Introduction: Solar Powered Charger for 18650 Lithium Ion Cells

Charging Lithium Ion batteries is a tricky affair and too with solar power because Lithium-ion batteries are dangerous and require controlled charging environments. Otherwise, it may lead to explosion also. Here, I am going to build a 18650 Lithium-ion battery charger harnessing solar energy. Solar energy is abundant on earth surface. We will be using solar panels to convert solar radiation into electricity and use it to charge 18650 cells.

The setup can be used to power any electronic projects or devices such as projects which are installed in remote areas and it is uneconomical to power via other means. This setup can be used for an emergency purpose also if there is no power from the grid due to natural calamities such as flood etc.

Step 1: Get the Requirements

This project is made using cheap materials that can be sourced easily including Solar Panels, Lithium battery etc. The materials used in this project are as follows:

From Amazon:

Step 2: Connect the Battery to the TP4056 Protection Circuit

  1. Put the 18650 battery into the holder and solder wires across its connecting leads.
  2. Connect the +ve and -ve of the battery to the B+ pad and B- pad of the TP4056 circuit. TP4056 in a charger IC to charge 18650 batteries safely.
  3. The load can be connected to the OUT+ and OUT- of the circuit board.

Step 3: Charge the Battery Using Solar Power

TP4056 can be given charging power directly via micro USB but since we want it solar powered we have to add solar panels to it.

  1. Connect solar panels in parallel as much as you want. Here I am using 2.
  2. Connect the + and - from the solar panel to the IN+ and IN- of the TP4056 board. TP4056 has built-in overdischarge/overcurrent protection to protect the battery. It automatically cuts off the load if any anomaly is detected.

Step 4: Connecting the Load

One can power lighting load such as LEDs directly from the OUT of the TP4056 board. But for sophisticated electronic equipment which requires stable 5v power, we use MT3608 circuit. Connect the circuit as shown in the picture and adjust the output voltage as per the requirement of the load by rotating the potentiometer screw.

Now, you can give power to any electronic circuit by using this circuit. Harness the energy of the sun!