this post was submitted on 05 Dec 2023
412 points (97.2% liked)
Technology
59289 readers
4645 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related content.
- Be excellent to each another!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, to ask if your bot can be added please contact us.
- Check for duplicates before posting, duplicates may be removed
Approved Bots
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Clearly you've never ~~owned an air fryer~~ wanted a solar powered car. Or imagine shipping containers covered in these powering the trucks that haul them! Or trains! Even boats. Basically any kind of self powered transit, especially ones with greater surface area.
Second edit: Another idea! Clingfilm solar panels for windows, or blinds and curtains that can power the lights!
Or wind turbines skinned in thin, light, flexible solar panels. You'd double dip on energy per square meter. You could have a solar farm on a stick that also makes wind energy.
If you dream of covering a vehicle with panels and have it driven by that power, I have to burst your bubble. That's not even nearly enough surface to generate enough power. Perhaps assist in trickle charging battery, sure. But we already have flexible panels, even self-adhesive ones. And again, their biggest downside is not their thickness but efficiency. There will never be a self-propelled vehicle. Just a nature of things.
As for window blinds, etc. There is already glass that lets enough light through and can generate electricity. Those are even worse when it comes to efficiency due to non-ideal angle, light passing through, etc.
"We already have technology that doesn't do those things well enough, so this new technology that won't see advancement ever has no chance of addressing these issues either."
Trickle charge is awesome. Trickle charge the semi during your 8 hour driving shift and then another 8 hours while the trucker is asleep. If that nets half a charge every other day, that's a charge and a half a week. It's not self powered like a perpetual motion device, those aren't real. But regenerative braking is a worthwhile addition to an electric truck. Why wouldn't solar paper or whatever we want to call it also be part of the solution?
More like, it would take 8 days of constant sun to have an hour of driving.
Currently. Technology gets better
No, there is literally only so much energy radiated by the sun in a certain area. The number of square feet of roof on a car is just too small to propel it, even with magic theoretical 100% efficient panels.
You do know cars don't have to move all the time right? If I was on a road trip and got stuck because of no juice for whatever reason, I would be able to camp wherever I am for a couple days and then have enough to move.
Your thinking is pretty small minded
This isn’t some theoretical thing I’m making up. It’s really basic math and physics you should have learned in high school. To do a trip of a few miles you would have to charge for a week. Here is a good explainer with demonstration cars that have been physically built, maybe that will help drive the point home.
As outlined elsewhere in this thread, you'd have to move the Earth closer to the sun for this to be feasible. You can only get so much solar power as it stands, and even 100% efficient panels would only go so far.
Nah. Even 1% power is better than 0% power
Not when it costs any amount of money to do so.
There are physical limits at play to how much power this can provide. No amount of technological improvement can break them.
Imagine the driver plugging in the truck during the 8 hours while they're asleep. That's an achievable goal.
Here's a video of a camper van with traditional solar panels on the roof using a slide-out awning technique.
https://youtu.be/Ev5C9gf0zFc?si=97piy-3mV9TIsRlu
You might say that's impractical for regular use. Sure, it is, but your previous argument was that is was impossible due to physics, which the video clearly shows isn't physically impossible, so we're already much closer to a reality. I'm not saying it could drive forever without stopping or be the only power source. That's silly. But if it reduces the need to charge from a grid by X% it can be a useful technology. Go on now and tell me how it could never ever work.
A camper van. Which has electrical use for things besides turning a motor. Yeah, that's useful, but it doesn't exactly help your case.
Under optimal conditions, the sun gives us 1000Wh per square meter. Let's say you have a 100% efficient solar panel. A semi truck trailer has a max of 42 sq meters on top of its trailer. So you get 42kWh out of this.
It takes about 280kWh to keep a semi truck at cruising speed on the highway. Thus, in this most optimal scenario, it would give you an additional 15%. Even this assumes there is no additional aerodynamic drag from the panels, mounting hardware, or wiring. It wouldn't take much to completely blow that 15% away.
