Author Topic: Solar 'freakin' cars.  (Read 816 times)

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Offline The Soulman

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Solar 'freakin' cars.
« on: November 07, 2017, 08:52:22 PM »
Please debunk this one, almost ashamed being Dutch.

Quote
Effortless Energy

Lightyear One is charged by solar power. This unique quality allows it to drive for months without charging. You are sure to have peace of mind, knowing your electric car can always drive. The battery ensures that you can drive anywhere, even at night.

https://www.lightyear.one/
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Offline rob77

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Re: Solar 'freakin' cars.
« Reply #1 on: November 07, 2017, 09:07:27 PM »
one-seater made of 2 bicycle frames could be called a "car" and could be light enough to make it work  :-DD  :-DD  :-DD
 

Online NANDBlog

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Re: Solar 'freakin' cars.
« Reply #2 on: November 07, 2017, 09:13:35 PM »
What is there to debunk? You can charge a car with solar energy.
https://www.digitaltrends.com/cars/toyota-prius-prime-solar-roof/
It is about 5 km/day, in ideal conditions. If you cover more of the car, it will generate more. I guess if you cover the bonnet/hood (I hope both side of the ocean understands it) and the rear of the car, maybe you get 15km.

I have a solar panel on the top of my prius (3).
It was supposed to charge the HV battery, but the electronics generated too much EMC, so Toyota had the system removed. Instead, it runs the air conditioning system when the sun is shining.
But the car is definitely cooler if the system is turned on, on a hot belgian summer day (haha. hahahaha.).
 

Offline rob77

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Re: Solar 'freakin' cars.
« Reply #3 on: November 07, 2017, 09:42:09 PM »
What is there to debunk? You can charge a car with solar energy.

yes you can but to get the 10.000 to 20.000 km per year from solar (that's on their website) you have to have a very light vehicle with a big solar panel. so definitely not doable with a nowadays "standard" car. 
5km a day yields only  1825km and you have to have 365 sunny days per year for that :)
 

Online digsys

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Re: Solar 'freakin' cars.
« Reply #4 on: November 07, 2017, 10:04:30 PM »
NO debunking required !! (Facts / figures may be stretched, but I didn't read it yet). As part of the WSC, we recently completed the 30th anniversary of the
famous Darwin to Adelaide challenge ! This is the 3rd season of the road-legal "capable" category, and we had 14 teams already.
Some were a bit silly, not really functional, but each season, they are getting far better. For 100s of photos and videos, check either -
https://www.facebook.com/WorldSolarChallenge?fref=ts   Facebook or https://www.worldsolarchallenge.org/dashboard/map  main website
From there, you can follow links to dozens of Universities own pictures and technical info. I was very impressed with some of the entries, remembering that
most teams are made of students with ONLY their first season, a few may do 2 seasons before they finish Uni. The future is VERY BRIGHT :-)
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Online NANDBlog

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Re: Solar 'freakin' cars.
« Reply #5 on: November 07, 2017, 10:20:24 PM »
What is there to debunk? You can charge a car with solar energy.

yes you can but to get the 10.000 to 20.000 km per year from solar (that's on their website) you have to have a very light vehicle with a big solar panel. so definitely not doable with a nowadays "standard" car. 
5km a day yields only  1825km and you have to have 365 sunny days per year for that :)
Those are just numbers. They dont matter that much, because the bigger issue is to park your car in the direct sunlight. I park mine in a garage.
It is just another electric "supercar", overpriced, without service network, just with a gimmick feature. It's 120000EUR. For that amount, you can buy a Catherham 7 to have endless fun on the weekends, a Range Rover to go anywhere  and a Tesla 3 to be green, and install a 20kW solar on your roof, and have leftover for fuel for 100.000 km. Maybe one of these has to be a second hand one for the budget. That is the only number that matters.
 

