Solar Powered Charger for 18650 Lithium Ion Cells

Intro: 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:

• Solar Panel 5V - 6V (2 Nos. Depend on power, should be more than 1 Watt.) http://bit.ly/2OkqY3Q or 10 Watt version for fast charge: http://bit.ly/2OivXC8 10 watt version makes much economic sense as it is very cheap.
• Lithium Ion 18650 Battery (Avoid Batteries with names which contain "Fire". They are worst.) http://bit.ly/2mJkfUk or http://bit.ly/2Aab7Se or For Bulk: http://bit.ly/2Ogtzff
• 18650 Holder: http://bit.ly/2AdAF11
• TP4056 Circuit Breakout Board (with over-discharge protection): http://bit.ly/2JY1Qg1
• MT3608 Breakout Board: http://bit.ly/2LzUunL
• 5V 2A Boost circuit (Optional): http://bit.ly/2uQ5ZOa
• DuPont Wires Female to Female: http://bit.ly/2JTBGLe
• Header Pins
• Normal Wires
• Solder Toolkit http://s.click.aliexpress.com/e/eayjqRn
• Soldering Iron http://s.click.aliexpress.com/e/FmAUZvn
• Knife

From Amazon:

• Solar Panel 6v 0.6W: https://amzn.to/2HBLPww
• Solar Panel 6v 6W: https://amzn.to/2Hs1zVi
• Lithium ion 18650 Battery: 1. https://amzn.to/2H3HiGh 2. https://amzn.to/2H3HiGh 3. https://amzn.to/2H3HiGh
• 18650 holder: https://amzn.to/2voXFI0
• TP4056 board: https://amzn.to/2vjP9tx
• MT3608 board: https://amzn.to/2HqouQW
• 5V 2A Boost circuit: https://amzn.to/2qB3eOK
• DuPont Wires: https://amzn.to/2vl3WUU
• Solder Iron Kit: https://amzn.to/2vhM5yn

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!

Comments

[Matty icep]

Should there be a diode connected to the solar panel to prevent reverse current for when the sun is not shown or is it unnecessary because of the 18650 charger prevents this?

[xrtekk]

Definitely! Even though someone said that there is no need to this project; consider that: You want your solar panel to last; so YES; add a (easy to replace) diode (so it can be easily replaced when burnt; to prevent damaged solar panels due to current going back (which increases temperature on the solar panel if current goes back).

Note: This is specially important if the project is adapted for a 12v with 18650 batteries. The 12v Power going back to the solar panel will greatly increase the heat in the panel and it will likely melt or burn.
Yes: I’ve done such noob mistake; but added a diode to solve the problem.

[chimeranzl]

No need, panel is too small for to be concerned about reverse current.

[CameronM37]

One concern I have with this circuit is that it looks like you can have a load and a charge on the TP4065 at the same time. This is dangerous because the TP4065 is not smart enough to know that the load exists and will give it a false sense of charge state and potentially overcharge the 18650 cell. This can result in fire or explosion.

If you introduce a DPST switch such that the battery can either be charged OR the load can be connected, you will avoid this scenario.

Other than this concern, this is a very cool instructable!!! Bravo!

[plbenn]

I have built this and it is working successfully but now I've seen a recommendation for a similar charging module which I will implement. The TP4056 module and the one pictured are both rated at 5v input. A 6v solar panel will supply more than 6v. The recommendation is to use a step down buck converter between the solar panel and regulator so that the regulator is only getting 5v at the input.

[rohantatkare]

A nice project to be used in rural areas !!!

[FlyingGuy99]

Just a question:

Your picture is showing parallel wiring which serves to increase the amperage (not the voltage). However, in the instruction text you mention "Connect solar panels in series as much as you want". I think you really meant to say "Connect solar panels in parallel as much as you want", is that correct?

[bishaldutta]

That was an unintended mistake. Corrected. Thanks for pointing out.

[DIY Hacks and How Tos]

Great first insttuctable. Very well written.

[bishaldutta]

Thank you!