In this project, we will learn how to build a simple DIY lithium battery charger using a USB cable. This charger is designed to safely charge a 3.7V lithium battery using a charging module. The project is beginner-friendly and requires only a few basic components.
Components Required
Charging Module - BUY NOW
USB Cable - BUY NOW
Lithium Battery (3.7V) - BUY NOW
Lithium Battery Holder - BUY NOW
Transparent Acrylic Sheet - BUY NOW
Jumper Wires - BUY NOW
Step 1: Understanding the Charging Module
The charging module is the core component of this project. It regulates voltage and current to safely charge the 3.7V lithium battery. The module typically features:
Micro USB Input: Connects to a USB power source.
Battery Terminals: For connecting the lithium battery.
LED Indicators: Indicate charging status (usually red for charging and green for fully charged).
Step 2: Preparing the USB Cable
Cut one end of a USB cable to expose the internal wires.
Identify the red (positive +) and black (negative -) wires, which provide power.
Strip the insulation off these wires to make proper connections.
Step 3: Connecting the Charging Module
Solder the red (+) wire from the USB cable to the IN+ terminal of the charging module.
Solder the black (-) wire from the USB cable to the IN- terminal of the charging module.
Step 4: Connecting the Lithium Battery
Insert the 3.7V lithium battery into the battery holder.
Connect the holder’s positive (+) terminal to the BAT+ pin on the charging module.
Connect the holder’s negative (-) terminal to the BAT- pin on the charging module.
Step 5: Securing the Setup
Mount all components onto a transparent acrylic sheet using double-sided tape or screws.
Arrange the wiring neatly to avoid short circuits and ensure safe operation.
Step 6: Testing the Charger
Plug the USB cable into a power source (such as a laptop or wall adapter).
Observe the LED indicators:
Red LED: Charging in progress.
Green LED: Battery is fully charged.
Check the voltage of the battery using a multimeter to verify proper charging.
