I have a dual battery in my vehicle that charges while we drive. I would like to charge the battery in the camper trailer, using the dual/spare battery from the vehicle while the vehicle is not running i.e. drain the spare battery by transferring the charge to the camper battery. This is required when there is no sun for extended periods and solar is not working. Would the Irion TR smart 12/12 18 or 30 accomplish that. Can one set the under voltage shut down at different levels on the Orion so it does not damage the source battery?