Students’ solar-powered camper van turns heads on 1,800-mile road trip | Hacker News Reader

Students’ solar-powered camper van turns heads on 1,800-mile road trip

theguardian.com

77 pointssamizdis20 comments

A better article with more technical information, but in Dutch:

https://tweakers.net/nieuws/186696/tu-eindhoven-toont-zonnec...

Seems it can drive 180 km on a sunny day using the panels alone. The batteries can hold an (additional) charge of 600 km.

This is awesome, but I got some bad news for this guy:

"If 22 students can design and build a vehicle like this in one year, then I’m sure companies could as well."

22 motivated smart people, guided by profs, with likely a lot of goodwill from manufacturers, are putting in free labor/overtime into a project with no need for profit or even a business-case.

That's not what companies do. But its good to see universities do it.

I wonder how they got to 450 miles a day on solar. I remember the Prius solar roof option would only give you a couple of miles a day in ideal circumstances. This camper has more panels but that’s still a bit jump to 450 miles.

That 450 miles will also use up the electricity stored in the 60kWh battery. So you'd get one day to travel 450 miles and then either have to plug in to charge, or use the solar panels to regain range. They mention being able to gain a full charge in 2-3 days if stationary, which is impressive. Given the 60kWh battery they must be getting around 20kWh/day from the panels.

It sounds like they are averaging around 60 miles/day on their road trip. Given the regular RV loads they will have for cooking and lighting, in addition to cloud days, it seems like they are fully utilizing their solar gain.

I remember a lecture at university where we assumed a cars body was 100% covered in solar panels and that the sun was hitting all panels simultaneously and that the panels were 100% efficient and the car was above the earths atmosphere and we calculated that the power produced was equivalent to 6HP or the size of a riding lawn mower engine. It was meant to show that physics forbade a solar powered car as we knew them.

Is it a limit on acceleration coupled with larger solar area that allows this?

I calculated a similar maximum horsepower to your own estimation (6.1 hp) when I used the average direct solar radiation (164 W m^2 @ 27 m^2 surface). This rose to 41 hp when using values for "a typical cloudless day at solar zenith" (1120 W m^2) [1]. The wattage will square when doubling each side, so if you were to double each length of the surface, you'd be up to 151 extremely hypothetical hp - just like the Honda Insight!

Back on planet earth, the most common solar panels have efficiencies between 15-20% [2]. Direct radiation is diminished by the cosine of the angle of solar tilt. It takes another ~2 hp to overcome drag at just 30mph [3]. Who knows how much this setup would weigh. You'd have to be Speed Racer's long-lost brother in Arizona to win a mid-summer dead-heat race at noon with a go-cart.

[1] https://www.newport.com/t/introduction-to-solar-radiation

[2] https://css.umich.edu/factsheets/photovoltaic-energy-factshe...

[3] https://web.archive.org/web/20190616063447/http://phors.loco...

Way more panels, as seen in this image [1] and shown on specs [2] as 17.5 m^2 of panels unfolded.

[1] https://images.prismic.io/solarehv/62d397ae-9839-4d31-b316-a...

[2] https://vita.solarteameindhoven.nl/about-show

OK but 5x the panels makes for 10-20 miles a day not 450. Also with the panels extended you would not be able to drive, so you would alternate driving and charging days.

Technology has advanced since the Prius solar roof, which was never a serious option to begin with.

By going downhill.

It’s the Netherlands.

I love projects like these because they show the sheer power of the light that hits the Earth.

Of course I don't count on such vehicles ever becoming popular, but it's great to know that nowadays you can put panels on your rooftop, which are not only cheaper per Watt, but also provide 50% more power per unit area than what was available just a decade ago.

The article says the trip is "an 1,800-mile (3,000km) road trip across western Europe".

Are you allowed to drive around in self built vehicles in Europe? Or did they convince all countries they cross to give them a special permit?

How does that even work? When the polic stops them and says "The papers of the car please", they say "Hey, check this out, we have a letter from your chancellor who says we are cool to do this". Then how would the police even know how to check if that is legit?

> Are you allowed to drive around in self built vehicles in Europe? Or did they convince all countries they cross to give them a special permit?

The car has been inspected by the RDW (Dutch vehicle authority) [1] and given a vehicle registration plate. So yes, they're allowed to drive around :)

[1] https://www.tue.nl/en/our-university/departments/biomedical-...

A common technique is the "car of Theseus": the rules for modified cars are often more relaxed, but you can quite drastically modify a car before you have to recertify it. It may be (and I can't find evidence either way) that they have a donor car with its original VIN as the chassis and have rebuilt that from the ground up.

In the UK at least, as long as you meet the requirements for road safety (which are remarkably little, for custom cars), you can register custom vehicles on the road. We have a wonderful history of insane people building cars in their sheds: https://www.youtube.com/watch?v=0DGtf7asP8I

Yes, you get it approved at the 'RDW'. Checking the plates (N-784-BX) at https://ovi.rdw.nl/ gives you a bit more info. Like, the list price of €4.235.000 :-)

The website says it's road legal and has a license plate: https://vita.solarteameindhoven.nl/

Here's a blog post from when they registered a previous car a few years ago: https://web.archive.org/web/20210506002307/https://solarteam...

I think they have a genuine registration from the Netherlands that they can produce if someone stops them.

I think the rule is this: if your vehicle is considered roadworthy in one country as evidenced by passing a roadworthiness test, called an MOT test in the UK, Contrôle Technique in France, ITV in Spain (those are the ones I know) it will qualify for insurance. If it has passed a qualifying roadworthiness test, and is insured in one country, that is legally valid throughout Europe. There is in fact a larger agreement regarding insurance and roadworthiness that some nearby countries such as Morocco and Turkey also participate in, I'm afraid I don't recall its name right now.

Love to see stuff like this.

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