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Discussion Starter #1
I firstly want to state that the look of this car is a beautiful design compared to many current cheese box looking cars. For once we have a design that looks sporty but can still be green.

My desire for this car is to maximize its use. With advanced batteries, plugging in at night will provide a less expensive means of transport. However, it will be a long time before employers provide a plug in capability during the day. For many areas of the country the sun beats down all day long on the roof, trunk and hood of the car. These surfaces would be great places to put solar panels to trickle charge the battery during the day. Done with the right design you might not even realize they were solar panels. It might be enough to drive back home with having to use the combustion engine. If we are going to go green with a car like this lets really go green.

IWBG
 

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Assuming that there is 50 sq ft available surface for capturing the sun's rays. I figured it would add 7 miles of driving if the PV is at 15% efficiency.
 

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Solar Reply

Joereal,

Thanks for the reply. I bow to your knowledge on the subject. I guess I have a lot to learn yet. Even if you are over generous in your calculation, even if 5 additional miles are good, would it justify doing this if 5 miles every day for a week would payback the cost of putting these solar cells on the upper surfaces.

I survived both the 74 & 79 gas lines and I am hoping that this car will be out before we reach the next gas lines which I am sure is coming now that we have reach the $4+ per gallion rate. I believe this is only the tip of the iceberg. I would not be surprise by $7 next year this time.

IWBG
 

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Probably it would not justify the cost of solar. I'm having a hard time myself justifying the one for our roof tiles!

Until those Nanosolar or Solyndra thin film solar panels would materialize at retail for less than $2.62 per watt, then that would be the day. Right now it would be between $7 to $15/watt installed on car roof, the value of the electricity it will produce will not be enough to cover the finance charges and payments of additional investments.

But, the lowering of prices of solar PV panels are coming down, hopefully in 3 to 5 years, by then, it could be an option for the Volt for those in the sunny states like California.
 

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Discussion Starter #5
JoeReal,

Thanks for the input.
I guess this means I should hold off for awhile about those solar roof shingles.

IWBG
 

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JoeReal,

Thanks for the input.
I guess this means I should hold off for awhile about those solar roof shingles.

IWBG
As Texas would point out, be patient... Soon solar PV on the roof will be within most people's affordability.

Now, if I do the installation myself and not counting the cost of my labor, it is feasible. But have to postpone the project because of the projected decrease of solar PV Panels within 2 to 3 years, perhaps in time for the Volt.
 

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The Math

Joe, thanks for the info on what a typical solar auto install might accomplish. If the auto makers built it in............. it should cost a little less.......... Can you please take the time to show us the calc, take us through the math on the solar charge and what a proposed VOLT would use ? I think it would go a long way to illustrate how solar does and does not work.

Thanks !!! :)
 

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Joe, thanks for the info on what a typical solar auto install might accomplish. If the auto makers built it in............. it should cost a little less.......... Can you please take the time to show us the calc, take us through the math on the solar charge and what a proposed VOLT would use ? I think it would go a long way to illustrate how solar does and does not work.

Thanks !!! :)
Here's a straightforward typical calc, and remember, it all depends on assumptions, so you can modify the calcs to suit your needs:

Area (m2) x Solar Radiation (kW/m2) x PV efficiency x Equivalent perpendicular Sunshine Hours x Charging Efficiency x miles/kWHrs


Here's my assumptions:
Area of solar panels installed: 50 sq ft = 4.645 m2 (there's 0.09290304 m2/ft2). I don't have exact dimension of the volt and how much area can be practically covered with solar panels. It could be more or or could be less than 50 sq ft, which is of course 10' long by 5' wide. The actual surface area of the car could be more than this but the horizontally projected available area is just assumed to be 50 sq ft, perhaps the top roof, hood, and rear trunk mainly, assuming the rear is not shaded out by the roof when parked.

Solar Radiation at perpendicular solar radiation interception at ground level, we get about average of 982 W/m2, but this depends where you are, latitude, dust, smog and other particulate matter, day of the year and so on. Many solar PV company assume this to be 1000 W/m2 for simplicity of calculation. I used 982 W/m2 average value of solar energy.

