yeah them sortsa dudes
got one for my lawn mower
got one for my 'hyundai comes with a 12v cigarette lighter inflator instead of a spare tire' compressor
thought about hooking one to one of those $50 12v gear pumps that used to be around, but those became $90 while I was thinking about it
only downside is that they will run your batteries down below where the charger will charge them, gotta do a little farting around to get them brought back up
the battery drain thing does suck, and I'm still trying to get out of the habit to drain them before charging. my kids and wife are better about than I am now. just charge them, its not the old days of nicad... always reminding myself.
I've got M18 or M12 batteries on everything i can. just put one on an inflator, but usually have co2 bottles on hand. damn near everything I have is on an m battery, all the kids toys, m12 made the airsoft a bit hotter too. what doesn't run on M gets those 18650 batteries.
I ain't buying the M stuff just so the battery klicks in.
tranfer pump, radio, inflator all sorts of that type of stuff is way cheaper to just run an adaptor on. I have killed a few batteries, but I just need to be better about charging them all things considered in the years I've been running the m stuff, the batteries have been very good. I have a pile out back of bad ones, and there isn't very many for the 10+ yrs i've been running them.
before the adapters where a thing I used dead drill handles for the batteries. I don't go thru drills, one or two, but the shipyard did, so tool repair always had dead ones.