12V power tools battery?

Possibly an obvious silly question but couldn’t find an answer anywhere.

Would it be possible to power Arduino (& compatible) boards rated 6/7-12V with regular 12V/1-4Ah power tools li-ion rechargeable batteries (Bosch/Makita/Metabo etc)?

I don't see any reason you can't. 12V is 12V, wherever it comes from.

Better to use a buck converter to 5V and feed the 5V into the 5V pin, otherwise you are wasting more than half the battery capacity as heat.

Would be a good idea to check the actual voltage with a voltmeter, often the voltage at full charge is above the rated voltage.

I use a 12 cordless drill battery to power my robot. I made a 3D printed slide in mount similar to the one on the drill so the battery is easy to remove to charge. And a 5V DC DC converter for powering the Mega controller board.