Maximum solar PV efficiency of thin film solar panel is now reaching 15%. Nanosloar's thin film is about 14% after commercial scale manufacturing. Assume that thin film is used at 15%, let us be generous here.

If you multiply the first three terms above, you get the term called the Peak KW capacity of your installed panels. Some solar PV calcs make this process more complicated by using various terms. Some consider only the net area of the working cells, other consider all the area occupied by the system, counting up to the non-generating edges of solar panels.

Since it is impractical to tilt the Volt so that the panels are always perpendicular to the sun's rays, we just assume an average equivalent value of the sun shining from low angle in the morning to high at noon then to low angle during the afternoon striking a stationary parked Volt. You will have to obtain the average equivalent perpendicular sunshine hours for the whole day for your area. You can factor in cloudiness and come up with a yearly average (this data is published by most solar PV companies). I assumed average of 4.7 hours/day of equivalent perpendicular sunshine exposure.

The Charging efficiency can be complicated. Existing solar panels are designed to work with inverters that convert DC to AC and then the Volt recharger will convert that AC to DC for recharging. A direct method of DC to DC charging would be more efficient. As it is, the solar PV inverters are between 70 to 85% efficient, while the AC to DC charging of the Volt is about 90% efficient. So the overall efficiency could be 63% to 76%. But if DC to DC charging would be implemented from solar PV to Volt Battery, charging efficiency would have been 90% or more. I assumed 63% for my calcs.

The miles/kWH depends on your driving profile. The high values reported of the Volt's 40 mile range is from draining the 16 kWH battery from 80% to 30% charge, so an equivalent of 8 kWH for 40 miles. If you drive typically 70 mph, that would just give you about 28 miles per 8 kWH drain, I used the driving profile of 28 miles/8 kWH, that gives 3.5 miles/kWH.

So multiply all the terms together:
4.645 m2 x 0.982 kW/m2 x 15% x 4.7 hrs x 63% x 3.5 miles/kWH = 7 miles per whole day of parking in the sun.


Whereas, if you assume that based on your driving profile, the Volt goes 5 miles/kWH, and your area receives perpendicular sunshine equivalent of 6.2 hours during the summer, and if direct DC to DC charging is available as an option then we could get a value as high as this.

4.645 m2 x 0.982 kW/m2 x 15% x 6.2 hrs x 95% x 5 miles/kWH = 20 miles per whole day parking during the summer. That is half of the range of the Volt.

If the solar PV would have achieved the new theoretical efficiency of 70%, then we would have more than enough energy for recharging and then have some left over to give back to the grid. We will be achieving this long before we can visit extrasolar planets.
 

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But..... why waste money on a solar panel for the car when you can use that same solar panel on the house and not have any of the solar energy wasted. Any time the battery is charged and the car is in the sunlight that is electricity the volt is doing nothing with. Had it been on your house the energy could be put to good use all the time.

And I don't think you are likely to get more than about 2 miles extra per day while coving practical areas of the car with solar cells.

I think this solar power supplement is a long ways of before it is cost effective.
 

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Discussion Starter #12
First of all let me thank JoeReal for such an eloquent and well thought out explanation of the solar power calculation. Even a non-technical like me was able to follow it easily.

The reason I even asked about the solar panels was we have car surface that does nothing but be required to be washed and waxed and yes look good, but we are talking about an electric car sitting in the sun all day and why not make use of that. Yes we can plug our car into the grid at night, which might even been powered off the solar panels on the house roof, but we don't take the roof with us during the day but our car does just sit in the sun while parked at work.

So maybe it is not economically feasible to do solar panels on the car if only 7-20 miles extra is gained, but my personal believe is unless it is going to add another 5K to the price it might be something worth looking into.

IWBG
 

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Thanks IWBG. I for one am hopeful that the prices of solar panels will come down. It might be near... I own two houses that begged to be covered with solar PV when the price is right. I'm keeping track of the prices at retail. Perhaps will post it here when the prices reached break-even at the retail consumer level.
 

