[mindslight]

That's much more of an explanation than I expected from my comment, thank you very much!

Reading between the lines, I think you've confirmed what I figured I had to do to replace the cells in my X230 - apply voltage across each of the cells as I swap them out, so the chip doesn't lock down.

But now I'm wondering if I can simply get a busted X220 battery to repair and use in my X230. The first search result says that it fits, but the X230 won't charge it due to DRM crap. But it also mentions a modded BIOS to get around this, and I'm running coreboot, so it seems that avenue might still be open - assuming it's really the "BIOS" and not the EC (embedded controller) chip checking.

BTW is gutting power tool batteries really a practical way to obtain reliable 18650 cells? It seems like that would be an expensive source, even on sale. But I admit my experience is with Dewalt 20V, which have their own premium. I figured I'd be hitting up the vape community to see their recommended sources when I got down to it.

[deeesstoronto]

The x220 battery definitely works with the x230 but requires the DRM patch. I'm running an x230 mainboard in what is otherwise an x220. It's an EC not BIOS path so should work with coreboot. Files at https://github.com/hamishcoleman/thinkpad-ec

While swapping cells, just be careful to match voltage and severely limit current to avoid any danger/excitement. Sure you can find some forum posts on this. Also, the new and old cells must be brought very close in voltage as discrepancies are flagged disabling the battery. This also goes for between cells but allowable differences are larger. I think this battery has 3s3p configuration.

I've bought quality 18650 cells online 10 for about $100CAD for a x220 battery rebuild. More recently got 2x 2Ah 18v Ryobi packs which yeilded 10x cells total for $29CAD on clearance at Home Depot....