If it's a cloudy day, all of it is now deadweight, and now hurts more than it helps. If you don't drive on the equator, its output drops and it now hurts more than it helps. If you have solar panels that actually exist that do around 20% efficiency instead of 100%, it now hurts more than it helps.
I guess we could move the Earth closer to the sun. Won't help our global warming problems, though.
It also turns the motor bro, did you watch it?
Of course it does. Doesn't mean it's a good idea.
Did you math?
You first said is was physically impossible. I've shown you it wasn't and predicted you'd move the goal post from possibility to practicality. And you did. Thanks for proving that you don't really care about whether it could even possibly work, but just that you wanna dunk on excitement and be right on the Internet. Have a good day.
I never said this.
"There are physical limits at play to how much power this can provide. No amount of technological improvement can break them."
Also, the fact it powers the motor for the camper AND all the appliances and such just proves the viability that much more, as the extra power draw is still supported by the camper's solar power system.
Yes, there are physical limits. It cannot provide enough power to justify having it only for the purposes of turning a motor. A camper van can justify it because it has lots of uses for electricity besides turning a motor, and as long as you're paying the cost anyway, might as well connect it to the battery charging circuit.
You started this conversation with:
All things that primarily turn a motor. None of these are feasible to be powered this way.
Your physics isn't terrible but you're making absurd leaps into nonsence with the rest, you also don't seem to have practical awareness of trucking logistics.
Here's a thought experiment, if sticking news paper to the outside of your truck was proven to give a 5% fuel cost reduction how long do you think it would take before you see a truck covered in news paper? Probably hours at most, truck drivers don't like stopping to piss because the extra fuel required to accelerate to highway speeds cuts into their margins so you can be damn sure that if there was an inexpensive way to reduce the cost of charging their truck everyone will be on that.
Also trunks have a lot of stuff beyond the motor, security and logging systems for example as well as various forms of climate control. Also being able to leave a vehicle idle and have it's fuel slowly increase instead of decrease / denature is a huge thing in a lot of situations.
If course is not going to make a truck that can drive a heavy load without recharging but if its only going to cost the same as a paint coating and can supply a slow trickle then it'll be a very popular product.
Even more so for things like agricultural machinery, leasure vehicles such as campers and boats, or anything with large gaps between uses.
So let's think about how a hypothetical electric truck would charge throughout the day. Driver makes a 20 minute stop and there's a 350kW charger available (about the max of what's out there for this sort of thing right now). They'll get 105kWh of charge out of that.
The top solar panels I can find at the moment are 540W and take up 2 sq meters each. So a 42 sq meter can have 21 panels for 11kW. That's the power they'd be rated for in direct sunlight on a bright day.
Even if we assume they have that direct sunlight for 12 hours straight (they won't, not even in equatorial regions), they'll get 136kWh out of that per day. Only a bit more than what they'd get out of a 20 minute stop.
US regulations require that a driver take a 30 minute break after 8 hours of consecutive driving. I also understand that this rule is broken all the time, but I don't feel the need to pander to exploitative and dangerous behaviors on the part of trucking companies.
Then we get to the cost. Those panels will be around $5000 for the set, and there are significant labor costs involved, too. Call it $10k/trailer to save a 20-30 minute stop each day that the driver will probably take, anyway.
There's also significant weight added, which reduces how much cargo they can carry. The factor you're talking about in getting the truck back up to highway speed just got worse. The panels ones noted in OP would be extremely lightweight, yes, but they also cut the power delivered in half.
None of this can happen until the industry electrifies. Current electric semi trucks are barely suitable, and there needs to be some improvements in battery tech before they can be.
This idea doesn't even look good on paper with unrealistic assumptions made in its favor. Put the solar panels at the charging stations, not the trucks.
Or better, forget about long haul trucking and replace it with electrified rail. Mount the solar panels on racks above the trains, not on the trains.
And this technology is ideal for going over rail, road, parking areas and all that sort of stuff so of course it's likely to end up used in those places.