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Solar Cabin Ventilation

A solar panel integrated into the roof of the vehicle will charge the battery when the car is in the sunlight and power cabin ventilation of the parked vehicle.

That sunlight which now heats the interior of a parked car on a hot day will be captured as electrical energy and stored in the car's battery for future use or used to ventilate the cabin to keep it at ambient temperature. Hey, maybe that would save lives of kids and pets left in the car on a hot day?
 

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Folks, there are so many new functions that SOTS (Solar on the Surface) make possible. From temperature control, advanced vehicle situation management, security, battery maintenance to Always On Internet connectivity. Having the ability to accept energy while the car is sitting for long periods of time (airport parking lot, long Texas day in a parking lot, etc.) can add some new possibilities that even today’s cars can't imagine. Sure you might even get around 6 extra miles of range (in that long Texas day) but it's the other stuff that will really bring value to many car owners. Think of this. A normal car sitting in traffic on a hot sunny day is just belching out noxious fumes and wasting energy while the SOTS car is silently gaining energy and using it to keep the person cool. It's a total paradigm shift that most people cannot even comprehend!

Sure it's very expensive right now and will only be available to crazy solar fans like myself through aftermarket or factory installed options. Hey, to me it worth the value! You can have your 20 CD changer and leather seats... I'll have SOTS! Please people, don't marginalize the benefits of SOTS to a simple financial calculation unless you feel all car purchases and options are also made based only on cost. If that were true I think we would see a lot more Geo Metros around. Don’t you?

Anyway, we have talked this topic to death in other threads. There are calculations, beautiful pictures of SOTS boats and even a SOTS Prius. Just use the search button at the top of this screen and enjoy. Be careful, solar technology is additive. Something about the meter running backwards always seems to put a smile on peoples faces. At this very moment the sun is providing the earth with over 800 TW of energy (Humans only use about 15 TW)! No other energy source is even close. The sun is the solution, stupid. ;)
 

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Roof Photovoltaic Panels on an EV

Installing even the latest photovoltaic panels on the roof of the Volt would be like trying to fill a swimming pool from wringing a sponge full of water... Only a tiny amount of "juice" can be delivered to a very large hole in the ground.

A sponge can only soak up a small amount of water and current electric vehicles need a lot of high capacity charging in order to top-off the batteries. The delivery (charge) needs to be done in bulk, not in a trickle.

Also, in order to really get economy in charging a Volt (or any electric car) 110 volt plug-in isn't nearly as effective as using a 220 source. You can charge an electric vehicle less expensively with a 220 source than you can a 110 source. It's almost like trying to cool your house with window mounted air conditioners running off of 110 volts... (your electric company gets rich, if you DO cool an entire house with window units) but they will get less rich if you have a 220 system cooling your house. Or to put it into an analogy that we all can relate to, "buying in bulk" ... like a giant box of cereal at Sam's Club or Costco is cheaper than buying a small box of cereal at the convenience store.

Solar panels that could fit on the roof of a car just won't deliver the juice to really do much good. Maybe in 10 or 20 years, the technology will improve.

Ironically, I do have a flexible solar panel that I had intended to install on an experimental 2 seater airplane I am building (to trickle charge the battery, so I can talk on a hand-held NavCom) but solar charging needs to be done in bulk, by LOTS OF BIG solar panels in order to really do any good.
 

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Installing even the latest photovoltaic panels on the roof of the Volt would be like trying to fill a swimming pool from wringing a sponge full of water... Only a tiny amount of "juice" can be delivered to a very large hole in the ground.


Now that's just an idiotic statement! If you use the latest PV cells you can run one of those solar racers across the country. When was the last time you checked out solar cells, 1970?


A sponge can only soak up a small amount of water and current electric vehicles need a lot of high capacity charging in order to top-off the batteries. The delivery (charge) needs to be done in bulk, not in a trickle.

