cheb wrote: ↑Thu Feb 02, 2023 5:36 pm The one I linked to runs fine with a Makita 18V battery, and with a no brand 18V battery. Some makes use the higher voltage as proof it's bigger and better, the numbers of cells in the battery is the same. Also IME the motors in the tools will run on varying voltages quite happily. If the voltage is too great they run quite a lot faster, I ran a Dewalt 9.6V drill/driver on an 18V battery and it was good as a drill but even on the slowest speed it was too fast for driving screws easily. The bit tended to spin in the screw head at the slightly opportunity. The same battery in a 14.4V drill was fine for both drilling and screwing.
Think of lead acid batteries as fitted to cars and bikes, sold as 12V but when fully charged are over 13V. Stick a voltmeter across you battery terminals when it's fully charged and see what you get.
I checked both of mine, one Makita and one no brand, straight off the charger, they were both 20V give or take a tenth or two.