Laptop battery help please

Buttkicker · 2019-03-01T14:32:19.000Z

I have been getting various 18650 Laptop batteries from friends and sorting them out via charging - discharging - charging at .5amp
and today have come across two batteries form different laptops that ar 4.17 volts and one has a Mah of 4650 showing 98% on the charger so i took it out and the other one got upto 4400mah at 96% on the charge cycle
how can that be neither was hot warm but not hot
the question being are they bin fodder or re they useable

BlueSwordM · 2019-03-01T14:44:15.000Z

Unless you have more complex equipment like a CC discharger, very low current charger and some knowledge on how to recover 18650s,
I would just toss them out.

Not worth the work, knowing that they have extremely high internal resistance.

EasyB · 2019-03-01T15:09:56.000Z

It doesn’t sound like an issue that “recovering” can fix. If your charger really put 4500mAh in to an 18650 cell it sounds like there could be some sort of internal short. Leave it unconnected and see if the voltage drops a lot. If there is an internal short it will keep dropping. In any case, based on the info you’ve given it doesn’t seem like a good cell.

Edit: what is recovering anyway? My understanding is that when people say recovering they mean charging an over-discharged cell with a low current until a typical smart charger recognizes it as a Li ion cell.

BlueSwordM · 2019-03-01T15:12:16.000Z

It’s a much more complicated process than most people here can’t so, as it involves multiple steps and some knowledge of how lithium-ion chemistry behaves below 2V, along with how certain batches exhibit certain characteristics.

It’s also too complicated to write on a phone.

Buttkicker · 2019-03-01T15:18:46.000Z

there is two batteries going over the spec my charger does recognize them both,

Voltages are 4.17 will leave them and check in a few days and see what they are then thanks

EasyB · 2019-03-01T15:27:20.000Z

Bluesword: Ok I’ll take your word for it. But in the OP’s case the cells were charged, with 4500mAh put in. There is no mention of over-discharging. Are you assuming they had been over-discharged?

BlueSwordM · 2019-03-01T16:12:27.000Z

It basically means it is dissipating most of the charging heat.

SIGShooter · 2019-03-01T21:52:39.000Z

Well could be they are still only halfway charged if they are these

Macka17 · 2019-03-01T23:15:03.000Z

I do it the simple way. Strip Lappie casing. clean up cells. check ’em.
Put on charge till charger trips out.
Leave for 3 days. check with Multi . then stick in a “known” output torch
and see how long they last.
I stick with Toshiba and Dell.
they seen to have Sony, LG, or Samsung cells in there. (22-2600 Ma.)

My last Toshiba had LG. It would be 9 yr old now. the cells are still holding charge and power with regular usage.