hmmm...not to do with mobiles ( unless you mean snow-mobiles) but the British Army has trialled 12/24V Solar battery chargers on the vehicle fleet at BATUS, under the Whole Fleet Management initiative (see this month's Soldier)
(If they work in Canada I guess they'll work in places with more sunshine!)
The ones in BATUS are called SOLARGIZERs and sit in the front windscreen attached to the sun visor.I understand they work so well they keep getting nicked!
The US company that make them are looking to roll these out to Police Departments in the US who, apparentely, have a lot of vehicles which are left standing for sevral weeks at a time....sound familiar ?
They tell me there are 31,000 Police departments in the USA......that's a lot of Solargizers !