DIY Arduino Battery Capacity Tester

I have salvaged so many old lap-top batteries ( 18650 ) to reuse them in my solar projects.It is very difficult to identify the good cells in battery pack.Earlier in one of my Power Bank Instructable I have told, how to identify good cells by measuring their voltages, but this method is not at all reliable.So I really wanted a way to measure each cell exact capacity instead of their voltages.

Few week ago, I have started the project from the basics.This version is really simple one,which is based on Ohms Law.The accuracy of the tester won’t be 100% perfect, but it does give reasonable results that can be used and compared with other battery, so you can easily identify good cells in a old battery pack.

During my work I realised, their are lot of things which can be improved.In future I will try to implement those things. But for the time being I am happy with it.I hope this little tester will be useful, so I am sharing it with you all.

Note : Please dispose the bad batteries properly.

Disclaimer: Please note that you are working with Li Ion battery which is highly explosive and dangerous . I cannot be held responsible for any loss of property, damage, or loss of life if it comes to that. This tutorial was written for those who have knowledge on rechargeable lithium ion technology.Please do not attempt this if you are novice. Stay Safe.

Step 1: Parts and Tools Required :