solar deck vents for cars

[Brett Dikeman]

At 2:38 PM -0600 7/13/04, ben wrote:
>Hyatt (1990 200TQA) is getting old, but that gives me the opportunity
>to play with her, right?  Here's what I'm thinking:
>
>Most marine hardware stores offer solar-powered deck ventilation
>fans.  The idea is that you drill a hole in your deck and put one of
>these in, and get fresh air all day.  Sounds like just the thing for a
>car in Colorado, doesn't it?

Um....no...

>1) Has any of you done anything like this?

No.  Many rally teams install a forward-facing scoop that can be 
opened to bring fresh air into the compartment though.

>2) Any advice for drilling the 4" hole in my roof?

Um, don't, because nobody in their right mind would even consider 
buying your car, you'll look like a royal ass everywhere you go, and 
it's a complete and utter waste of time?

This is quite possibly the most bizarre thing I've ever heard.  Why 
can't you just crack the windows slightly?  Even in light rain, not 
much water gets into the car.

If you want to get crafty, you can install a DC fan in a location 
where it will either push or pull air into the car using existing 
vents.  The type 44 is designed to have fresh air enter at the front, 
exit through the rear deck, and out vents in the trunk, hidden by the 
rear bumper.  That flapping vent is the clunk you hear from the back 
of the car when you close a door.

A more elegant solution would be to wire a double-position relay 
between the blower motor and the motor speed control, and buy a 
decent-sized solar panel.  A switch (temperature or manual) would 
energize the relay via the solar panel (a solid state relay might be 
the best choice, you want very low power consumption) and connect the 
solar panel's supply to the fan's + side.  Wire the solar panel and 
relay -'s to ground.  A double-throw switch (temp or manual) might 
work well too, but make sure it is break-before-make and rated for 
the current of the fan motor(probably around 10A, but that's a wild 
guess).

I honestly have no idea how much energy it takes to get the blower 
motor to spin- you'll have to do a little sleuthing.  A little bit of 
speed, however, is all you would need.

Simplest solution?  Front and rear window screen reflectors. 
Everyone I've talked to who has one, swears by it.  Most of the 
problem is IR energy coming into the car and heating up the dash, 
seats, etc.  If they're about the same temp as the air temp inside 
the car, the car will actually cool off quite quickly with the A/C on.

Brett
-- 
"They that give up essential liberty to obtain temporary
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