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Toyota testing improved solar roof for EVs that can charge while driving

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Re: Toyota testing improved solar roof for EVs that can charge while driving

#91

Post by dghughes »

temporaryvector wrote: post #12

I live in a pretty hot city (My car's outside thermometer showed 48°C yesterday at midday). The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here. Hell, I'd consider it even if it would just keep the fa…

Electrically adjustable tint for windows would be a better option if it existed. Keep the heat out instead of dealing with it after it heats up the interior.

Just regular tint would be good too. I'm not sure if there are tints which block depending on the angle of the sun.

Re: Toyota testing improved solar roof for EVs that can charge while driving

#92

Post by mixmastamyk »

temporaryvector wrote: post #12

I live in a pretty hot city (My car's outside thermometer showed 48°C yesterday at midday). The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here. Hell, I'd consider it even if it would just keep the fa…

My old car had a sunroof that could also tilt up. That took the edge off and let excessive heat escape. Combined with a reflective windshield shade it worked reasonably well. Not chilly but more practical and env friendly than running AC for 8 hours a day.

Re: Toyota testing improved solar roof for EVs that can charge while driving

#93

Post by robotresearcher »

the8472 wrote: post #80
robotresearcher wrote: post #67

Earlier quoted context omitted.

How does that compare the the fraction reflected by a white paint scheme?

You can have your cake, eat it and get icing on top by using a coating that a) has a transmission window in the range that's useful for PV b) has high emissivity in the atmosphere's IR window c) has high reflectivity in the rest of the spectrum

That’s awesome. Either we don’t have those materials nailed yet, or the demo version pictured has the cells showing for presentation purposes, or both.

Edit: third possibility described by the interesting reply below: there could be an out of visible band reflective coating over the panels.

Re: Toyota testing improved solar roof for EVs that can charge while driving

#94

Post by tda »

seltzered_ wrote: post #49
temporaryvector wrote: post #12

I live in a pretty hot city (My car's outside thermometer showed 48°C yesterday at midday). The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here. Hell, I'd consider it even if it would just keep the fa…

2015 and later variants of the Prius already have this via the solar roof option: https://www.jpauleytoyota.com/blog/how-does-the-toyota-prius... “If you want to activate the solar powered ventilation system before you get out of the vehicle it is a simple process. On the left side of the steering column, you will find a small square button with a car and fan on it. Press this button before you turn off your vehicle…

The solar roof for running a fan has been around since the 2010 prius.

Re: Toyota testing improved solar roof for EVs that can charge while driving

#96

Post by the8472 »

robotresearcher wrote: post #93
the8472 wrote: post #80

Earlier quoted context omitted.

You can have your cake, eat it and get icing on top by using a coating that a) has a transmission window in the range that's useful for PV b) has high emissivity in the atmosphere's IR window c) has high reflectivity in the rest of the spectrum

That’s awesome. Either we don’t have those materials nailed yet, or the demo version pictured has the cells showing for presentation purposes, or both. Edit: third possibility described by the interesting reply below: there could be an out of visible band reflective coating over the panels.

Cells with such a coating would still appear dark to the human eye because the visible spectrum contains the peak of sunlight's energy distribution and you want to convert that to energy (you could optimize around the UV/violet range since the excess photon energy gets converted to heat there). But there's a broad limb of IR in the distribution that is useless because it's below the bandgap of most PV materials, that's the part you want to reflect. But then again inside the IR range there's the IR window, where you don't want to be reflective to increase emissivity to shed heat into space.

I have read research papers about such coatings, but I don't know whether they're in commercial use.

Re: Toyota testing improved solar roof for EVs that can charge while driving

#97

Post by mrb »

temporaryvector wrote: post #12

I live in a pretty hot city (My car's outside thermometer showed 48°C yesterday at midday). The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here. Hell, I'd consider it even if it would just keep the fa…

«somebody makes a car that can run the AC without running/draining the battery while it's parked»

Temperatures could be reduced significantly with a car modification that uses very little energy: a small fan to circulate and replace all inside air with outside air, and a one-piece reflective foil cover on top of the car, covering the entire windshield + roof + sides + rear windshield.

Re: Toyota testing improved solar roof for EVs that can charge while driving

#98

Post by jodrellblank »

helloguillecl wrote: post #85
ummonk wrote: post #20

Earlier quoted context omitted.

Yeah I'd want that in a normal ICE car.

Why would you want this feature knowing that is burning gas that you paid for while idle? Would you be happy about the car releasing toxic gases like CO and NOX while parked?

Because of the “going to the emergency room twice with heat stroke” thing, I’d guess.

Re: Toyota testing improved solar roof for EVs that can charge while driving

#99

Post by cortesoft »

temporaryvector wrote: post #41
hwillis wrote: post #29

Earlier quoted context omitted.

> The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here. Tesla's dog mode does this. Draining the battery isn't really something to worry about; AC uses <300 watts over long periods (turns on and off at…

I'm not sure how true that would be in extremely hot weather, but it is probably the only reason I'm considering a Tesla if it ever comes to my city, my commute is really short so even if it cut 200 miles off the range it'd be worth it for me. Having a car with remote start alleviates the problem a little bit, but I'd rather not run an ICE engine while I'm not in the car for obvious reasons.

What do you mean by 'if it ever comes to my city'?

Re: Toyota testing improved solar roof for EVs that can charge while driving

#100

Post by cortesoft »

hwillis wrote: post #29
temporaryvector wrote: post #12

I live in a pretty hot city (My car's outside thermometer showed 48°C yesterday at midday). The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here. Hell, I'd consider it even if it would just keep the fa…

> The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here. Tesla's dog mode does this. Draining the battery isn't really something to worry about; AC uses <300 watts over long periods (turns on and off at…

You can also just turn on the AC from your phone 10 minutes before you leave. Or, have it learn your schedule so it prepares your car for you before you go.
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