Also, in order to really get economy in charging a Volt (or any electric car) 110 volt plug-in isn't nearly as effective as using a 220 source. You can charge an electric vehicle less expensively with a 220 source than you can a 110 source. It's almost like trying to cool your house with window mounted air conditioners running off of 110 volts... (your electric company gets rich, if you DO cool an entire house with window units) but they will get less rich if you have a 220 system cooling your house. Or to put it into an analogy that we all can relate to, "buying in bulk" ... like a giant box of cereal at Sam's Club or Costco is cheaper than buying a small box of cereal at the convenience store.

Unfortunately, you are seriously confused about energy, power, efficiency, etc. I don't see any real calculations on your part so I'm guessing you don't have a clue. No offense.



Solar panels that could fit on the roof of a car just won't deliver the juice to really do much good. Maybe in 10 or 20 years, the technology will improve.

You fail to define "do much good". It might not fit your needs but it fits my needs perfectly. I believe there will be a big enough market for the functionality that I laid out in my post above. You see no value in those functions at all? That's kind of short-sighted for someone who is working with experimental aircraft. Again, it might be of value to one person (I for one see very exciting new possibilities) and nothing to you. There have been several EVs with solar roofs so I'm guessing many designers would agree with me (Aptera, GM, Saab, etc.). There only has to be a big enough market to support such options. You don't like it? Don't check the option box.


Oh, and look how sweet it can look...



 

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Unfortunately, you are seriously confused about energy, power, efficiency, etc. I don't see any real calculations on your part so I'm guessing you don't have a clue. No offense.

Unfortunately, you are in lala land. Solar panels on a Volt! The average consumer is thinking at $40,000 the Volt is going to cost them about a 1/3 of what the average house in the USA cost. Add solar panels to the Volt, and not many consumers will be opting for this add-on. GM isn't interested in making add-ons for the fringe element (maybe funky/trendy after-market shops in California) but not GM in Detroit.

I have two degrees. What is your degree in? Are you an electrical engineer? No offense!

I worked for an electric company, promoted solar technology produced at our solar farm in West Texas, as well as our Zond wind turbines... Solar panels on top of a car (the size of a Volt) won't contribute any serious energy to make them marketable to consumers. You could park a Volt in El Paso all day in July and the amount of mileage gleaned from that exposure wouldn't take you to the grocery store and your dry cleaner and back. Worse, that same Volt sitting outside in November to February exposure (when the sun isn't out very long) gets you even less of a charge. You are willing to spend the $$$$$$ to have a trendy solar panel on your Volt? I'd rather buy my kilowatts at 9.5 cents from my electric company to charge my Volt. I'll be driving a lot further than you will on that investment than someone shelling out $$$$ for solar panels on top of a Volt.

Prior to working for the electric company (with the largest chunk of real-estate in Texas) I worked for the El Paso Company (largest natural gas transmission company in the USA) so please don't suggest I don't know anything about energy.

My company car at the electric company (one of 2 I vehicles I drove in my job) was a $200,000 Dodge electric van. When I was a young tyke, my father made my very first car, powered by an electric motor... I drove it for several years. I think I have more experience in owning and driving pure electric vehicles than you. And yes, I may be an old fart, but I know the economies are not yet practical for ANY car company to market a vehicle with EXPENSIVE solar panels as an option. Maybe Bill Gates could afford one, and you would be willing to bleed your bank account (or credit card) for solar panels on your Volt, but for the vast majority of consumers, we have to look at the practical ECONOMICS of how a Volt is re-charged.

Furthermore, most of the people I know living in these sun-drenched regions of the Southwest, park their cars in a garage or covered parking (except maybe when shopping)... So at this juncture, putting solar panels on the roof of a car isn't an attractive option to the consumer OR the company making the car. At 9.5 cents per kilowatt hour, you can buy a hell of a lot of electrons compared to the cost of making a car that really has some serious potential for being SERIOUSLY charged by the sun. Putting a large array of solar panels on the roof of my house seems a lot more attractive to me for charging a Volt. The fringe element (zealots) probably would be happy to pay through the nose for a solar panel on the roof of their Volt, but the economies ARE NOT THERE at this point in time or the foreseeable future FOR THE AVERAGE PERSON who would be willing to switch from a gasoline car. YOU ARE NOT AN AVERAGE PERSON. I think you are a zealot (or beyond.)

