Featured Toyota testing new solar powered Prius

Well what’s weird is if you end up putting 1kW solar on a vehicle, it ends up being a rolling PV supplier that you would want to hook up to. So you definitely want a plug on it not to just recharge the car when it’s cloudy out, but how about using some of that extra power when needed like power outages, camping, emergency services, etc..


Unsupervised!

 

Max?
A home in Japan might be limited to 100V 6amps for charging an EV. Many of the quirks with the Prius Prime is because it was designed for Japan. The solar roof option was to compensate for the limited charging an owner there may face.

 

Any form of hybrid in the future will be for the owners with limited home charging possibility, so a hybrid with solar makes more sense then BEV with solar to me. A BEV owner will have solar on his house.

 

then consider THE most efficient solar panels are around 350 Watts - perfect 60° weather & perfect 90° direction to the sun - & that's ONLY while FLAT panels are facing the Sun at a perpendicular angle - few minutes during the middle of a summer day somewhere near the equator. Long story short, with a solar panel's loss from a car's heat, or clouds, or poor sun azimuth due to varying seasons / lower sun azmyth earluer/later during every day? ... because no one lives on the equator at high altitude where it's reasonably cool anyway - one may be lucky to get ⅓ of that wattage on a good day for a few minutes of that perfect day ... presuming one doesn't park in protected areas , or under a shady tree, or cloudy day during that perfect hour of the day. Thwn the output gets worse after that. Never mind factoring in the curvature of panels on a car roof. Until panels get way more efficient, it's still just a gimmick, although it would be great if it was real.
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ok - since July to September roughly 60 days they've added about ½ mile a day, 35 miles. And counting the parked time, another ½mile/day for a grand total roughly a mile a day over some 60 odd days Driving 27mph .... using outrageously expensive aerospace-grade panels not available to the public due to extreme costs. The panels look bolted on to the various surfaces, including the rear windows, for the not so pleasing look, so that's going to dissuade a lot of prospective buyers. Like discussed earlier, maybe someday.
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We have no idea of the cost for the experimental solar Prime. The current PV roof option is $3000 in Japan. Since covering the rear window might make it illegal for road use, a factory version with these new PV panels will have less area.

 

Aha, that makes sense, sorry, was missing context.

Understanding that now, Toyota is the world leading auto manufacturer. I am surprised they have so much focus on their small home market to the detriment of other markets.
Lack of plug, makes sense in their home market (given the grid there). But for 90% of the world market, that doesn't make sense.

 

They are using much more expensive solar panels and say that it is a 860 watt panel (probably around 550 watts if made in standard form factor). Definitely will be degraded because of angle.

They took the ideal of 27.6 miles parked and 35 miles driving to say average. Its simply bad misleading reporting. EPA range for the prime is 25 miles on a 8.8 kwh pack. My guess is this is using jc08 reporting and assuming a 79% charging efficiciency can become 100% if the power goes directly to the motor instead of charging the battery then discharging. Assuming 6x of the 860 kwh panel (I got 4.75 x on my better angle roof mounted panels in Texas in august which is more than you will get in japan or most of the world on car mounted panels, more than I will get on average in the year) that is 5.16 kwh. Assuming you could do that every day (you can't) for 15 years its 28,270 kwh. Its not bad, but if you use epa's 133 mpge for the prime you get around 20 miles a day or 110K miles over 15 years on these semi ideal days. My guess is it would be less than 40 K miles unless you lived in a very sunny place and parked in nearly ideal conditions. That still is 800 gallons of gas @ 50 mpg, so its not bad, but it is far short of those idealized numbers.

There were also reports on how thin the cells are, which they really are, unfortunately to manufacture them on a car properly toyota is taking 1 cm, which seems about right. I'm sure in 10 years they can probably bring costs down and figure out how to mount them better. Still if the panel costs do really come down it will be less expensive to add charging stations and fixed solar, but there are places that make sense. For now we will see much less expensive technology like the 180 watt solar roof on the current Japanese prime, or the slightly more powerful one on the hyundai.

 

That $3000 only provides about 4 miles a day. I don't think you are spending that much to go just 1500 miles a year. With @austingreen numbers, a consumer system with these new PV cells will mean 7300 miles a year, but it will likely cost more.

Sounded like part of the thicker mounting was is to provide adequate cooling to the panel.

The current solar roof on the Prime supplies power to the 12volt accessories. Any measurement of how much it covers, and how that impacts fuel economy?
It has to be cost effective for the market. A hybrid already costs $3000 more. How many will pay double that for a much smaller increase in full economy?

