Don't connect directly to the battery, too much could go wrong. Just connect to + and - of the acc plug, the maker of the hand warmers should be able to let you know how to do that, this way you'll be protected by a fuse as well, and the hand warmers will not accidentally drain your battery if something goes wrong.That was a bare copper wire, I think it would not be a good idea to connect to that socket. I think the maker's idea was to let me connect the the ACC under the seat. you know, the tradition way
These are the photos are useful for assembly, I couldn't find my crimping pliers :frown2:, so I used long nose pliers to do my best, then soldered them :smile2:I've installed my heated grips cutting the wires just before they reach the AUX socket behind the headlight.
That's before I found the existence of proper connectors to do a cleaner job: https://www.ebay.com/itm/183383408094
I've then used these for a USB charger and it works fine.
Hooking directly to the battery as the generic instructions coming with the heatgrips are probably saying will work as well, it's the "universal way" to do it. That's good enough on older bikes without AUX ports on them, but on the G310, I think it just make sense to use any of the 2 ports already there for that purpose: fuse protected and no battery drain when bike not running, as Porth already mentioned.
I had similar to what is in your photos, and they doubled as a battery tender by disconnecting at that male/female plug and connecting the battery tender.I am not talking about the accessories with only two (+ and -) terminals, like oxford heated grips. I am talking about the devices like this Denali D2 unit which includes +, - and another trigger wire you can connect to another source which is consist with ignition (I dont think this third wire is taking a lot current, it functions like a logic to automatic shut off your device when you turn off the ignition). But I actually looking for this connector since a long time ago, because I have a ring terminals to SAE, SAE to USB wire. I can now convert the ring terminals to leads and connect to the port from your ebay link with no battery drain concern anymore.