Wind turbines and solar farms making electricity for the grid is a great option as I would be interested for charging my Volt, but YOU WILL NOT SEE people driving PRODUCTION EV CARS with solar panels on the roof, hood and trunk for a decade or more :)rolleyes:give me a break!:rolleyes:)

You fail to define "do much good". It might not fit your needs but it fits my needs perfectly. I believe there will be a big enough market for the functionality that I laid out in my post above. You see no value in those functions at all? That's kind of short-sighted for someone who is working with experimental aircraft. Again, it might be of value to one person (I for one see very exciting new possibilities) and nothing to you. There have been several EVs with solar roofs so I'm guessing many designers would agree with me (Aptera, GM, Saab, etc.). There only has to be a big enough market to support such options. You don't like it? Don't check the option box.

In regard to the airplane, my flexible solar panel is to aid in keeping a battery topped-off in a small hand held radio... My engine has magnetos (do you know the principle of a magneto?) and my engine does not have an alternator or generator...

[/QUOTE]

 

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But..... why waste money on a solar panel for the car when you can use that same solar panel on the house and not have any of the solar energy wasted. Any time the battery is charged and the car is in the sunlight that is electricity the volt is doing nothing with. Had it been on your house the energy could be put to good use all the time.

And I don't think you are likely to get more than about 2 miles extra per day while coving practical areas of the car with solar cells.

I think this solar power supplement is a long ways of before it is cost effective.
This is exactly my point. I (and I think everyone else, but the foolish) would rather invest thousands of dollars in solar panels for the roof of my house, not my car. When not driving my Volt, I want that investment doing some good for my electric bill. Further, I don't drive my car every day (not everybody parks their car for days at a time and I keep all 5 of my vehicles in a garage WHERE THE SUN DOESN'T SHINE, and the solar panels won't do any good IF ON THE ROOF OF THE CAR.) If I invest in solar panels on my roof (and airplane hangers in my back yard) I could effectively charge several electric cars AND MY BLACK & DECKER rechargeable lawn mower. Why spend the money to put solar panels on a Volt? Doesn't make a lot of economical sense to me. Putting them on the house is brilliant, and you can sell the excess back to your electric company. Electric meters can run backwards... thus it's almost like money in the bank.

ANOTHER BENEFIT... by putting solar panels on the roof of your house, it actually decreases the heat loading inside the attic space of the home. Less thermal energy is transfered (from roof shingle to decking to interior) when solar panels are on the roof of a house. Solar panels (most of the ones I have researched) are also highly resistant to hail storms... shingle roofs don't hold up very well and as a result, most home-owner insurance policies are less expensive (and reflected in lower premiums) because the roof is more durable to the elements.

Solar panels on the roof of a home make great (cents) sense. On the roof of a Volt, I think a consumer is throwing money away.
 

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Unfortunately, you are seriously confused about energy, power, efficiency, etc. I don't see any real calculations on your part so I'm guessing you don't have a clue. No offense.

Unfortunately, you are in lala land. Solar panels on a Volt! The average consumer is thinking at $40,000 the Volt is going to cost them about a 1/3 of what the average house in the USA cost. Add solar panels to the Volt, and not many consumers will be opting for this add-on. GM isn't interested in making add-ons for the fringe element (maybe funky/trendy after-market shops in California) but not GM in Detroit.

I have two degrees. What is your degree in? Are you an electrical engineer? No offense!

I worked for an electric company, promoted solar technology produced at our solar farm in West Texas, as well as our Zond wind turbines... Solar panels on top of a car (the size of a Volt) won't contribute any serious energy to make them marketable to consumers. You could park a Volt in El Paso all day in July and the amount of mileage gleaned from that exposure wouldn't take you to the grocery store and your dry cleaner and back. Worse, that same Volt sitting outside in November to February exposure (when the sun isn't out very long) gets you even less of a charge. You are willing to spend the $$$$$$ to have a trendy solar panel on your Volt? I'd rather buy my kilowatts at 9.5 cents from my electric company to charge my Volt. I'll be driving a lot further than you will on that investment than someone shelling out $$$$ for solar panels on top of a Volt.

