Lars Karlslund 
A friend gave me a broken laptop, with no clear problem description. There was no charger, so after rummaging around in my stuff, I found an HP charger that should work. The laptop was fine, but even though it said "charging" and had s an orange LED the battery stayed in 0% ... Reinstalling, BIOS update etc. didn't help, and the only stuff on YouTube was garbage. So it either the battery or the motherboard. Let's disassemble the battery!
So measuring voltage across the cells shows 0V output from the battery, and 1.2V across all cells (they should be around 12V to 16V). So the battery collapsed, it could still be the motherboard though. Anyway, I'm replacing the cells with some others I pulled from some laptops. After removing the old ones, I carefully weld new-old ones back.
This is my very much improvised battery welder. It's the transformer from a microwave, some heavy duty wire and a Sonoff wifi switch which I've programmed to switch on for 200ms and then off when I press the black button. Very ghetto, but it works really great.
Woooot, it works! It both charges and can run off the battery. Now I just need to reassemble the battery.
Epoxy FTW, I'm using it sparingly though. Just a little drop on the sides so it doesn't smear all over. It gets a larger helping inside though, so stuff doesn't rattle around.
verb (printfJess) 🦄@lkarlslund Epoxy resin is not designed for internal use.
@verb batteries aren't designed to be taken apart and refreshed like this. :-) Factory used silicone to hold batteries inside and cyano glue for the plastic to plastic bonds. What would you have used?
@lkarlslund a stick and some dirt?
@verb you make everything seem so easy
Kresten Laust@lkarlslund that's an awesome project
@lkarlslund are you aiming at your neighbours across the street when they have loud parties? What is this?
@verb battery welder! It transforms the 230V AC down to 2V or so, just with a huge amount of amps. It welds nickel tabs to the end of batteries, mostly without the risk of dying while you use it. There are lots of instructions on how to build this on the internet.
Jake Hildreth (acorn) 
kabutor@lkarlslund i like this, I read instructions to do one of those electric welder, to weld the pesky rs2032 to cables but I'm missing the microwave transformer.
Nice to see that it works
Nice to see that it works
Martin Boller 
@lkarlslund Pro ESD mat there