Offline Old Don

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Re: Solar 'freakin' cars.
« Reply #6 on: November 07, 2017, 11:11:55 PM »
One more solar pipe dream, IMHO.  :--

Would be wonderful if we had the technology to do 10% of what is promised in cases like this. I'd be in line to buy if it were possible use a solar/battery electric car in real life in cold climates. For example, last week I drove 600 miles (one way) in a cold rain to visit with a very sick sister and then returned home a week later for about a total of about 1300 miles in a week. Crossed Pennsylvania driving up and down large hills with speed limit of 65 or 70 mph, heater on and wipers at times plus I was driving at night for part of the trip. I don't think a solar car would have had a chance to recharge along the way during 15 - 30 minute rest stops. But that's not even the worst example, I keep asking the electric car fans what would be the range of an all electric car parked outside overnight mid-winter in Fargo, N. Dakota at -40 deg's (that number is the same for both F or C) with seat heaters, defrost and interior heating turned on plus knowing that battery packs will be suffering from the cold temperatures. A gasoline car requires AC powered electric block heaters to prevent engine freeze ups and to allow oil to remain viscous so it can be started and so it too uses electricity in that environment. Truly hostile to any vehicle.

Maybe in Southern Europe you could drive a "solar" battery typical small car 5 or 10 miles (15Km?) and return to a garage with a charger. If you then could park the car in direct sun for 8-10 hours and return home on battery. But even there with pure solar, not even close IMHO - no go. Today, it might be possible to run one of those college built light weight solar vehicles (hate to call them a car) for a few hundred klicks in the bright light deserts of the world, but not even those things in the far north/south parts of the world in winter. I'd like to see one in Alaska or Sweden with no solar energy for months.
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Online digsys

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Re: Solar 'freakin' cars.
« Reply #7 on: November 08, 2017, 12:24:21 AM »
Yeah, you're right. Because we can't solve ALL the worlds problems in short time, there's no point wasting any effort on it. Good point. Lets all give up.
And you're right again, most people keep their cars locked in a garage and never drive them during the day ... all that wasted effort ... all  those poor 1'000s
of Uni students time wasted .... but then ..
In the last 30 yrs, several designs (some major) have been snapped up from WSC development teams and gone to Electric  vehicle / solar power systems.
The cars themselves are NOT final production-ready, they prove a technology. Like our 98.5% wheel motors, low loss tyres, cell encapsulation etc etc
Design criteria include - the car must maintain 50-70Km/hr from sunlight only ... but there's no point because they don't work in -100C, at night, up mountains ... sad :-)
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Offline The Soulman

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Re: Solar 'freakin' cars.
« Reply #8 on: November 08, 2017, 08:04:10 AM »
Some context, I had to sit thru a longgg lecture from a (non technical) guy who is a ted-x speaker and teacher at MIT  :-//.
He was shamelessly promoting this vehicle in front of a large equally (slim to none) technically educated audience, and making even bolder statements
than the lightyear website, and the audience fully accepted it as fact.  :palm:

Yes it is good to push the technology on these type of cars as we sure need them in the future, but making claims that only a over-unity device could realize is imho pure BS, and will only deceive people, not ok.
No point in making a point just to make a point, that would be pointless.
 

Offline Old Don

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Re: Solar 'freakin' cars.
« Reply #9 on: November 08, 2017, 08:11:51 AM »
Lighten up, people do still have the right to disagree on technical issues. Here's a link to a solar car in Buffalo, NY:   https://corysthoughts.wordpress.com/2014/11/20/blizzard-blankets-buffalo-in-pictures/   :-DD  On second thought, maybe I could just add a windmill to a solar car so that it will charge the battery as I drive it in winter, do note I once thought about joining the church of Our Lady of Perpetual Motion, but I found out that my friend, the high priest, was an self-taught engineer.  :-//   :phew: :palm: :horse: >:D >:D  :-+

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Offline CatalinaWOW

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Re: Solar 'freakin' cars.
« Reply #10 on: November 08, 2017, 09:25:19 AM »
Yeah the problem is the non-technical people playing telephone with the information.  It is much like bicycle speed records and human powered flight. 

A few decades ago a friend of mine led a team which became the first to design an build a bicycle that could maintain 60 mph on a level course with no draft vehicle.  Required a world class athlete to achieve the number.  Press articles referred to people riding bicycles on the freeways and keeping up with traffic.  Possible only for that world class athlete and even that was for short distances.  Might make it to the next exit.

Same thing occurred as human power flight was first demonstrated.  Again, world class athletes demonstrated short flights under controlled conditions.  The press translated this to people pedaling around the air like bicycle paths.  Although the human flight record has since been extended clear across the English channel it remains a stunt rather than something that available for the average young athlete, and definitely not for the average citizen.