 

AG your generosity is great
The highest price & greatest efficiency panels are still under 24% under normal conditions.
15 Most Efficient Solar Panels for your home in 2019?
So it'd be way over-kill enough, to imagine ultra efficient panels being 48% ... not to mention more than doubling the listed/linked sun power panel's expense.
Then in regards to 'August output' ....
Around here, our highest asmuth happens mid June. That month is actually cooler as well. Solar panels can easily lose 20% output as temperatures climb over the 90°f mark. A 90° day means 150° in the car. Conversely, if panels are sub 60°f, they will overproduce.
In the test tube environment - 79° efficiency CAN be reached, but it'd require a complex chilling system attached to the back of the panels so that they could create such a high output. I suppose that would be a source of heat exchanged - which could be used to warm batteries or passengers, but who can wrap their head around the cost of such a system. It's starting to sound like the hydrogen hoax.
Then .... putting
PV juice directly into motor use - rather than battery storage. That's another hurdle/cost, as one would have to invert to AC & come up with a stepped up Transformer .... & still convert it to 3-phase. We installed a rotary phase converting motor for a Bridgeport Mill in my dad's garage decades ago, & I recall it being rather costly.
Nothing wrong with a good science project, but it's misleading when these articles make claims as though they are just around the corner.
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I was being generous in the the overestimation of 6x the panels rated watts per day, we know that and it was stated. The sharp panels are multi junction not single junction. sharp multi junction panels have been demonstrated at 44% efficiency 6 years ago. They are ridiculously expensive. Toyota/sharp appears to be experimenting at 34% efficient panels, which I am sure are less expensive but much more than your sun power panels. Someone at NREL last year estimated about $300/watt for such panels, while I bought 330 watt LG 19.3% efficient panels in July for slightly less than $1/watt, $2.50/watt installed with labor, mounting hardware, inverter, sales tax before tax and utility credits. Definitely the toyota figures of 860 watts for the configuration covering a car are believable, and likely sharp/and toyota are spending less than the $25K for cells NREL estimated, but its going to be expensive today. Multijunction panels are mainly used for space applications where cost of launch dwarfs the costs of the cells, but say they get it down to $50/watt, I can see it having a lot more applications, and that may drive costs down quite a bit. I really don't know what volume is needed.

1) well yes with today's manufacturing they are going to be expensive. I doubt they require a chiller, but toyota needed to add to the process for cooling, but this is passive.

2) The LG panels I used are quite good at operating in the hot conditions my panels must live in. I used august numbers because that is max for my location (August is dry with few clouds blocking the sun) and I just got the roof turned on in mid july, so first full month. I am sure in your location you would get more power per year out of the same panels, but japan is not nearly as good as my location.

3) Yes this is a science experiment that toyota and sharp are running and is sponsored by NEDO which acts like a Japanese government agency. It is not nearly as far fetched as hydrogen. If sharp is able to bring down the price of these cells then there are quite a few uses. It will be interesting to see how much energy the panels actually collect. According to LA times, NEDO thinks it will probably be best for sunny places like california and western china, but they also want to test it in Tokyo.

Lightyear one and Sono Sion are both doing a different science experiment. They are using the best of available single junction solar cells but designing the car to have a large area about 5 square meters or 3x the size of a standard roof top solar panel. Lightyear one is producing an expensive luxury bev with that solar roof, and the team that won the solar challenge and a lot of other tallent trying to get 500 of them built and sold in 2021. Sono Sion is using the best sun power cells (24% efficiency the best sun power currently have for rooftop panels is 22.8% so this is probably partially still in the lab) to get 1.2 KW. My guess is lightyear one will be around the same. These cells are more expensive than the 19% efficient cells, but they are much more affordable than the multi junction cells. This is a european based (german headquarters, swedish manufacturing)crowd funded start up, so I have me doubts. They plan to start production of a 35.5 kwh inexpensive small family hatchback/wagon with a large solar roof in a previous saab factory now owned by a chinese corporation. I'd love it to work out, but odds are long against this business plan unless governments help out a lot.

 

Multi-junction panels. Wow! Talk about a scienrific Rubik's Cube ..... from what I can glean, these complex suckers have been in the works for over a ½ decade.


So, they blast it with all kinds of lab/science/spectrum light & work for a efficiency of 40%- 50%. Ok i get it. But for terrestrial use? Who knows, maybe someday.

 

Put micro antennas under the bottom layer and beyond 80% is possible

 

Previously I'd mentioned putting chilled water jackets - attached to the back side of panels. Keep them below 65°f & production goes way up. Only thing, is that there is a cost. It's seriously Eeeuuuge. Even so, there are a couple companies doing it, for residential use. You get hot water & electricity ... running over 50% efficieny - for what would otherwise be , simply waste Heat. Those cooling systems - as expensive as they are - are way cheaper than the products that the test tube Prius & NASA are playing with. K.I.S.S. ... but if the multi-layer panels ever do become cost-effective? And capture the heat from behind them? Wow, that would really be a win.
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The problem is that, for example, on my house I'm generating a few kwh while my panels sit in the hot sun for hours and hours.
The amount of cold water that I have that I need to heat up would only need to cycle through the panels and be done in maybe an hour. What would I do with all that other water?
I guess I could irrigate with hot water just for the sake of cooling the panels.
Might cause excess evaporation watering mid day, though.

Mike