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

I live in a pretty hot city (My car&#x27;s outside thermometer showed 48°C yesterday at midday).<p>The extended range is nice and all, but if somebody makes a car that can run the AC without running&#x2F;draining the battery while it&#x27;s parked, even if it&#x27;s just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it&#x27;s released here. Hell, I&#x27;d consider it even if it would just keep the fans on to vent the hot air out.<p>Parking in the sun while doing errands, which often involve multiple short trips where the car&#x27;s AC doesn&#x27;t get enough time to cool it down, seems to be a very common cause of heat-stroke among white-collar workers here. I&#x27;ve had to go to the ER twice about it this summer alone.

Does the math check out? You would need about 10kW-h to get the claimed distance, times three for the efficiency (by the way, there are NO mass-produced cells with 34% efficiency; they must be using GaAs or multijunction cells to achieve 34%) means solar input of 30kW-h per day. The projected horizontal area of a Prius is 8m^2 (including the windows) so we need about 4 hours of 1000W&#x2F;m^2 insolation. Which I guess isn&#x27;t totally impossible. Typical average insolation at populous latitudes is around 200W&#x2F;m^2.

They are claiming up to 27.7mi per day left in the sun. If true, my 5mi commute each way would be possible without ever charging the vehicle in the summer...<p>That being s said, curious how this holds up to weather (hail, snow, etc) and whether those numbers are accurate.

This is like any other concept car. It&#x27;s a cool concept but won&#x27;t make it to production.<p>The commercial viability of this is far off. 34% solar is prohibitively expensive. You won&#x27;t see these on cars until costs come down significantly.

They covered the car, including the back window, in triple-junction solar cells. Last I heard, those were made of expensive stuff like indium gallium arsenide junctions. They were popular on satellites because they do really really well outside of atmosphere and much worse in shaded and indirect light conditions than silicon.<p>I&#x27;d like to know how much those cells really cost and how much power is left when you can see out the back window again. 860W sounds like a high number. Fancy 30+% triple junction solar cells cost something like $200-$300 per _watt_ years ago. As a result, those solar panels might be worth more than the car itself! Even if they&#x27;ve got the fancy ones down to $50&#x2F;watt, that&#x27;s still $43000 in solar cells. Sure they&#x27;ve got grandiose claims about how little they&#x27;ll cost in the future, but I&#x27;d like to know about today.<p>This is same bunk as hearing they&#x27;ve made a new crazy high efficiency solar cell, but it can&#x27;t be manufactured outside a lab with a mountain of grad students doing the work. Sounds cool, but it won&#x27;t come to market any time soon.

See also: <a href="https:&#x2F;&#x2F;lightyear.one&#x2F;" rel="nofollow">https:&#x2F;&#x2F;lightyear.one&#x2F;</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_cities_by_sunshine_duration" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_cities_by_sunshine_dur...</a><p>Using those I found Lightyear quotes &quot;271 days of carefree range&quot; for Marsa Alam, Egypt. Interested if anyone finds a city with a higher quote

We used to fight for the shady parking spots.<p>Imagine the future when you fight for the sunny ones.

This is interesting because the solar strip on the Nissan Leaf SL was just a do hickey, 9 watts max. It was capable of trickle charging the 12V starter which meant less draw for charging the 12V coming from the traction battery. Not nothing but really not much. I don&#x27;t think it even rounded up to a mile of range.<p>I&#x27;m not sure what&#x27;s up with the visibility out the rear window of the Honda as pictured.

I once used an 85W portable solar panel to charge my battery while driving after the alternator failed.<p>It was surprisingly effective at keeping the car operable, at least until the sun went down. I didn&#x27;t have any accessories running, so it was just the ECU&#x2F;fuel pump&#x2F;injectors&#x2F;ignition it had to keep up with.<p>The experience left me wondering what MPG improvement it would be to embed solar cells in the trunk lid and hood for charging the battery in the daytime, offloading the alternator.

Triple junction GaAs based panels for a whole 860 watts of power in full sun at the right angle, no mention of cost.<p>Anybody know how much a panel like that goes for per watt now days?

Meanwhile I just discharged 12V battery of my hybrid toyota by sitting inside with phone plugged in and fans running.<p>There was no warning and now I have to fiddle with cables and second car to get my car to start. All while there&#x27;s still charge in hybrid batteries that I assume could trickle charge my 12V to help me start the car. But it won&#x27;t.

There&#x27;s also Sono Motors, a start-up from Munich, Germany. They aim at delivering something they call a SEV (Solar Electric Vehicle) in 2020. They have an interesting concept and more than 10k reservations. <a href="https:&#x2F;&#x2F;sonomotors.com&#x2F;?lang=en" rel="nofollow">https:&#x2F;&#x2F;sonomotors.com&#x2F;?lang=en</a>

I wonder if there is a market for a car cover that acts like a flexible solar blanket. Here in Texas it could offer your vehicle some protection from the Sun while charging it at the same time.

Always wanted this, makes a lot of sense in the desert. Is Toyota still turning on the headlights in the daytime? Seems like it would negate this advancement.

Without clicking, I was going to post a sarcastic comment about also putting battery on hood and trunk lid. Then I saw the picture. lol

The solar one of worked meant I do not have to charge the car for most of the trips I did!!! Shocking.

There’s no way it’ll charge while driving. It might discharge more slowly while driving and charge while parked.

If you run the math on this, even assuming 100% efficient conversion to electricity, it doesn&#x27;t seem very useful.

Who wrote this?<p>&quot;This demo car’s prototype cells can convert solar energy at 34% and up&quot;<p>34% what?<p>&quot;Using a redesigned solar battery cell film that measures only 0.03 mm&quot;<p>0.03mm wide? Long? And what&#x27;s a solar battery cell film???