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Electric car that charges itself

sonomotors.com

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Re: Electric car that charges itself

#301

Post by 40four »

iso1631 wrote: post #281
40four wrote: post #220

Earlier quoted context omitted.

This topic came up on the recent Joe Rogan with Elon Musk. Elon said they considered it, but in the end it is just not worth it. He said there is just not enough surface area on a car to contribute a worthwhile amount of electricity. The numbers quoted for this particular vehicle are very optimistic I think. If you’re lucky, you might get 5 miles a day out of it. What happens if it’s cloudy or rainy for a week? Or yo…

Musk is building cars for a mainly american style market - long drives and private parking. topping up 5 miles a day means that a full battery will last me and the 1.8 million UK cars that do under 2000 miles a year, months between having to plug in and recharge.

That's a good point. There are cars for the European market, and I don't think we'll be seeing many in the states.

My main point though, is that the amount of electricity you can collect from the surface area of a car is very negligible. It's a very ambitious goal indeed. It's not worthless, it's basically free energy so anything gained is good I guess. It just seems there are a lot of people here that seem to think this is going to be better than it actually is. It's easy to get hyped up by the marketing, but my suspicion is it is much worse that we would wish.

I'm very skeptical of the numbers they have posted. Especially in England where hours of sunlight per year is below average. A quick search suggests England on average get roughly 1500 hours of sunshine per year. Comparatively, my state of South Carolina get upwards of 2800 hours. You should be looking at the 'cloudy' bars on the chart (https://sonomotors.com/en/solar-integration/). Assuming the charts are right, that's 77 Km per week at peak summer, and as low as 21 KM per week in the winter, realistically. If the weather of favorable, and you don't park in shade, then sure you could get better results.

We have basically reached the limit of what we can extract from solar cells, and there is not enough surface area on a small car to make 'the dream' come true, of having the car charge itself without plugging in.

It looks great on the marketing campaigns though. And I'll give this company credit, their body panel system does look very innovative. It seems they have made some important enhancements in this type of solar tech. And all things considered, the more electric cars on the road the better, I hope they sell a ton of them!

Re: Electric car that charges itself

#304

Post by hourislate »

mbreese wrote: post #233
agumonkey wrote: post #226

Earlier quoted context omitted.

He didn't mention the semi ? The large flat area, long time under the sun, difference of market (no need to integrate it pretty, a simple flatbed on top would do)

Semi trucks and trailers are two different components. Most trailers have a large flat area, but these can get swapped often. And even within the same company you won’t always have the solar trailer hooked up to the electric semi. The swappable nature of the load is part of the appeal of semis. I guess what I’m saying is, even if you had a solar trailer, you would lose a lot of the load flexibility of using a semi tr…

Trailer manufacturers could make all trailers solar (panels on the roof of the trailer) and have a battery pack somewhere in the area a refer unit would sit. This way you could power the refer if there was one or the the Truck if there was no refer unit and the Truck was electric. They become a energy storage unit while not in use (sitting in lots). I think this is what we'll see when there will be more Electric Semi's on the road.

Re: Electric car that charges itself

#305

Post by labcomputer »

coldcode wrote: post #215
dreamcompiler wrote: post #7

This idea will never be practical but it also seems it won't die. 69 miles per week of charging. Assuming the car is sitting outdoors all week and the weather is not cloudy. A Tesla can charge more than this in an hour.

For a site devoted to people who love technology this is short sighted thinking. People thought the iPhone was a gimmick too that would never sell. You are looking at a development model of an idea: what happen 10 years down the road when solar technology improves like everything else and becomes light and more efficient. People thought Tesla would never work as well when it started. People thought Ford would never s…

> For a site devoted to people who love technology this is short sighted thinking

It's not short sighted thinking: Most people who use this site can do basic arithmetic.

The solar radiance under AM1.5 (which approximates the surface of the earth at the latitude of Europe, the US, or China) is around 1000 kW/m^2. The very best multi-bandgap solar cells in the lab today are about 47% efficient at converting sunlight to electricity. The very best DC-DC converters have about 95% efficiency in practice.

That means upper bound on energy production is about 445 W/m^2. On a sunny day. At noon. In June. For a panel directly facing the sun. With no shade.

That means you need slightly more than 3 m^2 of sun-facing panels at noon to achieve just the charging rate of a basic 120V North American household plug (1.44 kW from a NEMA 5-15, to be precise).

That means you need well over 3 m^2 of body-conforming panel to achieve that rate at noon. And that's the best case given infinite money. And production at other times of the day will be lower (even if you assume the car is parked in the middle of a flat desert).