Solar powered vehicles are possible, but the basic physics mean they will have a limited daily energy budget and will have to choose wisely between payload, speed and endurance.  They can hit some impressive numbers on one or the other of these in good climactic conditions, but will never hit high marks on all three at once.  A specialty market forever, though more realistic that human powered commuter planes or freeway bicycles.
 
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Offline Someone

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Re: Solar 'freakin' cars.
« Reply #11 on: November 08, 2017, 11:18:59 AM »
You can see where the team is coming from with their previous vehicles:
http://www.dailymail.co.uk/sciencetech/article-3151506/The-future-school-run-Four-seater-family-car-powered-sun.html
There aren't any wild claims on the FAQ of their official site:
https://www.lightyear.one/i-want-one/
It looks like they're planning a very lightweight vehicle evolving from their previous work thats entirely plausible, it likely wont be a high performance super car but a practical 4 seater vehicle with the entire top surface covered in solar panels. As a plug in electric with the battery range they're hoping to achieve its already a practical vehicle before considering the solar cells, the solar parts might make it more expensive and lower performance but they push back against range anxiety.
What is there to debunk? You can charge a car with solar energy.
https://www.digitaltrends.com/cars/toyota-prius-prime-solar-roof/
It is about 5 km/day, in ideal conditions. If you cover more of the car, it will generate more. I guess if you cover the bonnet/hood (I hope both side of the ocean understands it) and the rear of the car, maybe you get 15km.
Those numbers add up when you're stuck with an existing car shape/platform/weight and doing a typical 30-40kWh per 100km but if you change to a lightweight and streamlined vehicle like they are proposing you can take that down further by a factor of 2 or more easily. Even without that, only increase the solar panel area to 5m2 for 10kWh a day and you've already hit their advertised numbers of 10 thousand km per year from solar power alone.
10kWh/day * 365 days = 3,600kWh
3,600kWh/(30kWh/100km) = 12,000km/year
It's all all within the claims they're making on their website.
« Last Edit: November 08, 2017, 05:49:37 PM by Someone »
 

Offline glarsson

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Re: Solar 'freakin' cars.
« Reply #12 on: November 08, 2017, 04:33:05 PM »
Those numbers add up when you're stuck with an existing car shape/platform/weight and doing a typical 30-40kWh per 100km but if you change to a lightweight and streamlined vehicle like they are proposing you can take that down further by a fact of 2 or more easily.
But will such a lightweight vehicle be able to pass crash tests? Current vehicles are not shaped the way they are or built heavy without reason.
 

Offline Someone

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Re: Solar 'freakin' cars.
« Reply #13 on: November 08, 2017, 05:55:58 PM »
Those numbers add up when you're stuck with an existing car shape/platform/weight and doing a typical 30-40kWh per 100km but if you change to a lightweight and streamlined vehicle like they are proposing you can take that down further by a fact of 2 or more easily.
But will such a lightweight vehicle be able to pass crash tests? Current vehicles are not shaped the way they are or built heavy without reason.
A lot of weight goes into comfort/feel/robustness of modern vehicles, you can cut back on a lot before eating into safety. The current homogenous look of new cars is a combination of lowest common denominator features to meet worldwide standards, public acceptance for mass market products, and a car industry rapidly consolidating its platform/parts diversity. A small startup can ignore most of that for a niche market inside a limited geographic region. But its true that homologation (compliance) is going to be the majority of the work for a new entrant to the car market and they will spend a lot of time and effort to try and meet it.
 

Offline Daixiwen

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Re: Solar 'freakin' cars.
« Reply #14 on: November 08, 2017, 07:36:39 PM »
Those are just numbers. They dont matter that much, because the bigger issue is to park your car in the direct sunlight. I park mine in a garage.
Just keep the garage lights on. Where is the problem?
 
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Online digsys

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Re: Solar 'freakin' cars.
« Reply #15 on: November 08, 2017, 08:24:07 PM »
Quote from: glarsson
But will such a lightweight vehicle be able to pass crash tests? Current vehicles are not shaped the way they are or built heavy without reason.
All cars in the new cruiser class must pass at minimum, ICV tests. Crash tests / rollover and all MAIN safety ones.
Quote from: Someone
A lot of weight goes into comfort/feel/robustness of modern vehicles, you can cut back on a lot before eating into safety. The current homogenous look of new cars is a combination of lowest common denominator features to meet worldwide standards, public acceptance for mass market products, and a car industry rapidly consolidating its platform/parts diversity. A small startup can ignore most of that for a niche market inside a limited geographic region. But its true that homologation (compliance) is going to be the majority of the work for a new entrant to the car market and they will spend a lot of time and effort to try and meet it.
Absolutely agreed. NOT all EVs / Solar need to be so over-designed / overpowered like the TESLAs. I applaud Tesla for really bringing EVs onto the world stage,
and his many ventures are definitely going to speed up EV / battery development that we would never have seen, but he is also a niche.
So are we in the west, for now :-)
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Online NANDBlog

