Re: No they don't
I already do Richard :-D
I stick the 12v output from my little panels across a pair of 6v SLA batteries.
6v (often closer to 7v when charged) is a useful voltage... It gives me some voltage in hand for my cable run to the USB sockets by the bed and in the living room (and an LDO regulator behind the wall plate to put a final limit on it). One battery does each room. By complete fluke, they generally stay pretty well balanced.
Free charging for the tablets, phones, Satnav and all those other things with a USB power requirement.
Yes, Raspberry Pi runs fine too :-D
80% of the available energy delivered to the devices... Not bad for a DIY lash-up with bits I had laying about :-)
Okay, I know you were probably trying to save a little bit more energy on bigger devices.
You could always buy a TV, fridge and stereo designed for a caravan.