Has anyone had any experience of the EZA power units from Roadpro Please?I know they are obscenely expensive but would like to know if they perform as promised.Would love to have a total solution to off grid power in the winter months but apart from generators(Boo! Hiss!!)can't find anything apart from the EZA that might do the job.WOuld have to sell the van to afford one though,which kind of defeats the object