12v Battery Protection Circuit Used LM393 IC

[Sekhohub.online]

A 12V battery protection circuit using the LM393 comparator IC can help protect your battery from over-discharge (low voltage cutoff) and optionally overcharge. Below is a simple low-voltage disconnect circuit that cuts off the load when the battery voltage drops below a set threshold.

---

✅ Key Features

• Battery protection (disconnect load below 11V, for example)

• Uses LM393 dual comparator

• Controls a MOSFET or relay to disconnect the load

Materials for the Project.

1. 1X LM393 IC
2. 1X BC547 TRANSISTOR
3. 1X 5V ZENER DIODE
4. 2X 1N4007 DIODES
5. 2X 1K RESISTORS
6. 1X 4.7K RESISTOR
7. 1X 47K RESISTOR
8. 1X 10K TRIMPOT
9. 1X 12V RELAY
10. 2X 2-PIN TERMINAL BLOCKS
11. PERF BOARD
12. JUMPER WIRES

---

⚙️ Working Principle

• A voltage divider steps down the battery voltage to a level suitable for the comparator.

• The comparator compares the scaled voltage to a reference set by the potentiometer.

• When the battery drops below the set voltage (e.g., 11V), the comparator output changes and turns OFF the MOSFET or relay, disconnecting the load.

• ️ Optional Improvements

  • • Use a Zener diode (e.g., 5.1 V) for a more stable reference.

    • Add hysteresis with a feedback resistor to prevent rapid switching near the threshold.

    • ⚠️ Notes

      • LM393 has an open-collector output, so a pull-up resistor is necessary.

      • Choose a MOSFET that supports the current your load needs.

      • If you’re using a relay instead of a MOSFET, add a flyback diode across the relay coil.

 

---

---

Download Circuit Diagram

---