A passthrough that doesn't have the little box with the battery in it is supposed to vape at 5V. For the 510 you have to get BE510s (Rocky Mountain Vapor carries them.) I bought one with the battery and, as I'm getting a Chuck, I won't bother buying another but once the vendors start getting supplies from China again (now that New Year is over), I'll get one for my 801.
I have an AC to USB adapter (1,000 aH output) plugged into a surge protector that's right next to me. I use that for my passthrough so I don't have to worry about my computer.
Don't forget, with the exception of your BB, everything will wear out and you'll be replacing items bit by bit so, if you think you made any mistakes, you'll have plenty of opportunites to try alternatives. (And, as long as it helps keep you off analogs, it wasn't a mistake anyway.)