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Re: Solar 'freakin' cars.
« Reply #16 on: November 08, 2017, 08:30:08 PM »
Those are just numbers. They dont matter that much, because the bigger issue is to park your car in the direct sunlight. I park mine in a garage.
Just keep the garage lights on. Where is the problem?
Wireless charging! I bet you could get a few million dollars from morons, lie those who funded uBeam.

You can see where the team is coming from with their previous vehicles:
Those numbers add up when you're stuck with an existing car shape/platform/weight and doing a typical 30-40kWh per 100km but if you change to a lightweight and streamlined vehicle like they are proposing you can take that down further by a factor of 2 or more easily. Even without that, only increase the solar panel area to 5m2 for 10kWh a day and you've already hit their advertised numbers of 10 thousand km per year from solar power alone.
10kWh/day * 365 days = 3,600kWh
3,600kWh/(30kWh/100km) = 12,000km/year
It's all all within the claims they're making on their website.
The prius has .25 drag factor. No production car had 2x the improvement over this. It is impossible without looking like those aerodynamic bicycles driven by those crazy people.

The P100 package for the model S has 500km range, this claims 800km. The battery alone would weight 700-1000kg. You cannot just magically improve something by the factor of two.

This would require a 2x better efficiency solar panel, 2x better battery, 2x lighter car. They are stretching the truth. And then you end up with a car, which probably has -5 stars on the Euro NCAP (the first thing I check on a car).
 
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Offline Ice-Tea

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Re: Solar 'freakin' cars.
« Reply #17 on: November 08, 2017, 08:36:03 PM »
Checked their 'team'?

Pretty much most of them are fresh out of school. Or still in school. The CEO graduated, well, now.
An engineer never has a problem. He just needs more time.

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Offline Old Don

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Re: Solar 'freakin' cars.
« Reply #18 on: November 09, 2017, 02:05:54 AM »
There's still plenty of life left in the internal combustion engine and emissions are at near zero today. Like it or not the power density of gasoline is hard to replace.

Some years ago we were involved with an experimental nearly-all plastic engine. The idea was that for every 100 lbs removed from the drive train an extra 100 lbs could be removed from the rest of the car (small tires, lighter support structure etc) and still have a 4 passenger sedan. A 4 cylinder race engine based upon the 4 cyl Pinto engine and later a 6 cyl engine that was raced a few times. The limiting factor was the hand-made engine block, while the injection molded Amoco Torlon parts could have been mass-produced, IMHO.

See Polimotor: https://en.wikipedia.org/wiki/Plastic_automotive_engine   plus:  http://www.buildagyrocopter.com/once-there-was-the-plastic-engine-polimotor/

Youtube:    plus   
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Offline Someone

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Re: Solar 'freakin' cars.
« Reply #19 on: November 09, 2017, 11:51:30 AM »
You can see where the team is coming from with their previous vehicles:
Those numbers add up when you're stuck with an existing car shape/platform/weight and doing a typical 30-40kWh per 100km but if you change to a lightweight and streamlined vehicle like they are proposing you can take that down further by a factor of 2 or more easily. Even without that, only increase the solar panel area to 5m2 for 10kWh a day and you've already hit their advertised numbers of 10 thousand km per year from solar power alone.
10kWh/day * 365 days = 3,600kWh
3,600kWh/(30kWh/100km) = 12,000km/year
It's all all within the claims they're making on their website.
The prius has .25 drag factor. No production car had 2x the improvement over this. It is impossible without looking like those aerodynamic bicycles driven by those crazy people.
Factor of 2 in frontal area much easier to achieve, so you're jumping to the most difficult ways to achieve the end result and ignoring the low hanging fruit. Also note that the Prius is not the lowest Cd or even CdA in a production car so they can be improved upon, the Prius isn't even the most fuel efficient of vehicles overall so we know that there are already solutions out there. Yes it will likely be a radical departure from other vehicles and have a very low lying seating position, so do sports cars but with other end goals in mind.

