Introduction: 15 Minutes Li-ion Battery Charger

About: Moroccan, husband, and father. I love technology, traveling, and reading. I've been to many places, and the more I saw the more I realized that what you may think is not always what is right.


So I had a laptop battery that could not power my laptop for more than 15-20 minutes. I replaced the battery and this one stayed on my desk collecting dust. I dismantled the battery and found inside 4 LG Li-Ion batteries.

I bought some components from AliExpress last year and among them was a charger chip of some sort.

I had some time to spare so I made a single battery charger in 15 minutes and here I share with you what I did.

Let's get started!

Step 1: Required Tools and Materials

To do this I used the following:

  • A piece of cardboard (I recycled one from a perfume box).
  • battery terminals (I recycled them from a toy).
  • Two lengths of wire
  • Soldering iron
  • Hot glue gun

The battery that I am going to use is an LGABC21865 Li-ion battery. The battery has a nominal voltage of 3.7v and a nominal capacity of 2800mAh. This was recycled from a laptop battery that went "dead".

The charging circuit is actually a LiPo battery charger circuit (TP4056) that I bought almost one year ago but I never used. I did search online to see if it's OK to use it to charge Li-ion batteries and the conclusion I have is that it's OK as long as the output voltage is not exceeding 4.1 volts. I purchased mine from AliExpress. You can find a link to the item here. It costs US $1.5 which isn't much, and is the only items that was new.

Step 2: The Build

The build is rather simple:

1- Cut the cardboard to fit the battery snugly.
2- Solder the terminals and the charger circuit according to their polarity
3- Use hot glue to fix the terminals to the cardboard
4- Glue the charger circuit to the cardboard
5- Glue the cardboard to make a simple enclosure

And just like that it was all done!

Step 3: Disclaimer and Future Steps

Please note that the charging circuit is cheap. I have no idea what kind of overcharge protection does it offer. it does have a green LED which is on if there is no battery or once the battery is charged apparently, but I can not guarantee that this is how it actually works.

This might be a useful instructable, but you should proceed with this at your own risk, and it goes without saying that I shall not be held responsible or liable for any loss or damages that may arise from attempting to recreate this instructable.

An improvement that I already have in mind is fabricating an enclosure made of acrylic sheets and perhaps using a proper Li-ion circuit to charge these batteries.

Thank you for reading this instructable, and if you have any ideas on making this little device better or if you would like to share any concerns regarding the circuit itself, please leave them in the comments.