Since the sun moves throughout the day, leaving such a car in the sun all day will only charge it about as much as charging from household plug for about 3-5 hours. Showing that is left as an exercise to the reader.

Re: Electric car that charges itself

#306

Post by burlesona »

That looks awesome! Living with a family in a sunny urban area, and not driving a whole lot (typically 0-4mi per day), I think we could get pretty far with that kind of charge capacity and range. I also love that it seems to be a van but looks a little more rugged and utilitarian compared to the typical soft and cushy look of minivans here in the US.

Too bad it seems to be EU only.

Re: Electric car that charges itself

#307

Post by hnuser123456 »

40four wrote: post #301
iso1631 wrote: post #281

Earlier quoted context omitted.

Musk is building cars for a mainly american style market - long drives and private parking. topping up 5 miles a day means that a full battery will last me and the 1.8 million UK cars that do under 2000 miles a year, months between having to plug in and recharge.

That's a good point. There are cars for the European market, and I don't think we'll be seeing many in the states. My main point though, is that the amount of electricity you can collect from the surface area of a car is very negligible. It's a very ambitious goal indeed. It's not worthless, it's basically free energy so anything gained is good I guess. It just seems there are a lot of people here that seem to think…

I really can't understand your POV. Of course it doesn't mean never having to visit a charger for cross-country trips, which is obviously a dream. It does mean the car adds charge passively rather than losing it, the panels are silly cheap compared to the cost of batteries, and the hardest part would just be integrating them into the body panels, which is certainly achievable. See my other comment in this thread where I can easily think of 5-6 significant benefits. There's really no reason not to do it, if we don't mislead people into thinking it means infinite range in the sun. The only other criticism I can think of is that people won't like how it looks, but that's their loss.

And in fact, for my short commute and I'm sure at least a few others, it would mean never having to visit a charger except for long trips.

Re: Electric car that charges itself

#308

Post by everdrive »

orthecreedence wrote: post #298
dheera wrote: post #277

Earlier quoted context omitted.

Honestly I don't see why we can't just outlaw HOAs. If you own something you should be able to do whatever you want with it. It seems like a simple constitutional right to me.

I personally hate the idea of HOAs, so I agree with you on a gut level. Taking a wider view, HOAs are a form of free association and I can't condemn them entirely. If people want to subject themselves to complete hell, they should be able to. And frankly, the kind of neighborhood that has an HOA is not the place I'd want to live anyway, so it's not like I'm personally missing anything. That said, the existence of HOA…

>HOAs are a form of free association and I can't condemn them entirely.

I think an argument against this is that the HOA follows the property, not the consumer. If I could opt out of an HOA when purchasing a home, it wouldn't be so bad. (but then again, the HOA would likely be severely weakened.)

Re: Electric car that charges itself

#309

Post by eldaisfish »

ben_w wrote: post #296
eldaisfish wrote: post #239

Earlier quoted context omitted.

that's precisely my point. Even if most of the $2/W cost of commercial PV isn't the cell cost, the cells still cost around US$ 0.4 - 0.6 each and this is for mass produced cells. Is it fair to claim that a speciality cell such as those on this car can be had for even cheaper? Unlikely.

I’m not sure what you’re arguing against given I claimed $.30/W and the document you linked me to also claims $.30/W cells.

For posterity, NREL's number is $ 0.47 / W for utility scale solar. It's not $ 0.30 /W and there's no way a speciality cell is cheaper than utility scale cells.

Re: Electric car that charges itself

#310

Post by scbrg »

SideburnsOfDoom wrote: post #162
scbrg wrote: post #154

Earlier quoted context omitted.

Running out over the pavement to the cars in the street? With infrastructure to handle the problem of residents not necessarily being able to park in front of the buildings they live in. It seems non trivial to me.

> Running out over the pavement to the cars in the street? You seem sceptical? I've seen exactly that in a street near me, to a motor vehicle being charged up. They used a cable protector, this kind of device: https://www.kingfisherdirect.co.uk/traffic-line-hose-and-cab... However, more permanent infrastructure would be buried below the paving. This already happens, BTW. Cities need infrastructure, that's just the fa…

I am sceptical. At least around here I strongly doubt that it'd even be legal to run that thing (or several of those things) across the pavement. Pavements are for walking, prams, wheelchairs and whatnot that would be obstructed. I might be wrong there though.

I'm not arguing against the idea that such infrastructure would be good. I'm just saying that a private person renting an apartment in a city can not reasonably be expected to slap solar panels on the roof of the building they don't own, illegally run cables over the pavement they don't own to their cars that may or may not be possible to park near the building they live in.

To them, a car that "charges itself", even significantly less efficiently, may indeed be a better solution.

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