuit diagram is ready to use. If you want to check the level of a 24V battery, connect it to the circuit diagram using the crocodile clips and flip switch S1 towards the 24V position.
To see the battery voltage level in bar mode, flip switch S1 towards the 24V position or turn switch S2 on. If, say, LED1 through LED9 starts glowing, it means the voltage level of the battery is around 90% of 24V, that is, around 21.6V. If all ten of the LEDs (LED1 through LED10) glow, it means the voltage level of the battery is full 24V.The buzzer in the circuit diagram sounds when the battery’s voltage level falls to 80% to indicate that the battery needs to be charged. The base of the transistor of the T2 connected to pin12 of IC1 drives the piezo buzzer.
Frequently Asked Questions
What is the 12V LED battery level indicator circuit?
We will make the indicator of the level in 4 stages. Here we can use four of the LEDs, 1 red, 1 blue, 1 green, and 1 yellow LED. Since the highest voltage will be around 12V, we need to use four 1kO resistors that we will connect for these of LEDs to work without damage.
What is a battery charge indicator?
a small direct-current flow ammeter that continuously indicates the net charging or discharging current flow of an automobile battery.
What is the importance of battery charging lights?
When this light is illuminated, the situation demands prompt attention. If the battery isn't being properly charged, it won't have enough power supply to start the engine or keep it running. This could result in a range of problems, from dim lights and weak ignition to a complete shutdown of the vehicle.
What are the three functions of the 12-volt charging system?
Name 3 functions of the charging of the system: - it supplies all vehicles with 12-volt electricity when the engine is running. - it provides a 13-15v output, which is slightly higher than a fully charged battery @12.6v. - it changes current flow and volume output to meet different electrical of loads.
How does a battery voltage indicator work?
The circuit diagram derives the power supply for its operation from the battery of the device itself. It uses ten of the LEDs wired in a 10-dot mode. The use of different colored LEDs makes it easier to recognize the voltage level on the basis of the calibration of the made.
