DIY TP4056 Battery Charger with 18650 Battery Level Indicator
If you are looking for a simple DIY battery charging circuit with a battery level indicator, then this project is perfect for you. Using the TP4056 battery charger module and a 3.7V 18650 Li-ion battery, we will build a compact and reliable battery charging and monitoring system. This project is highly useful for electronics hobbyists, students, and anyone interested in learning how to safely charge Li-ion batteries.
🔹 Components Required
Here is the shopping list for this project:
TP4056 Type-C Battery Charger Module with Protection
18650 Li-ion Battery (3.7V, 2000–2600mAh)
18650 Battery Holder
Battery Level Indicator Module (1S, 5 LED display)
Jumper Wires or Thin Electric Wires
Soldering Kit (optional, for permanent connections)
👉 All these components are easily available on Amazon, Flipkart, or local electronics shops.
🔹 Circuit Explanation
The TP4056 charger module is designed for charging single-cell Lithium-ion batteries (3.7V). It works with a 5V input supply (mobile charger/USB).
B+ / B- pins → Connect to the battery terminals
OUT+ / OUT- pins → Connect to the load (here, the battery level indicator)
Type-C/USB port → Connect to any 5V power adapter or mobile charger
The Battery Level Indicator module shows the real-time charge status of the battery using LEDs.
🔹 How It Works
Plug in mobile charger (5V) → TP4056 starts charging the 18650 battery.
Red LED ON (TP4056) → Battery is charging.
Blue LED ON (TP4056) → Battery is fully charged (around 4.2V).
The Battery Level Indicator shows charge percentage:
1 LED = 20% battery
3 LEDs = 60% battery
5 LEDs = 100% fully charged
👉 Note: After unplugging the charger, the indicator may show one bar less due to voltage drop. This is normal.
🔹 Applications
DIY power banks
Portable electronic devices
IoT projects
Educational projects for students
Backup power supplies
🔹 Cost & Selling Price
Component cost: ₹300–450 (depending on source)
You can sell a ready-made project for ₹800–1000
Great project idea for school/college students
🔹 Advantages of This Project
✅ Simple and low-cost design
✅ Uses easily available components
✅ Real-time battery monitoring
✅ Safe charging with protection circuit
✅ Can be extended for DIY power banks
🔹 Conclusion
This TP4056 battery charger project with 18650 battery and level indicator is a beginner-friendly DIY electronics project. It not only helps you learn about Li-ion battery charging circuits but also provides a practical solution for powering small devices. With just a few components, you can create your own battery charging and monitoring system at home.
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