I have an existing nema 14-50 at my house. I have the black 110v mobile charger. I also have the can jr and sr. What's the best way to connect the roadster to nema 14-50. It would also be nice to be able to hook up at RV parks on travel. It seems like this was something I should have been able to find by searching the forums but I just wasn't able to , so I appreciate your help.