awdinut

I can leave the windows cracked to let heat escape from the cabin...having the Solar Roof running the blower motor for hours just seems like a good way to develop bad bearings in the blower motor. BUT, having the Solar Roof ensure that I never have a battery too low to start the car sounds like a good use of the energy harnessed by the SR.

So, any of you electrical engineer types have a thought on whether that could actually be accomplished and if what would be involved is feasible ? It would be a great peace of mind thing to know that no matter how long the car sits without being driven the battery can not run down.

tsuter

richard-tx

I park my 2006 A8 in the garage. Original blower motor.

Changing the solar sunroof to a charger is pointless. It produces as much current as a AA battery.

awdinut

I'm a ***** cat, not an electrician, but it doesnt seem possible that the current produced by a 1.5V AA battery could run a big-*** blower motor such as we have in our A8.....what are you citing ?

And it doesnt take much to keep up with the drain on an A8 battery. My 4.2 ate batteries ate the rate of one a year because it had some sort of inappropriate drain going on. If I left the car un-used for a week, the battery would be too weak to start the car. But since I have not been using that car at all, I have plugged in one of the solar devices that come in Audi/VW units when they get shipped and the battery hasnt gone down. And that solar panel is small enough to place on the dash.

So it would seem to me like a panel with as many sq in as a sun roof could put out a sufficient amount of juice. Any one have the stats ?

ltooz_a6_a8_q7

It's quite simple to calculate the output of the solar panel on the roof.
The roof is about 20x30" and 2006 the solar efficiency is about 10% which would produce about 20watts per hour. I'm sure the system must have a big capacitor (battery) to store the electricity so it can drive the fans when needed.
20w/12.3v = 1.6A per hr.
Yes, you can charge your battery if you can find this solar storage, run a forward high current diode with it from the positive line to the positive terminal of the battery. When the voltage of the solar battery is higher than the voltage of the battery, it would charge.
The fans I think is about 5w, hence the fans can only runs so long before the juice runs out.
Find the solar battery, on a sunny day, measure across it to see what kind of voltage it is, I'm sure it's not 14v like the alternator. As long as it's above normal good battery voltage of 12.3v, it will charge.
Cheers,
Louis

Greg5OH

if someone makes a nice sexy kit for this id buy it