# P.V.Panels to roof of electric van, worth the trouble?



## Guest (May 9, 2009)

Mere Drop. Don't bother unless you just want to keep accessory power charged up. Need lots of square footage of panels to make a dent. It is fun to do but no real benefit to motivating the vehicle down the road. These are heavy and not the custom very expensive solar racers that use solar only.

Pete


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## madderscience (Jun 28, 2008)

in full, direct sunlight you can expect to get roughly 100 watts of power out of a one square meter solar panel. So assuming you could use every square inch of space on the roof, and charging was lossless, you could get about 500 watts of power. At 48V, that is about 10A worth of current. As Gottdi says, that won't be enough to make a dent in driving. However that is enough current to recharge the car a significant amount over the course of a day. 

This is all optimal case though. Read up on what the 'peak sun hours' are for your area and what that means, and use that information to figure out how far from optimal your charging situation is going to be. You would also have to consider the weight and aerodynamic penalty of hauling all those panels around, and that you would need to always park in sunny places and try to angle the panels to catch the sun.

A better idea if you want to go solar is to put the panels on the roof of your home as part of a grid tied solar setup, where they can be aimed for optimal performance and can output at any and all times the sun is shining.

Good Luck.


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## High Tension (Apr 29, 2009)

Thanks Gottdi & Madscience, much appreciated. I'm minded to move house so [for me] fitting to the house roof would be too short-lived. I'll see how scary the 'bendy panels' prices are that are often fitted to boat decks with the view of a nice close fit. I was quite impressed at a trade show when the guy was busy walking on some demonstrating their qualities!


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## dtbaker (Jan 5, 2008)

madderscience said:


> in full, direct sunlight you can expect to get roughly 100 watts of power out of a one square meter solar panel.


high quality panels are up to 200 watts/meter, but still not worth putting ON a vehicle. Better to build a carport PV roof or put them on your house. Rough numbers are you will get 'about' 5x the system max on a sunny day with a static install (non-tracking).

a static 1kw system (5 to 7 panels depending on manuf) would generate about 5kWhr on a sunny day... which would get you MAYBE 20 miles depending on your EV.


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## High Tension (Apr 29, 2009)

Thank you Dan. My thinking was that as the vehicle will be used mainly during the day including a commute to work. Having the panels at home would render them useless unless I found a use for the power generated when the vehicle wasn't home. Having them on the vehicle meant that at least, [subject to parking 'in the rays'] the juice would reach it's target during daylight wherever it was.... These tiny vans sip power very gently so I'd optimistically hope for a fair amount of charge to be gained as my commute is about 16 miles in total....


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## Guest (May 9, 2009)

I understand that you are at work during the day and charging at home is actually not a realistic thing. One big problem you will have if you do decide to put panels on the vehicle is theft and vandalism. No place is immune. Build a solar panel charging station and use batteries to store your power. Use that power to charge your batteries at night. That is the only way or build a grid tie system and use the power from your panels during the evening. You do get out what you put in. Just make sure you build the system to give you more than what you actually need to charge up your vehicle. Or just pay the electric company for power and be good with that. It is better than paying the OIL MAN.

Pete


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## High Tension (Apr 29, 2009)

Pete, I entirely agree, anything's better than the OIL MAN! I hear what you say regarding theft and vandalism. Fortunately here on the Isle of Man it's a different world with such things although not unheard of, at an absolute minimum to mainland UK. Your idea of a home charging station is sound but would incur doubling up on batteries and control gear of course. 

I did just wonder that when the van is idle at home, [if panels were put on the vehicle], excess power could be taken from the vehicle and dumped into hot water heating.......


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## Guest (May 9, 2009)

Actually the biggest drawback to putting panels on a vehicle are making sure the panels are at a proper angle to the sun while on the vehicle. With such a small foot print it would be even more important to gain as much as you can from the panels you use. That means making a panel rack that can track the sun no matter what orientation your car is in to the sun. Parking lots are pretty random.

Pete : )


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## High Tension (Apr 29, 2009)

You're right, the angle is important. It might be a folly but I think I'll give it some serious thought and price it up. The wee van's due to arrive next week so I can measure up and see what's what, or should that be watts watt?... groan.


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## High Tension (Apr 29, 2009)

This seems literally incredible. Fit a Prius with a 30 watt, yes 30 and get 10% better mileage. Even my EV naive B.S. detector's blown a fuse on that one... http://www.treehugger.com/files/2005/12/flexible_ultra-.php


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## dtbaker (Jan 5, 2008)

High Tension said:


> Having the panels at home would render them useless unless I found a use for the power generated



if you have room for 3 panels ON the vehicle, and the thin panels (being less efficient) produce 150 watts each... 450watts X 5(at most) is going to produce maybe 1.5-2.0 kWhr per day at best. This might extend your range by 8 miles at most.... and on the downside, might mess up aerodynamics, increase curb weight, risk damage or theft.