It's also almost certainly going to be painted onto truck roofs, RVs, trailers, boat decks, fencing, marquees, and just about everything else. We'll certainly see rolls of it carried in pretty much all groups that go camping or work in off grid locations - take the roll, steak out two corners then unroll it onto a sunny bit of ground and suddenly you've got twenty square meters of PV charging your vehicles, phones, laptops, and tools. Life boats with power to run desalination equipment and satellite communications will save many lives.
At a low enough price point it's worth it just to maintain charge in an ICE's starter battery when left idle and to power monitoring systems, for electric trucks it's a no brainer - free fuel and extended range for the cost of a paint job? It doesn't matter how little range it adds or how slow the fuel trickes in it'll become ubiquitous pretty much over night.
So you did say that. But you just told me you didn't. You're confusing. I also showed you a motor powered this way yet you say it isn't feasible. So I really feel like I'm done with this conversation. Good day.
Not my fault if you don't understand the difference between "impossible" and "infeasible".
Also known as a "flag"
Ha! That could be it too, but I had meant more like a wrap around the pole.
Those all sound like efficiency issues still. Covering any form of transportation with solar panels is primarily pointless because of how little power that would generate. Even if you covered every available inch with the most efficient panels invented, it would take over two weeks of sitting in full, direct sunlight to charge a solar-powered car, which you would drain in four hours of driving. As these panels are half as efficient as traditional panels, you could drive maybe ~~a~~ two minutes per hour you sit in full sun.
Where are you getting that two weeks number?
A car has up to 55 sq. ft. available to panel. A good solar panel gets maybe 20 W/sq. ft. efficiency. An electric car has around an 80 kWh battery. A day has roughly the equivalent of 5 hours of full sunlight.
Then you just multiply/divide everything together, and you get 14½ days.
If it takes 14 days to charge the battery, you just need to use it less then a 14th of its range per day and this all becomes very feasible, no? First link on google tells me high efficiency EVs output 6.4km per kwh. That's 30 km a day at 80kwh, nothing to scoff at in my opinion, although its probably less.
I also think it could become popular to lengthen the in between charging times with higher capacity batteries.
+1 for the use of wolfram
Then factor in the extra cost of the panels and connecting hardware. The ones mentioned in OP are supposed to be dirt cheap, but they're also half as efficient. The tradeoff cancels out the benefit.
Also, this won't help highway driving much. EVs have already solved city driving just fine. 100mi range will do, even without good charging stations outside your home (with caveats for apartment dwellers). Highway range is where we need improvement, but you can't ask people to just drive for 1/14th of the day there.
Fair enough. That definitely is true for a car. I would wonder whether the power/surface area/weight/energy consumption all scale linearly or if a vehicle like a semi with more surface area could take advantage of increased number solar panels, or would the amount of work needed to move the larger truck scale equally to the power gained?
Thank you for your proving reasoning for your opinions and sources. You're groovy. Don't feel like you have to again for this random thought of mine unless it's enjoyable for you as part of our conversation.
Wait, what the fuck, dude. I had given you the math for semi trucks two hours before you posted this. You already had those numbers, and yet you speculate otherwise here.
That guy isn't being a dick. You've got a bad attitude and I don't like talking to you. Goodbye.
So... You denied reality because you didn't like the person explaining it to you? Grats, you're politician material now
No, I wasn't enjoying one conversation in the room so I went to talk to somebody else. I'm not required to talk to them and I am free to explore a topic with someone else without citing previous discussions I've had. I deny nothing that guy said, though I also don't take it as face value when they also ignored my points in the thread, I'd just rather talk to this person about it if they'd care to.
I'm often a dick to people arguing dishonestly. Guilty.
Oh just fuck off. You're seriously chasing me around the comment section, butthurt because I'd rather talk to somebody less unpleasant. You're not changing my perspective if that's why you're doing it.
Gotta be useful during the zombie apocalypse though. No more raiding gas stations and broken down vehicles.