Prior to working for the electric company (with the largest chunk of real-estate in Texas) I worked for the El Paso Company (largest natural gas transmission company in the USA) so please don't suggest I don't know anything about energy.

My company car at the electric company (one of 2 I vehicles I drove in my job) was a $200,000 Dodge electric van. When I was a young tyke, my father made my very first car, powered by an electric motor... I drove it for several years. I think I have more experience in owning and driving pure electric vehicles than you. And yes, I may be an old fart, but I know the economies are not yet practical for ANY car company to market a vehicle with EXPENSIVE solar panels as an option. Maybe Bill Gates could afford one, and you would be willing to bleed your bank account (or credit card) for solar panels on your Volt, but for the vast majority of consumers, we have to look at the practical ECONOMICS of how a Volt is re-charged.

Furthermore, most of the people I know living in these sun-drenched regions of the Southwest, park their cars in a garage or covered parking (except maybe when shopping)... So at this juncture, putting solar panels on the roof of a car isn't an attractive option to the consumer OR the company making the car. At 9.5 cents per kilowatt hour, you can buy a hell of a lot of electrons compared to the cost of making a car that really has some serious potential for being SERIOUSLY charged by the sun. Putting a large array of solar panels on the roof of my house seems a lot more attractive to me for charging a Volt. The fringe element (zealots) probably would be happy to pay through the nose for a solar panel on the roof of their Volt, but the economies ARE NOT THERE at this point in time or the foreseeable future FOR THE AVERAGE PERSON who would be willing to switch from a gasoline car. YOU ARE NOT AN AVERAGE PERSON. I think you are a zealot (or beyond.)

Wind turbines and solar farms making electricity for the grid is a great option as I would be interested for charging my Volt, but YOU WILL NOT SEE people driving PRODUCTION EV CARS with solar panels on the roof, hood and trunk for a decade or more :)rolleyes:give me a break!:rolleyes:)

You fail to define "do much good". It might not fit your needs but it fits my needs perfectly. I believe there will be a big enough market for the functionality that I laid out in my post above. You see no value in those functions at all? That's kind of short-sighted for someone who is working with experimental aircraft. Again, it might be of value to one person (I for one see very exciting new possibilities) and nothing to you. There have been several EVs with solar roofs so I'm guessing many designers would agree with me (Aptera, GM, Saab, etc.). There only has to be a big enough market to support such options. You don't like it? Don't check the option box.

In regard to the airplane, my flexible solar panel is to aid in keeping a battery topped-off in a small hand held radio... My engine has magnetos (do you know the principle of a magneto?) and my engine does not have an alternator or generator...







Now Sterling, Don't get yourself all worked up. We both know full well it doesn't matter who you work for. What is more important is the work you did. The things you actually designed.

OK, you wrote the following:

"I may be an old fart, but I know the economies are not yet practical for ANY car company to market a vehicle with EXPENSIVE solar panels as an option"

Well, I think it's time you took another look at solar technology. You will also get to see in less than a year that you are completely wrong. Did you see the Aptera that is about to come out? Well, here is a picture... Check out the roof:





Yup. Solar cells. No, not ten years from now. Very soon. Oh you can bet the farm that SOTS will be an option (factory installed or aftermarket). Why? Because it already is!


http://www.solarelectricalvehicles.com/



You didn't see the picture I posted? That's an aftermarket solar panel on a production car. Aptera installs their solar cells at their factory. More will be coming.

See Sterling, you fail to understand that there is more to SOTS than just driving the car. That's where you went wrong. When people see the extra functionality they can get (as I listed countless times before) they may be willing to check the option box. I for one am definitely going to. Every year the technology gets cheaper. I'm predicting all EVs will have some form of solar cells in the future. It just makes too much sense not to. Yes, they are expensive today but will be cheap in the future. You should try to relax and just accept the fact that they are coming out. Nothing you can spew is going to change that fact. They are on the road today and will be coming to the Aptera (or other EV) in the very near future (factory option or standard). Shall we place the $1 bet?
 
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