The P100 package for the model S has 500km range, this claims 800km. The battery alone would weight 700-1000kg. You cannot just magically improve something by the factor of two.
The range figure is not quoted against any specific test cycle, its believable that an 800km range is possible with your suggested 1000kg or so of batteries. This is still well below the diminishing returns where adding more batteries to increase range adds smaller and smaller amounts and asymptotes. A battery option that has such a large range is exactly where we would expect it to be and in no way challenging. The factor of 2 in just energy use per 100km makes the batteries go further and hits the expected figures, its not needing multiple factors of 2 throughout the system to do what they claim and everything adds up (even the price is plausible)

This would require a 2x better efficiency solar panel, 2x better battery, 2x lighter car. They are stretching the truth. And then you end up with a car, which probably has -5 stars on the Euro NCAP (the first thing I check on a car).
Nowhere is anyone suggesting doubling the efficiency of solar cells is necessary to make this work, just you and some more straw man arguments. All it requires is 2x less energy consumption per distance travelled, and more area of solar panels. Thats it, all possible, and all easy to engineer with todays technology.
 

Online NANDBlog

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Re: Solar 'freakin' cars.
« Reply #20 on: November 09, 2017, 08:20:04 PM »
Ok, so you need to reduce the rolling resistance by a factor of two. If a 4 seat car.
It is also lightweight, with a metric ton of battery. And you also need to reduce the rolling resistance by a factor of two.
And of course, this will be done by a dozen dutch graduates.
For a production car.
With their own design.
Thats it, all possible, and all easy to engineer with todays technology.
It is anything but easy.
I've seen larger engineering teams working on electric car BTW. It looked like this:
« Last Edit: November 09, 2017, 08:41:06 PM by NANDBlog »
 

Offline rob77

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Re: Solar 'freakin' cars.
« Reply #21 on: November 11, 2017, 04:57:54 AM »
All it requires is 2x less energy consumption per distance travelled, and more area of solar panels. Thats it, all possible, and all easy to engineer with todays technology.

and exactly that's NOT doable ;)
if the 2x less energy consumption was doable then tesla and the others would have done it already. and obviously there is a finite usable surface on a car, so where exactly would you put the extra panels ?
 

Offline Someone

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Re: Solar 'freakin' cars.
« Reply #22 on: November 11, 2017, 09:12:52 AM »
All it requires is 2x less energy consumption per distance travelled, and more area of solar panels. Thats it, all possible, and all easy to engineer with todays technology.

and exactly that's NOT doable ;)
if the 2x less energy consumption was doable then tesla and the others would have done it already. and obviously there is a finite usable surface on a car, so where exactly would you put the extra panels ?
Again taking examples of traditional cars that aren't state of the art aerodynamically, back through the history of cars there have been many vehicles with reduced frontal area and low Cd figures (https://en.wikipedia.org/wiki/Automobile_drag_coefficient) in recent history we have things like the EV1 and XL1 (CdA 0.37m2 and 0.28m2 respectively). But just look at the existing cars the team has worked on, its already been done by them. I presented the links for those who are too lazy to research for themselves:
You can see where the team is coming from with their previous vehicles:
http://www.dailymail.co.uk/sciencetech/article-3151506/The-future-school-run-Four-seater-family-car-powered-sun.html
There aren't any wild claims on the FAQ of their official site:
https://www.lightyear.one/i-want-one/
It looks like they're planning a very lightweight vehicle evolving from their previous work thats entirely plausible, it likely wont be a high performance super car but a practical 4 seater vehicle with the entire top surface covered in solar panels. As a plug in electric with the battery range they're hoping to achieve its already a practical vehicle before considering the solar cells, the solar parts might make it more expensive and lower performance but they push back against range anxiety.
Tesla build a vehicle that looks and works like a traditional car, so of course it has efficiencies like a regular car. Once you step outside the upright seating and cabin large enough for obese people then its easy to make such large changes to the aerodynamics. A typical c-segment car has a footprint of 6-8m2 horizontal so there is plenty of space for the quantity of solar panels they are needing to get their figures. Perhaps you could come up with some numbers and examples of how its impossible? I've already presented some very simple examples that show they're claiming exactly what we expected they can achieve.
 
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