this post was submitted on 20 Jul 2025
131 points (94.0% liked)
No Stupid Questions
42389 readers
1641 users here now
No such thing. Ask away!
!nostupidquestions is a community dedicated to being helpful and answering each others' questions on various topics.
The rules for posting and commenting, besides the rules defined here for lemmy.world, are as follows:
Rules (interactive)
Rule 1- All posts must be legitimate questions. All post titles must include a question.
All posts must be legitimate questions, and all post titles must include a question. Questions that are joke or trolling questions, memes, song lyrics as title, etc. are not allowed here. See Rule 6 for all exceptions.
Rule 2- Your question subject cannot be illegal or NSFW material.
Your question subject cannot be illegal or NSFW material. You will be warned first, banned second.
Rule 3- Do not seek mental, medical and professional help here.
Do not seek mental, medical and professional help here. Breaking this rule will not get you or your post removed, but it will put you at risk, and possibly in danger.
Rule 4- No self promotion or upvote-farming of any kind.
That's it.
Rule 5- No baiting or sealioning or promoting an agenda.
Questions which, instead of being of an innocuous nature, are specifically intended (based on reports and in the opinion of our crack moderation team) to bait users into ideological wars on charged political topics will be removed and the authors warned - or banned - depending on severity.
Rule 6- Regarding META posts and joke questions.
Provided it is about the community itself, you may post non-question posts using the [META] tag on your post title.
On fridays, you are allowed to post meme and troll questions, on the condition that it's in text format only, and conforms with our other rules. These posts MUST include the [NSQ Friday] tag in their title.
If you post a serious question on friday and are looking only for legitimate answers, then please include the [Serious] tag on your post. Irrelevant replies will then be removed by moderators.
Rule 7- You can't intentionally annoy, mock, or harass other members.
If you intentionally annoy, mock, harass, or discriminate against any individual member, you will be removed.
Likewise, if you are a member, sympathiser or a resemblant of a movement that is known to largely hate, mock, discriminate against, and/or want to take lives of a group of people, and you were provably vocal about your hate, then you will be banned on sight.
Rule 8- All comments should try to stay relevant to their parent content.
Rule 9- Reposts from other platforms are not allowed.
Let everyone have their own content.
Rule 10- Majority of bots aren't allowed to participate here. This includes using AI responses and summaries.
Credits
Our breathtaking icon was bestowed upon us by @Cevilia!
The greatest banner of all time: by @TheOneWithTheHair!
founded 2 years ago
MODERATORS
People always severely underestimate how little power solar panels actually produce. In optimal conditions they get around 1000 watt per square meter, but are only around 20% efficient. So that means 200 watt produced at the panel. Once you convert that into something useable and transport it to where you need it, you'll probably lose another 5 - 10%. And that's a square meter, that's more than you can comfortably carry. Think a flat panel of around 2 meters in length and 0.5 meters wide and lifting that above your head, pointed perfectly at the sun.
And the reality is, most solar panels even in permanent installations don't experience perfect conditions. They don't track the sun, so most of the time they aren't perfectly aligned to catch all that energy. They are most likely never aligned perfectly, or if they are just a few days out of the year for like an hour a day. The sun isn't always out, not just because you know night time, but also because of clouds and other weather or human related stuff. Lots of times there are shadows that prevent optimal workings. Dust and grime also plays a part. But another thing is temperature, solar panels are rated at around 20 degrees C. But when you put a black thing in full sun, you know it's going to get scorching hot. This also reduces the amount of energy you can usefully extract from the sunlight as well.
The annoying thing about solar panels is they aren't linear at all. It isn't like when conditions are 80% from optimal, they produce 80% of the power. No, usually it's more like 60%. And once you drop below 40% of optimal, you just produce basically zero. With a bit of effort this can be improved upon. For example I use microinverters which can regulate each panel individually, but even then it's not great. And that's with state of the art panels, which are very fragile, so they have a sturdy metal frame, a very tough plastic backing and a big ass layer of glass on top to protect them. If you get those more sturdy thin and light panels, you'll be lucky if they get 15% efficiency (most likely a lot less).
So putting solar on anything that isn't a permanent installation is usually pointless. It's way too hard to get those ideal conditions and the panels aren't very good to start with. If it's moving, it's hard to point at the sun all the time. Exceptions are maybe a small panel on the top of a campervans, which is probably the best case for a mobile installation and gets just a little bit of energy. But only if it doesn't disrupt the wind profile of the van, otherwise it probably costs more in gas to push it along at high speed than it ever delivers back in electricity. One of those small foldable panels can also be useful when hiking for example. You can carry it collapsed on your back and if you take a break, you can fold it out, point it at the sun and get some useful energy for a couple of hours while you get some rest. Putting it on when hiking would be pointless, as it would be bulky when folded out, usually not pointed at the sun and under cover of trees for example.
Maybe the technology will improve in the future, but for now any useful personal solar is very niche.
Right, but it also depends on the application. It would definitely be enough for charging your phone a whole day at a festival. I've been using one of those "hiking" panels that you can put on a backpack. It is rated at 15 W, but I get less than 5 W out of it, which is still enough for charging my phone and not having to use a powerbank for the whole duration of the festival week; if it is sunny that is. I would love not having to bring both, an umbrella and the solar panel. E.g. Hellfest this year really was hot as hell, it definitely would have worked for this application.
But folding and weight would be a problem, and I don't see it useful for any other scenarios. (E.g. at the beach or other one-day-events you just charge your phone at home/hotel and can use it the whole day.)
You're not gonna be lining a flexible handheld device with the kind of solar panels that can achieve such efficiencies even under ideal conditions. If you want an actual parasol rather than an unwieldy, rigid, parasol shaped bed for a bunch of solar panels, this is a job for the more alternative solar cell types that are cheaper and less efficient, but can be made thinner and lighter, and can be stuck on something like that. Unfortunately those generally have piss poor efficiency and they degrade to near uselessness very quickly.
It's a better product idea than you make out.
It does require industrial design, and tooling for flexible panel manufacturers to make umbrella patterned panels, as cheaply as rectangular patterned ones.
Flexible panells top out closer to 25% efficiency than 20%. 200-250w is a lot of power. The umbrella itself needs just a hook for a battery rather than coming with one. Solar or USB (up to 240w at 48v power) interfaces. This can power a mini pc with a couple of large monitors with power left over. 1kwh per day/m^2^ is enogh to cover a high power laptop, electric cooking, or if it were a beach parasol, keep a drink fridge cool, and boom box TF out of the place. Because you need an ebike to lug all of the crap to the beach, it can charge it back up. Besides beach use, a parasol would allow supplementary power for van/RV or even a house, when not beach party boomboxing.