Love it! You forgot to mention you arrive charged most of the time since it is charging while you are on the road.

I think it is a great idea, even with some of the concerns mentioned above. You could also back it up with solar panels I would assume. I am tired of my noisy generator breaking down and having to pay almost a $1000 to get it fixed (the built in one). Plus they always keep my RV for a month to fix it, ugh! In fact I now just bring a small Yamaha generator and bypass the main generator. If it needs service, I am not tied to the high RV repair center costs. At worst I could just buy a new one and it still would be cheaper.

GU generator ? it just a large alternator, doing what they ALL do make DC for batteries and then you power everything with a large inverter, especially if you want 120vac just moving all the expense into the inverter and batteries yes i think all Rv's should come with a BIG Alternator, for battery charging but running the much bigger DRIVE engine just to charge batteies is NOT really more fuel efficient , yes it is much less work and eaier on the big engine, but your turning all that weight and using all those cylinders just to charge the batteries, that a smaller more fuel efficient engine can do this is very heavily biased ADVERTISING

Are there any mechanical concerns to idling a gasoline engine so much?

So when the battery power supply is used up you need to pack up and get going?Or can we expect Hymer owner to disregard rules about idling engines?Not so brilliant solution at all... sorry.

the placement of the under hood generator concerns me. too exposed to go little off roading in, I think with a 4x4 set up.

Seems like a very expensive way to generate power. A small generator, despite its drawbacks, is much more fuel efficient than a big engine designed to move the entire RV.

PLEASE bring us the 4x4 Sprinter!