Lithium-Ion Cells Charger Using Dead Laptop Batteries ...

Thread Starter


Joined Dec 20, 2015
So Hi everyone ... i want to make a lithium-ion charger using the laptop batteries circuit boards ... but i searched the internet and i did'nt find any information cocerning this porject ... i'm a beginner and most the ICs in the circuit board don't have Datasheets in the Internet so i want to know :
1- How a laptop charge the battery in details please ... how much voltage enter in the circuit board ?
2- How the circuit board charge this cells and how could i control it's charging ... like if i want to charge just 2 cells or 16 cells you see !!
and Thx A lot for your help !​



Joined Apr 28, 2013
I never really every seen a setup like that cause the computer language need for the charger circuit cost a couple hundred bucks or so .. I would look at the Nitecore D4 charger and be done


Joined Jun 22, 2012
Laptop cells are usually 18650 type, 3.7v per cell and use battery monitoring pcbs to check the condition of each of the series cells upto 4.2v.


Joined Nov 4, 2013
You will be much further ahead to buya standard off the shelf LiPo battery charge balance board assy rather than try to hack a laptop unit.

The aftermarket units are mass produced and cheap so all you need to do is determine the number of cells you want to charge in series and find a suitable charge balancer.

eBay and Amazon would be my first two sugetions on where to look.

Ausama S.

Joined Jan 18, 2017
You can, but you need to have Cheap Chinese boards that they start and stop without the need to connect them to a laptop or any device
you connect the B- & B+ wire, boards like those might:
1. start after some seconds
2. need to connect "ID" pin to ground
3, Give it External power from P- P+ Connection..
Well the best way to charge batteries is use an RC smart lithium charger.
it can balance them and test their internal resistance and lots more.
Salvage Cheap Chinese boards and expensive batteries and make one out of them.
but after all watch about over current and over voltage, they Die really easily.
and always use a double plated metal in case you did something wrong while you learn and try and you find them burning..
Safety is No1 Priority.