Solar Panels for Auto Applications
 

Hey guys,

I was curious about using solar panels to increase an automobile's efficiency. I know that newer toyota prius have them.

Can anyone provide links for this sort of discussion/forum?

Is it possible to apply small solar panels to my car to assist with things like air conditioning, radio, etc.?

Any information is good information.

Sincerely,
The Dude.

Is there an area on your car that faces south at a 45 degree angle? because if you have the solar panels flat their output is going to be reduced by about 1/3rd because they will no longer be pointing at the sun.
Also the life span of PV panels is 50+ years and average life span of a car is 8 years altho some do last longer the cars that tend to last 50 years tend to be garaged most of their life and spend very little time on the road, so ingratiating PV in to a part of a car seems like a silly idea.
But with that said there should be enough space on the roof of your car that after all is said and done you should be able to get 40-50 watts out of the and with an average of 2-4 sun hours per day (again, not an ideal angle) that would mean 80-200 watt hours per day, plenty to run the radio (15-50 watts for regular car radios) and you might be able to find an electric heat pump/AC that would run off that amount of energy but it would be way cheaper to have it hooked up to a vent fan to bring fresh air in to the car in the summer, top off a deep cycle battery that could then help reduce the alternator load (DC-DC converter to get the voltage to 13.4v would be needed to keep the alternator off) and of course while you are driving it would help a bit too, assuming that it was sunny and the sun was high enough in the sky.

It seems like solar film would be the way to go. they can be integrated into body modifications relatively easily I would think and are not obtrusive as far as aerodynamics are concerned.

I do agree that the solar cells SHOULD outlast my (or any other) car's life expectancy. But, this of course, isn't really a problem, because if your car is ca ca anyway, it would be easy to re-purpose them elsewhere. You make a very good point though. It certainly would be important to have these concepts at the forefront of one's mind during design.

Yes. This "alternator" off concept is near what I was conceptualizing. Is this what the prius does with its solar panel? Is this turning the alternator "off" or just assisting it?

Thanks

The use of solar panels in cars really isn't worth the money invested, especially since they likely cannot be moved to a new car. The only worthwhile application I've seen is 1 to 4 amp trickle chargers.

The Prius uses them to run cooling fans when it's parked so the interior doesn't get so hot. That's probably the best use for solar.

For the amount of space they require that's all they can do in a car. It's a nice idea but I don't see it as 'economical' because it can't run the A/C (I'm told) and even if it can the pump is still attached to the motor eating up HP.

Best application of a solar panel for auto use? Tractor/trailers. Semis. There's about a hundred things you could do with that much square footage of solar panelling, and the weight of a few more batteries will not affect the terrible economy of a semi.
Do you know how much fuel they burn just to stay warm/cold when they're not driving?

Where can I "see" these applications? Can you send me the links?

all good stuff...

keep contributions goin...

Here's one at random
solar battery tender

Thank you Mr. Spammer for bumping this thread.

DieselB, here are two members that have used solar cells to offset the effects of going alternatorless:
Solar Roof
Paseo gets a solar sun roof

I've thought about putting solar panels on cars for a while. But I hear the panels are QUITE expensive. As a means around that I thought you could buy a bunch of cheap calculators with a small solar panel on them and take them out and rig them to your car. But that probably wouldn't work very well or at all hahahaha.

That's interesting that you mention this "calculator" idea. I keep crossing my fingers that I'll come across a school that's discarding their old ones.

It obviously wouldn't be cost effective to buy calculators for this use. But, hey, if you came across a lot of them for cheap or even free, it would totally be worth it.

Just gotta think outside the box!

Cars are a great place for solar. The military's been using them for years. This was my driver tracking mud all over the "No Step" sign, but the little solar panel shows up pretty well. They get parked for long periods, sometimes with the radios on all the time. No problems, at least with the batteries.
http://i1220.photobucket.com/albums/...o20Step202.jpg


Don't scoff at something being "only" a trickle charger. I slapped one of these on my shed once the snow melted and by the time I needed to use the mower it worked. Usually I have to drive out to the shed or push the mower back to the house so I can jump it the first couple times I use it. This year it started right up- not too shabby for $25.