...do a grid-tied installation at home. sell the power to your utility co all day... or talk your employer into letting you install a PV carport or awning at work. But the payback (even with good tax credits and REC buyback) is about 11 years, so you have to figure out how to own the equipment and take it with you or sell it to the building owner.

d


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## dtbaker (Jan 5, 2008)

High Tension said:


> You're right, the angle is important.


yes you get more effective area if the angle is right... but not THAT much difference in the area, especially in the summer, between a flat roof and a 20 degree angle. Heck, if you carted around two car ramps, you could park on an angle... 

but still... look into grid-tied installation if it is allowed in your area.


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## CPLTECH (Sep 14, 2007)

High Tension said:


> ...before I rip the engine out of my 'everyday skate' and play with this one first.


Does that mean you own one of the (in)famous P50's that the Isle of Man is so known for? The YouTube videos I've seen of them are neat. Sort of reminds me of what a USA scooter company, Cushman, made in the late 50's to enclose the rider(s).


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## High Tension (Apr 29, 2009)

Thanks Dan. 8 miles is half my mileage, so not bad really. Although I own the building at work alas there's room for anything to be added and if there was planning permission would take years alas. Here there's some resistance to wind farms despite the island being blessed with soooo much wind it would really make a difference. They'll have to see the light soon though. The energy company pay a pittance yet charge a fortune for juice so the best use for surplus would be water heating I'd guess. Maybe I should move to California!

I've made tilting PV racks before and found that it's the winter months when they're really useful. I've also played with reflectors alongside the PVs with some good results. 

Oh well, roll on Wednesday when I pick the toy truck up and start playing!


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## High Tension (Apr 29, 2009)

Ah the Peel 3 wheeler you mean? There's one in a museum here, an amazing wee thing it is too. Recently featured on TV when Jeremy Clarkson borrowed it and drove around inside an office block!

My truck is French, made by Aixam on 06. All aluminium and plastic, light as a feather, a cheap lucky* buy on Ebay. Flat out at 30 mph I don't think aerodynamics will come into it!

*Or unlucky if it turns out to be a disaster!


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## dtbaker (Jan 5, 2008)

High Tension said:


> best use for surplus would be water heating I'd guess.


direct heating is WAY more efficient for water.


hhhmmmm, how about non-roof-top 'awnings' to protect any south-facing windows you have? might slide right thru any architectual review?! check out my awning:
http://envirokarma.org/PV/gallery/080610_01.done.htm

ignore the 'high profile' array on the left.  The sunpower panels are available with black surrounding each cell instead of the white. It lower eff slightly, but appears a solid black from a distance.

d


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## ZEVUtah (Apr 10, 2008)

High Tension said:


> Thanks Dan. 8 miles is half my mileage, so not bad really. Although I own the building at work alas there's room for anything to be added and if there was planning permission would take years alas.


Put the PV panels on the buildings ( home and work ) and the van all three. To hell with the planning people. What are they going to do, sue you for NOT polluting the air. Get real folks. 

Here is my solar charge station and my car with roof top PV.

http://www.zevutah.com/

Boycott Exxon and all those other oily bastards. 

Cheers,
Kyle


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## Guest (May 10, 2009)

Here is our charging station. 7.2 KW Whole House System Grid Tie. 

Pete


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## ZEVUtah (Apr 10, 2008)

gottdi said:


> Here is our charging station. 7.2 KW Whole House System Grid Tie.
> 
> Pete


Very very nice solar system. I am envious for sure. My 1.5 kw system makes enough juice for the car, but I really would like to do more. 

Planning my next solar upgrade as we speak. Kind of adds new meaning to keeping up with the "jones" 

KJD


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## DavidDymaxion (Dec 1, 2008)

One counterpoint: If you have a bms that cycles battery to battery, a solar panel could prop up a low battery, or help keep batteries balanced.


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## High Tension (Apr 29, 2009)

A superb array! Very envious!


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## High Tension (Apr 29, 2009)

Trust me, the panels would be removed and p.d.q. too!


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## dtbaker (Jan 5, 2008)

gottdi said:


> Here is our charging station. 7.2 KW Whole House System Grid Tie.
> 
> Pete


wow, I thought my 5 kW was big. I don't have AC, but do have 2 refrigerators, a hot tub, and Zappy to charge....


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