I bought my first 3D printed object, an adapter from one brand to another. (second and third where battery and tool holders for the wall, I thought that was cool there are practical mini-factories in peoples homes now)
It works well, I leave it in one tool (blower) we use a lot.
But I think theoretically mixing them might increase the chance of a fire or tool damage because the packs are different. Something something current cutoff, low voltage protection, no idea in practice if it's a real problem.
Battery tools are amazing and getting more Star Trek every year, try not to get the EU to slow them down too much.
Some brands put the protection in the battery (Milwaukee 20v does) others put it in the tool (EGO, Dewalt). If it's in the battery you're probably fine. If it's in the tool and you're using a differnt tool, a cheap hack would be to put a little voltage meter on it, and know what voltage you should not drop below. (I think it's 2.5v per cell on li-ion.)
It works well, I leave it in one tool (blower) we use a lot.
But I think theoretically mixing them might increase the chance of a fire or tool damage because the packs are different. Something something current cutoff, low voltage protection, no idea in practice if it's a real problem.
Battery tools are amazing and getting more Star Trek every year, try not to get the EU to slow them down too much.