Power sockets, USB A / C plugs… What’s the best / proper / most wildly used tag? It would be handy so that I can search for anywhere to charge my mobile device, whether it’s amenity=power_supply, power=outlet, amenity=device_charging_station (as you can see the list goes on, and it can be very hit-and-miss). Instead here the focus is the function the element on the map serves, a bit like ‘drinking water’ (there are many ways of providing drinking water etc.).
This is actually something I started tagging at some point, specifically as a place attribute à la toilets=*. I tag power_supply=yes on the place POI and then for more detail I use socket:*=* tags. I actually even made a very basic MapComplete theme using this tagging concept. (It’s not quite fully ready for primetime, but it does display and edit data for NEMA 5-15, NEMA 5-20, and USB-A.)
Also for a more direct answer to your question: I’m pretty sure there’s no tagging scheme that’s been formally approved. As a POI attribute, power_supply=* was originally made for camp sites but my tagging is a pretty straightforward extension. As its own thing, as you noted, there are quite a few options. I will at least single out power=outlet and caution that that one’s intended for micromapping individual outlet locations, so it’s a little different from the others. As far as usage, I see from taginfo that amenity=device_charging_station has 1073 uses vs. 728 for amenity=power_supply. To my knowledge, those are your options to pick from.
I bet a graphical icon for organic maps too (the most popular OSM client) would make it widely used, but I suppose that’s a whole other topic (I’d be happy to work on the technical stuff myself :), feel free to send me useful wiki links / other).
'Cause it’s definitely a highly requested feature, in fact I’ve seen more than one case in which it was switched for an electric vehicle charging station, which is definitely not what we want!
Yes, that’s right. As far as your Organic Maps idea, if you want to propose that directly to Organic Maps, you can try opening an issue (or submitting a pull request, if you feel confident trying to implement the feature yourself) on the Organic Maps GitHub repository; however, you may be able to strengthen the case a bit by first creating a formal proposal, which power_supply=* has still never gotten, to my knowledge (though the wiki page does refer to an abandoned proposal from 2009 pertaining specifically to camp sites). I don’t feel like I have the time these days to do so myself, but if you’d like to give it a shot, I’d be happy to provide whatever support and resources I can.