How to determine dead cells

[patpatbut]

Hi all

I have some laptop battery to play with. I use voltmeter and find some cells are around 1v

Charge it up and they went to around 3.8v

Does anyone know how to check if they are dead?

Patt

 

[Deleted member 4366]

They're dead when they can't be charged. You need to check that they're not worn out. The only way to check is to discharge them through a load and measure/calculate the amp-hours. Worn out ones also sag a lot under load, which you can see with a watt-meter.

Most lipo chargers can charge and drain them automatically. A charging jig is useful to speed things up. during discharging, the lipo charger can be set to show the individual cell voltages, so you can chuck out any that go down faster than the others.

 

[patpatbut]

I am tempting to get a cell log 8S from Hobbyking. Will it be easier check the dead cell?

Pat