Few months ago my Dell laptop battery did not work.Whenever I unplug it from main AC supply,the laptop switched off immediately.After few days of frustration, I replaced the battery and kept the dead one (as per my laptop message) for tinkering.I was curious what I would find inside it.Then I go through several blogs and forum to get some ideas.I got lot of things from http://www.candlepowerforums.com/.
Then I took apart the battery and charged them by using a good charger. By luck I found 4 batteries are in good condition. I used this battery to make a descent power bank. It really works fine for me.I thought I'd share the info to all. So that any one reuse it without throwing it in to the dust bin.
In this tutorial I will show you, how to harvest the 18650 battery from any of the old laptop battery pack you might have. Most of the time, laptop battery packs go bad when just one or few cells in the pack are dead. The protection circuit in the charging board cuts out the entire pack as a necessary protective measure for the user. There are still a few good cells though. At last I will show you how you can make a power bank by reusing these salvaged batteries.
Disclaimer: Please note that you are taking apart battery packs in this tutorial which is expressly discouraged by the manufacturer as this is potentially a very hazardous process. 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.
Full Project is on Instructables