I'm not sure it can be pinned down to one number. I think it depends on a few factors. I tracked the vampire loss over months and it is changing a lot. I decided that the inconvenience of waiting for it to connect when using the app on my phone isn't worth saving 1/6 of a mile in range or whatever difference it makes, so I keep it on 'always connected'. I do follow Tesla's recommendation to plug the car in all the time. I'm not charging it all the time, I only charge at night, but it's always plugged in.