[jacquesm]

You open them up, carefully document how they are put together, remove the cells, put new cells in and then put the whole thing back together. I've done this now for laptops, cameras, a couple of drills and a vacuum cleaner and they all work 'better than new' because the new cells have far more capacity than the cells that were in there originally.

[deng]

> remove the cells

I was under the impression that laptop batteries usually have on-board memory for holding charging parameters and such, and if you remove the cells, the memory contents gets lost and you cannot charge the battery anymore?

EDIT: More questions: Do you need a spot-welder for this? And how do you get the battery pack open, since they are usually glued shut?

[jacquesm]

> I was under the impression that laptop batteries usually have on-board memory for holding charging parameters and such, and if you remove the cells, the memory contents gets lost and you cannot charge the battery anymore?

Some do, most don't. I've yet to see one that was that tricky, though I would suppose there must be manufacturers paranoid enough to put that in.

> Do you need a spot-welder for this?

If you want you can buy cells with strips already spot welded on so not necessarily. But it certainly doesn't hurt, they're not expensive though. K-weld is one of the better ones.

> And how do you get the battery pack open, since they are usually glued shut?

That can be a bit tricky depending on the manufacturer they may have the whole rim glued shut or maybe only a few strategic spots. I've yet to find one that I could not open, but some do take a bit of patience. And once you know how a particular model works the next one usually goes ten times quicker.

I realize that what is easy for me may be hard for others, but this being hacker news and the fact that there is a substantial intersection with the maker scene here I don't think such a subject is out of place.

[deng]

> I realize that what is easy for me may be hard for others, but this being hacker news and the fact that there is a substantial intersection with the maker scene here I don't think such a subject is out of place.

Absolutely, your answers are much appreciated! I usually stay clear of fiddling with Li-Ion cells, as I have quite some respect for them, but I agree with you that replacing them yourself is probably safer than buying dubious clones.

[jacquesm]

I have a large article about Li-Ion safety in the works, but because of the material I have not yet published it yet, it needs to be bullet proof first.

[ho_schi]

I've replaced on my X220 the screen (TN->IPS), keyboard, bluetooth chip, memory and drive. But I really respect that cell replacement thing! Please share your knowledge! Maybe it is above my level but it can help everyone :)

[MaKey]

I tried this with a laptop battery where I guess the undervoltage protection of the BMS cut off the power. I was successful in replacing the cells but wasn't able to reset the BMS. How do you deal with this?