Lol, I get it, I often start doing the math and realize "someone has already done this".

Cool, thanks for the link. I already knew the little 12v batteries suck (though they work fine for the intended purpose, like impact driver or work light). I kill them with any other tool.

Yea, I was just thinking is the runtime reasonable enough that having spare batteries is a sufficient approach. Like you said, long runtime isn't required, 15 minutes total runtime is probably more than enough (though that would be hell on battery life cycle).

Since I already have a slew of Milwaukee batteries, I'm trying to avoid things with 18650, except where form factor matters (like my flashlights). A Single Battery to Rule Them All (or at least most things).