I kept working on the PCB schematic. After tidying it up a bit, I decided to make a device and footprint for the battery I’m going to use. It’s kind of standardized with dimensions of 10x34x50, A type with 2000mAh. That’s it, I made a rectangle of 84 by 165mm and put some holes 5mm away from the edges. I still need to figure out what type I’ll use, whether it’s countersunk or not. But either way, between 2.2 and 3mm.