Solar powered ventilation system

[rytis]

Has anybody thought about running the vents on the Yaris with solar panels?
Similarly like what they did on the 2010 Prius, a solar powered ventilation system to keep the car cooler when it's parked on the sun.
The weather is getting really hot, and my Yaris is baking in the sun. It gets super hot inside, and such a system would bring the temperatures lower without having to leave the windows open.

Would someone know how the connections would need to be made, so that the solar panel would drive the fans when the car is parked, and, not interfere with other components and normal operation of the fans?

Thanks!

[derickveliz2]

Good idea, wonder if we can really do some thing like that, I've been looking at these cheap solar fans but I don't know how good or bad they are..

http://www.1topstore.com/images/products_images/unfurl/bf17.jpg

LINK (http://www.1topstore.com/product_info.php?language=en&currency=USD&products_id=4605)

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[rytis]

Yeah, I've seen those too. I wonder how well these work also.

But using the existing fans and vent system would probably be much better, and a nice DIY project :) . Windows would remain closed, air would pass through the filter and only the solar panel would be needed to be placed somewhere under the sun.

Maybe someone here knows how many watts the Yaris's fan / fans consume, so we can determine the solar panel size we need.

[Revsson]

Yeah, I've seen those too. I wonder how well these work also.

But using the existing fans and vent system would probably be much better, and a nice DIY project :) . Windows would remain closed, air would pass through the filter and only the solar panel would be needed to be placed somewhere under the sun.

Maybe someone here knows how many watts the Yaris's fan / fans consume, so we can determine the solar panel size we need.

Sounds like a CTScott project...:smile:

[Yarisduder]

The motor of the fan should have the current draw written on it, if only it was easy to get at...

[yarrr]

Window tint and a sun shade for the front. Call it a day.

If the car isn't moving and not on, you'll just blow hot air in the car. The hood and the air inlet just bake in the sun and absorb engine heat and heat all the air you are trying to get. I also have doubts on any reasonably priced solar system will be able to power an A/C fan.

[rytis]

I was just thinking about getting window tinting and a sun shade. How much can you get the tinting done for? And how much sun do they reflect? I imagine the mirror surface ones reflect the most.

[Yarisduder]

Maybe the fan could be run in reverse, therefore expelling the hot air. Is there a vent to prevent a vacuum.

Looking at the wiring diagrams the blower motor is on a circuit protected by a 10A fuse, so we can assume that we need a 10A supply. That would be 120 watts; a fairly large solar array to power the fan directly, but if you use a battery it could be charged by a solar panel, or more quickly by the car while driving. If you want it to run 6 hours, that's a 60amp/hr battery, which I believe is about as big as the car's starter battery.

The motor may draw less power at lower speeds, then again it seems to use resistors to adjust the speed so it may draw less at the highest setting.

[rytis]

I found the diagram here:

http://circuitwiringdiagram.com/2010/02/electrical-wiring-diagram-toyota-yaris-2007-blower-motor-circuit/

http://circuitwiringdiagram.com/wp-content/uploads/2010/02/toyota-yaris-blower-motor-circuit-wiring-diagram.png


I also looked at the Yaris fans, and they seem to draw 7 amps and up. But we don't need to have it spinning fast, so I wonder what's the current draw on speed 1. Could it be 1 to 2 amps? If so the solar panel would need to output about 12 to 24 watts. Just guessing.


Running the fan in reverse is a great idea! It might workout better. That way the heat build up from the top of the hood where the vent intake is wouldn't be sucked into the interior. But then again, the car isn't air tight, so the air will have to come from somewhere. I wonder where that would be.

[talnlnky]

Personally I think if you were to do the solar vent idea, the most efficient way to go about it would be to push the extremely hot air out of the car, whereas if you used the existing fans you'd be pushing hot (tho not as hot) air into the car.

The idea is to let the hot air escape... so why not do that instead of trying to force cooler air(tho still hot) in?

I doubt you can get those fans (stock vents) working in reverse tho.

[bkrownd]

Unless there is mass quantities of solar juice available I highly doubt the dash fans would be the most efficient method of removing hot air.

Creating a simple chimney effect and adding some puny solar fan to encourage and assist the flow a bit would seem to be the most efficient method, and should be adequate. So, grab a little 3" chimney pipe and a chimney topper thing from Home Despot and start by cutting a 3" diameter hole in your floor and a matching one in your roof....

[derickveliz2]

I have a better solution...


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I'll park under a tree! LOL:w00t:

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[rytis]

Too bad they cut down most of the trees in the city, so they're not always available... and I live next to a park!
It's under a tree right now actually, but I got lucky this time :)

Don't feel like making holes in the Yaris. Just want to drive the existing vent system.

[severous01]

talk about burning up a motor...better have extended warranty.

[rytis]

I don't think motors burn up too quickly. Especially when it won't be spinning fast from solar power.

[Yarisduder]

I looked a bit at solar panels and just a 5 watt panel is surprisingly large. Where were you thinking of mounting them?

[severous01]

they make solar kits you can mount in the window, for like 20 bux at jcwhitney.com.

[squirt1982]

I'm pretty sure the fan is centripetal. In other words you can't run it backwards, it'll simply blow the same direction just very inefficiently. Correct me if I'm wrong though.

[Yarisduder]

Yup it is, just checked. I thought of that when I suggested to run it in reverse but didn't check. Sorry.

Just saw some solar panels, for 5 watts you've got a unit that's about 8" x 8" and roughly $30.

[CTScott]

As an FYI, the fan draws 1.94A @ 12VDC. Running it at one of its lower speed settings doesn't reduce the current draw, it divides it between the blower motor and large resistors (A.K.A. heaters) to make the motor spin at lower speeds. So, theoretically, a 24W solar panel could run it, but more realistically, you'd need a 50W one, as the ratings are based on perfect conditions. You'd also need an appropriately rated diode to prevent the battery from back feeding the solar panel when the ignition is on.

I really don't think that this would be very effective though, as the air intake is the black plastic wiper cowling, which would do a good job of heating the relatively slow flow of air into the car. Also, unless you left your windows partially open, the hot air wouldn't escape from the car.

Having a moon roof on my Yaris (and a sun roof on my Xterra), I would have to say that a roof opening is by far the best way to let some of the heat out of a parked car.

[rytis]

I bought a windshield solar reflector (which specially fits the Yaris's windshield) and it seems to do a pretty good job, so I lost some motivation for this solar powered ventilation idea.

Thanks for all the info.

I'm wondering, so when I'm using the fan, it has the same power draw no matter which 1-4 speed I use?
Wouldn't it be possible to connect those 5 watts of power directly to the fan, and not having it pass through those large resistors (A.K.A. heaters)?

[Yarisduder]

If the fan is set on 4 then it bypasses the resistors, if it's set any lower then (other than 0) it uses the resistors to limit the speed. You could bypass the normal circuitry using a relay or something, in fact you probably should.

Here is a solar powered vent, you could drill a big hole in the roof and pop one of those in. It would be easier and the extra chrome would look pretty slick!

http://www.wsetech.com/images/SVT-012S.jpg (http://www.wsetech.com/sunvent-fan.php)