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Car roof mounted photovoltaics

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To increase the utilization efficiency of energy, the i MiEV SPORT is equipped with a photovoltaic generator attached on the roof and a power-generating fan inside the front grill.
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When the car is slowing down, the fan inside the front grill is rotated for the power generation.

Waste Of Money, Brain And Time - WOMBAT

Better tweak your regen. For much less money you'll benefit much more.
 
You could put magnetic induction coils under the freeway and recharge as you drive.

They could make them oscillate such that you have to go the speed limit to get power.
 
Trickle-Charge Stored Vehicles w/Solar | EarthTechling

Worried about draining the battery of your ATV or RV as you store it away for the season? Now there’s a new solution for keeping vehicle batteries charged, courtesy of 100 percent solar energy, the SUNfilm Solar Battery Charger from Carmanah Technologies Corporation, part of a line of chargers developed for the company’s Go Power! brand.

Available as a 1.5 watt, 5 watt or 15 watt module, these solar chargers make use of thin film solar technology to trickle-charge all battery types, including 12V deep cycle, automotive, motorized sports vehicles, RV and fleet vehicle batteries. Each includes quick-connect accessories designed for easy installation and — as an added bonus — can be modified into portable charging stations for mobile electronic devices such as cellphones and mp3 players.
SUNfilm Solar Battery Chargers

image via Carmanah Technologies

Designed to operate either on the exterior of a vehicle or inside, on its dashboard, the SUNfilm chargers will kick out juice for your application in overcast conditions as well as on sunny days. A built-in diode (5W and 15W) prevents reverse charging when connected to the vehicle battery.

The chargers work with small electronic devices via an adaptor (included), and are available throughout the US and Canada.

SUNfilm Solar Battery Chargers | GPElectric


SUNfilm Solar Battery Chargers

Go Power!™ SUNfilm Solar Battery Chargers are made from thin film technology that is lightweight and economical. The series is ideal for maintaining your battery’s charge during periods of inactivity, to protect against constant discharge from on-board computers, electronic systems and devices.

The SUNfilm solar series is perfect for trickle charging:
• Deep cycle + Automotive batteries (12V)
• Motorcycle, ATV, snowmobile and marine battery
• Electronic device chargers (with the use of an adaptor)
Features and Benefits:

includes adaptors to charge mobile devices
portable thin-film technology
easy to use and maintenance free
built-in diode (5W and 15W) prevents reverse charging and the durable
module can be mounted for use in both exterior and dash board use

GP-SF-1.5 GP-SF-5 GP-SF-15
Rated Power 1.5W 5W 15W
Peak Current 0.12 A 0.26 A 0.9 A
Working Voltage 15 V 15 V 17 V
Open Circuit Voltage 22.5 V 19.6 V 20 V

GP-SF_Family.jpg



Would this be usefull in an EV?
For heating or cooling?
Or are these PV-pannels still not powerfull enough?
 
I can't recall the exact number but I want to say that the PV roof on the Fisker will only generate like 60-miles of range in like 10 years of service. It's way more trouble than it's worth. As malcolm said, put a bunch on your house and be happy.
 
I must point out that panels on the car are the only ones that actually contribute to zero emissions driving, unless your home system goes into a battery storage bank, or your car is plugged into it during the day. Grid tied solar just feeds the grid, you can have it with or without an EV. It can offset your driving costs, but coming home at night and plugging into the grid means a power plant somewhere needs to put out a bit more juice.
 
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I guess it depends on where the additional nighttime load compensation comes from. If your night time charging comes from coal and your daytime grid fed solar offsets NG then over all emissions are higher. Of course the reality is that grid tied solar is probably putting more kWh's in to the grid than your pack requires, a lot of variables to consider.
 
It's impractical to size a home-roof-mounted solar PV system + storage bank so that worst-case energy yield (=period of bad weather/snow) matches worst-case energy-demand (Roadster empties his pack for several days in a row). You'd have massive amounts of excess energy that you want to feed to the grid.
My worst lull this year was in January (=snow). My 10kWp system harvested a mere 13.5kWh in that week, that's a 1/4 roadster charge and equals 55 miles.

I can see the desire to keep an EV topped up when camping far off the grid for several days. I'd like to have a portable set of PV modules, mounted on a tripod and tracking the sun for that.
 
These kind of PVs are very useful in specialized circumstances. I have one on my sailboat to keep the battery trickle-charged; otherwise, the bilge pump can run the battery dry if I'm not careful. But that's the scale where these mountable PVs are useful, not in providing motive power to a BEV.