laptop battery disassebled! now have 9 cells.. but wait...how do i test them?

[johnzm]

got 9 cells out of this laptop battery. it was pretty fresh but started flashing odd lights. i assume it has a bad or unbalanced charge in there. i ripped it apart.

so now i got here 9 118650 cells and i dont know what to do to go about checking, and verifying which are ok to charge so i dont blow myself up.

any help would be greatly appreciated thanks!

 

[ackbar]

use a voltmeter and make sure than none of the cells are 0V. Anything under 3V I'd toss.

 

[kramer5150]

just check the voltage across each cell. Any lower than 3.25V is no good.

 

[jasonck08]

As ackbar said, measure them with a voltmeter. If they are much below 2.8v-3v or so they may not hold much of a charge anymore...

I would also try to roughly verify the capacity of some of the cells after charging them up. If you have a charger that also discharges batteries great. If not then try using something simple like a 3W bulb from a flashlight or something. Then hook up a volt meter to it and see how long the bulb stays lit up until the volteage drops below 3v. Then you can calculate the capacity of the cell to know if its worth keeping or not.