If it were worth the trouble, more people would be already doing it and there'd be lots of products to choose from. Unfortunately, it's not really worth the trouble, so no one is really offering anything of note. At 200 watts a large panel, you'd still need 5hrs of good sunshine to get 1kWh or 4 to 5 miles of range. Hardly seems worth the trouble. Better to setup a solar farm at the house, where you can make a small dent in your electric bill.
Not to mention you wouldn't be getting the sustained/constant 8A required by the Volt's on-board charger to even begin a charging cycle from that single panel...
Or spend $40k for 88 panels, ground mounting hardware, and a giant inventor to completely offset my power grid needs, yet, at 8.9 cents per kWh from the power company, the ROI just isn't there yet. Where I live cheap electricity means this is just a pay to be eco thing. Is it wrong to hope for higher utility rates like in cali to cause me to go solar? Just like, is it wrong to want to be t-boned so I can go shopping for a new car? Or is it wrong to want $5 per gallon gasoline so I can feel better about driving an electric car? The ROI for the volt was there at $3.50-4.00 gas (plus paying half price for a new car with tons of incentive applied) not quite there when we were under $2.
Solar Panels to charge your Volt=Pointless
Some do - but it just powers the HVAC fan to keep the cabin cooler when parked in the sun. Maybe help trickle charge the 12v battery too.
My 2010 Prius had a solar panel on the roof that supposedly generated enough power on a sunny day to run a cabin fan to bring the cabin temperature down to ambient. It sucked in outside air to reduce cabin temperature.
I think we have a better chance of seeing Mr Fusion in or lifetime vs. efficient enough solar panels where the hood, roof and trunk would be enough space to generate power to charge the battery while sitting outside at work. Though Ford had a concept at some auto show a few years back with a solar panel on the roof and a huge magnifying glass in a carport above to focus the rays of the sun. Thoughts of frying ants come to mind.
The lower 48 US states all have ideal solar potential of between 4 and 5 kwh per square meter. You pretty much ahve to be in San Diego, Arizona or New Mexico to get more than 4-and-a-fraction. That doesn't represent "average conditions", that's clear skies perfect conditions of just "sun through atmosphere" maximum output per day, with perfectly efficient equipment. Real world equipment is more likely to actually get 1 kwh per day per square meter, and the hood and roof of a car isn't likely to be much more than 2 or 2.5 square meters, so you're looking at MAYBE ten miles a day. More likely 7-8 on clear sunny days.
The 1366 watts per square meter is "in space, unshadowed, perpendicular orientation at about earth's orbit" figure. Once you get down to ground level in most of the US, dealing with latitude, atmosphere, pesky things like "night time", it's about 200 watts average over the course of a day/year, exclusive of weather conditions.
As is being discussed in the two posts above yours- even a quantum leap to 100% efficiency would still not be enough. You might have to locate the earth a little closer to the sun.
