If you have a 12/14.4/18 volt cordless tool with a dead or missing battery, then with a little ingenuity it can be used with an external 12 volt battery.
The current demand is substantial but easily supplied by a vehicle battery or similar.
At least #10 wire should be used, and not too long.

Not very convienient I grant, but cheap and works in power cuts, and safer in wet conditions than line voltage.