9 Comments

People like me have a lot of time on our hands. If I only drive once a week, and it takes four days to charge my car, so be it :)

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No. Its a non-starter for practical use. The energy balances are easy to do and its easy to show that this idea has no merit.

Solar card will only exist as one-off university type projects, with slow impractical vehicles that can take one passenger in what is essentially a bicycle frame.

Its all basic math.

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Did you actually watch the idea before commenting? It does not appear so.

Aptera already has production-intent vehicles that disprove your supposed “basic math” calculations.

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This project was getting some press a couple years ago, its perf specs were slightly better than I expected, but they were also nameplate data. It may have been a paper car at that time, now maybe its real. It all comes down to energy flux - the input limit is maybe 1 kW/m2 insolation X Area X eta (say 25% to be generous) and that is what you have to work with. Then its a parametric optimization (and compromise) of size/area, weight, speed, range, storage cap, frequency of ops, and payload. If it has regen braking that might help.

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Not true. In real life. These things are not practical vehicles. Honestly, is easy to prove with basic energy balances. I assume you do energy balances your self. I have done these calcs decades ago, its rudimentary.

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OK, then show me the calculations using Aptera’s official specs showing that their production-intent vehicle cannot exist (as they claim).

And I still do not see the slightest evidence that you actually watched the video or studied the specs.

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I will look at it this weekend. I do engineering energy analysis all day, every day.

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First let me say that it CAN exist, the question is, what is it?

- I briefly looked at the specs on the website.

- The key number is 700 Watts, which is the max energy flux to the vehicle from the sun.

- 700 Watts is less that one HP, and over say a 10 hour sun day amount to less than 10 HP-hr of energy which is approx. the amount of energy in 1/2 litre of gasoline.

- The 700 Watts is in line with the initial calc I stated, which is 1000 Watts/m2 (insolation) X 20-25% efficiency X plan view area of vehicle which is maybe 3 or 4 m2. So 700 Watts is fine.

- They state on the website that coefficient of drag is worse than a solar racer but better than a Tesla.

- They state on the website 'Aptera is the first Solar Electric Vehicle that can require no charging for most daily use.' What this is saying is that this really a lightweight BEV and the solar panels are supplementary.

- Bottom line is this is a consume grade 2-seater Solar Racer type deal - basically a three-wheeled bicycle with a hard shell and solar PV panels.

- Its a fine product, but its meant for a really niche audience.

- It isnt, and cant ever be, a general purpose vehicle for mass transport - it is limited by the MAX energy input of 1/2 gasoline equivalent per day. When I say this is going nowhere, or has no chance, this is what I am referring to. As I said I have seen this before, and the basic numbers are easy to do, and its max potential is easy to determine.

Cheers. If you want more energy analysis, I am glad to help.

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That is not a very sophisticated analysis. You just verified that their claims are correct. I already knew that (or at least strongly suspected it).

Aptera is clearly a solar-powered electric vehicle (as in the title of the video), which in your first response you said was not possible.

Aptera is also a “ general purpose vehicle for mass transport.” Its main constraint is only having two seats, which I mentioned in the video. Yes, it has a niche audience for that reason, but I already said that in the video.

Your original comment was clearly incorrect. You said:

"Its a non-starter for practical use. The energy balances are easy to do and its easy to show that *this idea has no merit.*

Solar card will only exist as one-off university type projects, with slow impractical vehicles that can take one passenger in what is essentially a bicycle frame."

You have proven yourself incorrect.

Next time, please watch the video before commenting. It is a commenting rule at this site.

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