When it comes to building projects we generally use a power supply for prototyping, but if it is a portable project then we need a power source like 18650 li-ion cells, but these cells are sometimes expensive or most of the sellers don’t sell genuine products. So in this post, I’ll show you how you can extract some good quality cells from old laptop batteries so let’s get started.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Watch the Video!
If you don't want to read all the stuff you can watch my video tutorial
Step 2: Finding Old Laptop Battery Packs
The very first step is to find out some old laptop batteries, you can go to the nearby scrap yard and ask them if they have and that’s what I did or you can search online on eBay for some listings. I brought these 6 batteries pack only for 14 USD, which is already way cheaper than buying them on first hand.
Step 3: Tearing Apart Battery Pack
Now all you have to do is take a flat head screwdriver and carefully remove the outer covering. I generally first find a weak spot like a border and slowly start tearing it apart, Once you can see batteries inside you can use some brute force to tear apart the plastic.
Once it is done keep the cell pack as it is and repeat the same process for the remaning battery pack, we will come back to it later
Please be careful as plastic can be sharp inside!
Step 4: Separating the Batteries
Once you are done tearing all the battery pack take a diagonal cutter or a metal snipper and separate all the batteries and also remove the circuit as we don’t need it but don’t throw it away as we can use it for a future project.
Now let’s continue separating them. After that remove the metal pieces from the battery top and bottom as well.
Step 5: Charging the Cells
Now we have to charge all the cells, but before that, we need to separate all the cells according to their conditions, Take a multimeter and measure the voltage of the cell,
If the voltage is more than 3v it’s a Good Cell
If the voltage is in between 2.5v to 3v then an average cell
And if the voltage is less than 2.5v it’s a bad cell and throw it away
To charge the cells we can use IMAX charger or one of those tp 4056 modules.
Since one charger was not enough I borrowed one and also used tp4056 to charge the cells.
Charing Current for cells should be as follows,
1) 3.7V, 1 Ampere for cells with voltage greater than 3 volts
2) 3.7V, 0.75 Ampere for cells with voltage in between 2.5V and 3 volts
3) if you want to try recovering a dead cell which has voltage less than 2.5V then voltage should be 3.7V and 0.5 Ampere or 0.3 Ampere
Monitor the temperature of the cell if it gets too hot then immediately remove it from charging!
Step 6: Capacity Testing
The last step is to check the capacity of the cell which is crucial for that I used my DIY capacity tester,
and separated all the cells according to their capacity. And that’s you can now use these cells for your project!