Depending on your usage and where you park during the day, a DIY panel could replace your alternator: flexible solar panel - Google Search. I don't think it would help me too much, but you could probably turn your whole roof into a panel without having to know too much about electricity.

"The General rule to calculate the average charge time:

"Take Amp/hour rating of the battery and Divide by the charger rating (in amperes) and then add about 10% for the extra time to top off the battery, i.e. Assuming You have a typical full size auto battery, it is about 50 amp hours.

"To Calculate how much time You’ll need to charge the battery with a 15 Watt solar charger You’ll need:
1. Calculate the Ampere per hour of the charger: 15 Watts /12 Volts = 1,25 Amperes
2. Calculate the division: 50 amp hours / 1,25 ampers = 40 Hours of direct sunlight
3. Add 10%: 4 hours"
(retrieved from here: How to Use 12 Volt Portable Solar Powered Battery Chargers)

Seems useful. Maybe use a 100 watt charger, like this pretty expensive thing:
100w 12v,Semiflex solar panel,thin 2.5mm,Waterproof ! - eBay (item 260771192187 end time May-18-11 20:59:20 PDT)

This panel would nearly cover my whole roof.

After seeing a string of one-line non-posts, then the above advertisement, I'm reminded of a certain potted meat product...

edit.. the ad post was removed, so this post is in no way meant to describe anything else here.

Spacer, there is a little exclamation-mark icon (http://ecomodder.com/forum/images/em...ons/report.gif) in the lower-left corner of each and every post. If you click that, it will alert The Management to a problem with a post. Please use that button to report SPAM.

-soD

Oy, was just thankin' ya here, but it's off topic, so feel free to delete it.

I don't mean to sound like I'm scoffing at the idea. I love trickle charger solar and think they should become a standard. I t would be worth it for car companies to add a strip of solar in the dash of every new vehicle, but I would bet we never see it for ... well... a lot of dumb reasons mostly to do with hurting future sales by removing built in obsolescence.
If every vehicle had a trickle panel then we'd rarely find ourselves trapped and in need of a jump, but once you did you could be certain the battery was VERY DEAD. This is assuming that the car is smart enough to turn off the high wattage stuff.

I only said what I did before to imply that I don't think there are any worthwhile applications other than trickle charging. Does the cost of replacing the alternator with a car-length coating of solar materials equal out in gas savings within 10 years. Doesn't that much material add up to more weight than an alternator anyway. You reduce drag on the engine but add weight to the wheels and possibly deform the airflow over the vehicle. I just don't see it as a cost-worthy application of solar. I love to see experiments so I would never put down anyone who tries that sort of thing, but I will be practical and ask questions.
I still think we (as in everyone, not the U.S., not the ecomodders) need to find a way to start sheeting the top of semi-trailers with solar panels and convert all the trucks to run heat/air off that. Do you know how many states don't make it illegal to idle a semi while it is parked? I've talked to truckers that say they've sat at idle over 24 hours just to keep the truck warm. Some trucks are built smart and cut on/off, some have generators (which are usually gas and that is very funny to me).

Sorry, my 2 cents/rant is now complete.

Solar is not a bad idea if you have an understanding of the abilities of your application. If your car sits in a parking lot for hours a day, why not use some of all that free energy.

I am pretty sure that most of us here do these mods in part to do our part to help the environment; not only for financial reasons. Personally, I would rather spend my money on anything but OIL!!!

As some one has all ready mentioned, don't under estimate a trickle charge. In my case, pull over 300 watts a day. Usually more than that, but some times less if it is raining/cloudy. That is at 4 to 5 amps. - I use my system to trickle charge my deep cycle that I use in place of my alternator.

Depending on your vehicle, it would not be hard to remove or add your panel. In my case, I used the existing roof rack. It just bolted down to the existing fastener areas. - Probably got real lucky. :)

Another nice thing about having panels on your roof (elevated ones like mine) is that they help keep the cab cooler by blocking the sun, therefor I don't have to run the A/C.

