This article talks about a very useful and easy Battery Charger Circuit using IC L200 which helps battery work good and live long.
Furthermore, this circuit show reverse polarity using LEDs.
IC L200 is 5 pin voltage regulator which is very flexible and good for charging battery and also this IC have many features like current limit, heat shutdown and accurate voltage control; it is good choice for battery charging.
The 12V lead-acid battery circuit delivers stable voltage and current for safe, efficient charging.
Circuit Working:

Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | 1.8k | 1 |
| 820Ω | 1 | |
| 680Ω | 1 | |
| 56Ω | 1 | |
| 100Ω | 1 | |
| R2 (see the calculations below) | 3.9k | 1 |
| R3 (see the calculations below) | 470Ω | 1 |
| Preset Resistor 1k | 1 | |
| Capacitors | Ceramic 0.33µF | 1 |
| Electrolytic 1000µF 25V | 1 | |
| Semiconductors | IC L200 | 1 |
| NPN BC557 | 1 | |
| LED Red 5mm 20mA | 1 | |
| LED Green 5mm 20mA | 1 | |
| Diodes 1N4148 | 2 | |
| 1N5401 | 1 | |
| Meter FSD Meter 1.5A | 1 |
The above circuit diagram shows how battery charger work using IC L200, also circuit have parts like diode, resistor, capacitor, transistor and all help charge battery well.
L200 IC chip control voltage to battery and resistors R2 and R3 set voltage based on formula, then IC L200 also have current limiter inside which stops overcharging battery.
Now diode D1 1N4148 stop reverse current and keep circuit safe and diode D2 1N5401 stop battery discharge when circuit is OFF.
Also, the green LED1 turns ON when the battery is charging, and if the battery connects in reverse, the red LED2 glows due to transistor Q1 BC557.
Moreover, VR1 preset change the charging current and M1 meter protect from too much current.
Formulas:
Below are formula and example to make simple battery charger using IC L200:
Output Voltage Formula:
V_OUT = V_REF × (1 + R2 / R3) + (I_ADJ × R2)
where,
- V_REF is 2.77V inside L200
- I_ADJ is very small need to ignore
- R2 and R3 are resistors to set voltage
How to Build:
To build a Battery Charger Circuit using IC L200 follow below steps for connection:
- First, take all parts shown in circuit diagram.
- Next, connect pin 1 (INPUT) of IC L200 to one side of capacitor C2 and other side to GND and connect pin 1 also to +18V input and GND to negative and also connect capacitor C1 positive to pin 1 and negative to GND.
- Then connect pin 2 (LIMITING) to anode of diode D2 and cathode of D2 goes to positive of M1 meter and connect resistor R6 in parallel with D2.
- Now connect emitter of transistor Q1 to one end of R6, base of Q1 connect to other end of R6 through R7 and then collector of Q1 goes to positive of LED1 and then negative of LED1 goes to one end of R5 and then to GND.
- Also, between LED1 and R5 connect diode D3 anode and cathode of D3 goes to positive of LED2 and negative of LED2 to other end of R7.
- Then negative of M1 goes to middle pin of preset VR1, other leg of VR1 goes to pin 3 and pin 4 of IC.
- After that, pin 3 (GND) of IC goes to anode of diode D1 and cathode of D1 to GND and pin 4 (REF) connect to one side of R4 and other side of R4 go to GND.
- Finally, OUTPUT pin of IC connect to R2 and R3 in parallel and then connect +12V battery positive to M1 meter negative and battery negative to GND.
Conclusion:
To conclude, this Battery Charger Circuit using IC L200 show reverse polarity with LEDs, also it is safe for charging lead-acid and other rechargeable batteries.
Moreover, it features with current limit, overvoltage protect and LEDs for status, as this circuit is good for keeping battery healthy.
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