Introduction: Repurposing Mobile Phone Battery for Your Arduino Project

About: There's always a better way, just keep recycling those brainwaves!

This is how I recycled an old mobile phone battery for powering an arduino project.

This partcular type is s a 2000mAh nokia BLY4W. However the techniques used are common across the majority of phone batteries.

This battery suddenly died showing a 0 volt reading. I suspected that the internal battery protection circuit had failed.

this battery has a custom ribbon connector which is useless outside of the phone, so its got to go.

This shows how i took the battery apart and removed/replaced it with an external tp4056 charging/protection circuit.

if you dont know the dangers and precautions of handling lithium ion batteries, stop reading now.


I bought a mixed used and mostly new batch of 40 batteries for £10,. These batteries fit an end of line nokia Lumia model, which are no longer in demand, and hence the price reflects this.

Step 1: Strip It Down

1. using a sharp blade score around the plastic header.
2. prise the header off
3. disconnect the old protection curcuit.
4. apply kapton tape around the insulated terminal.
5. scrape off kapton above the insulated terminal head. be careful not to short curcuit to the surrounding metal.
6. scrape/sandpaper the terminal areas.
7. apply solder to tabs.

Step 2: Solder New External Charger Protection Circuit

i atached a male 2 terminal connector to the battery. Similarly a female connector to the usb tp4056 charging/protection circuit.

Ensure you have the correct polarity using a meter. On this battery the central header terminal was negative and the surrounding metal positive.

Step 3: Charge It Up (TP4056)

This tp4056 usb charging setup circuit goes blue when charged. it also has output terminals for your external circuit.

if your battery fails to charge to a blue 4.2v and hold its charge, bin it, you tried.

I boxed up the tp4056 charger and switched voltmeter display into a miniature potting box. It has a micro usb input and 2 pin terminal flylead charging connector for my various wired lithium batts. useful for charging and testing lithium batteries.

One thing to be wary of these tp4056 boards, is that sometimes they can lock up if you short circuit the output load. This requires a battery disconnect to reset it.