Now just to be level here, though I have proven the application in a past vehicle, I am still building this for my current vehicle. I hope to be done in a couple of days. :thumbup:

I would eBay for panels and/or check out Harbor Freight. I did both. I found a nice panel for the Previa on eBay and I have a Harbor Freight setup on my barn. Good prices too.

Any who, sorry if I ranted and I did not intend to question any ones opinions. I am simply sharing my personal experiences.:p

It is a great project to under take. Remember to have fun!!!

I was looking for a fitting thread to post this, but found nothing better than this one that has been dead for 6 years...

So RAISE, ye olde thread!

Cause I got myself a small 5 Watt(ish) solar panel and attached it under the top of the trunk window, where the rear view mirror can't see it:

https://i.imgur.com/jiJF6M9.jpg

I wired the positive lead under the roof liner to the map lights, where there's a permanent +. The negative lead goes to the central ground just below the hatch lock catch.

I bought it cause my 12V battery is always reading below 12V if the engine does not run. I suspect one cell is mostly depleted, but the others are brimmed and prevent it from getting charged. So my panel will do that now, very gradually indeed.

I bought it at amazon.de.
https://images-na.ssl-images-amazon....SL._SX425_.jpg

Expect to only get 20 to 40% of name plate rating when putting them inside the vehicle, behind glass.

I tested it; it got just over 200 mAh in free air early afternoon, clear sky; and some 30 mAh in the fading evening light behind glass.
We'll see if it does tend the battery enough to raise the voltage to a healthier level.

The panel is meant for indoor use btw. That's why it can be very light, that's why I got it.

I already have a 9W outdoor panel, but couldn't mount it in or on the car in any reasonable way. It now charges our emergency torch. Behind glass...

Seems almost like it could replace a sunvisor behind the windshield.

I wish that I had seen a picture like this while I was in the Army. I never heard of battery tenders on military vehicles. In the Guard I always PMCSed my truck and then made sure someone had slave cables and a HMMWV.

Every month there were several dead trucks. We ran them until the battery was charged, turned off the battery switch, and probably slaved them again the next month.

It could, it even has elastic straps for that purpose. But my sun visors are too far back. Then, the hatch window is almost horizontal and the top is completely invisible in the mirror. It is the best possible location in my car.

I hadn't properly tested the charge current in situ. So this morning I hooked it up to my Fluke.

The weather could have been better:
https://i.imgur.com/lM2SCls.jpg

But even under cloud cover (no shades) it produces 30-40 mA:
https://i.imgur.com/xhQtjUW.jpg

And in the gaps between the clouds things get better:
https://i.imgur.com/RWZruy5.jpg

It had been higher than that (> 150 mA), but camera apps, handheld connectors and clumsy me conspired against capturing the moment.

Ah well. Good enough for its purpose. It will even charge a tiny bit on an overcast day. Voltage was up to 18 Volt unhooked, full cloud cover, and over 23 when the sun peeped by.

http://ecomodder.com/forum/member-fr...olarpanel2.jpg

This is mine, an OEM VW part. I use it on the Dasher because it's battery is weak.

I had my car serviced yesterday and forgot to unplug the solar panel.

The battery had been disconnected and during a test drive my UltraGauge could not find the OBDII signal. The car seemed to drive just as well, but one minute into the drive it threw a christmas tree of lights, alarms and warnings. The CVT control module had thrown an error which triggered all other systems to respond in style.
The dealer reset the codes and all was fine again.

I think the power from the solar panel kept some systems in zombie mode instead of properly shutting down, triggering error codes that threw off the rest.
Sure enough, since the reset no errors reappeared.

Lesson learned. Always unplug the panel before even coming near a dealership ;)

Not sure if this was the case with older panels, but I calculated a 14% reduction from flat to sloped. Not the worst.

Corrective optics from Fresnel lens recycled from dead big screen TVs?