Solved: XPS 12 battery won't charge

If you google around, you'll see a bunch of users saying that their XPS 12s won't charge. They get questions and advice about changing batteries and chargers. Or...it must be the motherboard. I'm sure that's the case sometimes.

I saw enough of a pattern and new my equipment was okay, so I ignored that and focused on the bios (running A05, version on site was A08). Spoiler: it's a BIOS issue.

Here's the fun: the BIOS exe won't install if you have less than 10 percent power. So, you have no way to prove that you are in fact having a software issue. Right.

You can try to force the BIOS with /forceit. That won't get you anywhere. There's some people muttering about adding /hdrfile somesuch to a shortcut. Yeah. Didn't get anywhere there either.

Wonders: when you open the BIOS exe and it says 'you can't install me because you're at less than 10% power', it turns out that if you dig into your User folder, and then down into AppData, you can find the temp folder created by the exe sitting there with some random name, but a very recent file creation date. It has everything you need to update the BIOS.  if you click the okay box in the exe about not updating the BIOS, all this pixie dust will blip out so don't; that would delete these temp files, so don't click okay.

Instead, copy that stuff into another folder, say on your desktop. There's an ini file in there with some text about AC_Adaptor. Search for that and read what you can turn on and off. There's probably a 1 (meaning on) next to a battery check. Change that to 0. Magically you can now update your BIOS without having the exe treat you like you don't know what you're doing.

Run the exe you find in the same folder. In my case it magically fixed my problem.

So, what I'm saying is that there's a BIOS problem for at least some people that they have no way to solve unless they cobble together what I just did (because they didn't notice their battery wasn't charging and the machine died).

Give what I suggested a try...just be warned that if your AC adaptor loses power after you start the exe, then there's a change that updating the BIOS this way will brick your machine.