3rd Gen 2012 | solar ventilation system query

It runs as long as there's solar insolation and you haven't started the car (or go to IG-ON) or press the Remote A/C button.

The air comes out of all vents like it normally does if you have the fan running.

 

A few thoughts:

• Car does NOT need to be locked.
• The solar ventilation system won't start for ~10 minutes to avoid blowing A/C cooled air out of the car
• The air blowing in will be slightly above ambient thanks to the heating effect of the black intake cowling at the windshield. This is more prominent in desert temperatures.
• The system won't operate if the interior is < ~70°F
• The system only operates when parked as the solar panel potentially acts as a transmitting EMI antenna (interference) if allowed to operate while the vehicle is on. A relay disconnects the solar panel while the car is powered on. That said, turning off the switch while driving serves no real purpose.
• There's no real reason to cycle the switch - just leave it on. The off switch is if you know you're parking next to something stinky, like a sewage treatment plant, and don't want to blow that air through the car all day, or will be leaving the car unattended for days on end where the ventilation would only serve to needlessly run the fan and possibly clog the cabin air filter more quickly.
• The temp of the panels itself has nothing to do with whether it will operate, but cooler panels actually convert MORE electricity than hot panels, thus ironically, they're more efficient when we need them less.
• The panels are at a fixed angle. Parking with your trunk toward the southern sky in the Northern Hemisphere will make them slightly more effective.
• No matter how you park, the panels lose effectiveness 1-3 hours before sunset due to the extreme sun angle. The sun can and will continue to heat up your interior after this point, especially in the desert. Thus, finding shade is always better than solar ventilation.
• During the middle of the day, my system will operate on an overcast day, but not at full speed. Thus, some partial clouds (if thinner) won't completely disable the system in all cases.

 

The system isn't design to operate if the interior temperatures are somewhere below 70°F (unsure of exact temp, but the ECU doesn't operate if the outside temp is too low). Thus, the switch really isn't needed in this case either.

 

Yup. I can leave the switch depressed all winter and it won't operate and I'll get a nice gurgle in the spring on that one sunny day when it's still cold but the sun is strong enough to warm up the interior hehe.

 

It's more for if you're parked on a dusty road or if you're need a BBQ pit, you may want it off to avoid clogging up the cabin air filter (or having the interior smell of charcoal or wood smoke). Or maybe you're going away on vacation and don't need the car to run the fan while you're gone.

 

Nonsense or otherwise, this was a loose quote from one of Toyota's engineers when asked why the solar panel wasn't always active.

There is indeed an RF noise filter between the panel and vehicle ground (ref: 2010 Prius Electrical Wiring Diagram). However, there isn't necessarily a filter between the panel and (+) of whatever you choose to plug into unless you install one.

What exactly do you intend to do w/ the output? On a good day, you may get 60W out of the panel.

You also probably won't get very far unless you completely isolate the solar ECU, or replace it with something else.

There's a SPDT (single-pole, double-throw) relay that's affected by both the solar bypass switch and IG-ON. In the NO position, the solar ECU output is directed to the blower motor. In the closed position (energized by IG-ON or the solar bypass switch being switched off), the blower (+) is energized to the 50A Heater fuse. The solar output is never connected to the vehicle's battery system.

The Solar ECU also has inputs for IG-ON, which would effectively disable the unit. Once IG-ON is dropped, a 1 and 10 minute timer start in the solar ECU (which is powered by the panel). 1 minute to direct the face/foot damper to face, and the fresh/recirc damper to fresh. The 10 minute timer triggers the blower motor assembly start if sufficient power is present.

Point is here, you'd need to bypass that ECU entirely and find another method to connect solar output to whatever it is you're seeking to power. Make sure the panel voltage is compatible (it may not be 12V).