solar power

101 Articles

2026 Green Powered Challenge: Solar Powered Pi Hosts Websites In RAM

April 12, 2026 by 11 Comments

If you started with computers early enough, you’ll remember the importance of the RAMdisk concept: without a hard drive and with floppies slow and swapping constantly, everything had to live in RAM. That’s not done much these days, but [Quackieduckie]’s solar powered Pi Zero W web server has gone back to it to save its SD card.

Sustainability and low power is the name of the game. Starting with a Pi Zero W means low power is the default; a an SLS-printed aluminum case that doubles as the heat sink– while looking quite snazzy–saves power that would otherwise be used for cooling. The STLs are available through the project page if you like the look and have a hankering for passively cooled Pi. Even under load [Quackieduckie] reports temperatures of just 29.9°C,  less than a degree over idle.

The software stack is of course key to a server, and here he’s using Alpine Linux running in “diskless mode”– that’s the equivalent of what us oldsters would think of as the RAMdisk. That’s not that unusual for servers, but we don’t see it much on these pages. It’s a minimal setup to save processing, and thus electrical power, with only a handful of services kept running: lighttpd, a lightweight webserver, and duckiebox, a python-based file server, along with SSHD and dchron; together they consume 27 MB of RAM, leaving the rest of the 512 MB DDR2 the Pi comes with to quickly serve up websites without the overhead of SD card access.

As a webserver, [Quackieduckie] tested it with 50 simultaneous connections, which would be rather a lot for most small, personal web sites, and while it did slow down to an average 1.3s per response that’s perfectly usable and faster than we’d have expected from this hardware. While the actual power consumption figures aren’t given, we know from experience it’s not going to be drawing more than a watt or so. With a reasonably sized battery and solar cell– [Quackieduckie] suggests 20W–it should run until the cows come home.

This isn’t the first solar-powered web server we’ve seen, but this one was submitted for the 2026 Green Powered Challenge, which runs until April 24th.

Solar Balconies Take Europe By Storm

March 31, 2026 by 144 Comments

Solar power has been around for a long time now. Once upon a time, it was mostly the preserve of research projects and large-scale municipal installations. Eventually, as the technology grew ever cheaper, rooftop solar came along, and cashed-up homeowners rushed to throw panels on their homes to slash their power bills and even make money in some cases.

Those in apartments or rented accommodations had largely been left out of the solar revolution. That was, until the advent of balcony solar. Popular in Germany, but little known in the rest of the world, the concept has brought home power generation to a larger market than ever.

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The solar-electric tractor is out standing in its field.

Adding Solar Power To An Electric Tractor

January 2, 2026 by 9 Comments

In my country, we have a saying: the sun is a deadly lazer. Well, it’s not so much a folk saying as a meme, and not so much in one country as “the internet”. In any case, [LiamTronix] was feeling those cancer rays this harvest season when running his electric tractor, and realized that– since he’s already charging it with ground-mounted solar panels anyway–if he’s going to build a roof for his ride, he might as well make charge the batteries.

Another bonus is safety: the old Massey-Ferguson at the heart of the electric tractor build didn’t come with any rollover protection from the factory back in the 1960s. Since having however many tons of tractor roll onto you was bad enough before it got a big hefty battery pack, we heartily approve of including a roll cage in this build. Speaking of battery packs, he’s taking this chance to upgrade to a larger LiFePo pack from the LiIon pack he installed when we first featured this conversion in 2024.

Atop the new roll cage, and above the new battery, [Liam] installed four second-hand 225 W solar panels. Since that’s under 1kW even if the panels have not degraded, the tractor isn’t going to be getting much charge as it runs. In the northern winter, [Liam] is only able to pull 80 W from the set. That’s not getting much work done, but who wants a tractor without a cab or heater when it’s below freezing? In the summer it’s a much better story, and [Liam] estimates that the roof-mounted panels should provide all of the energy needed to run the tractor for the couple hours a day he expects to use it.

If you’re wondering how practical all this is, yes, it can farm  — we covered [Liam] putting the project through its paces in early 2025.

A Solar Oven For Cloudy Days

October 18, 2025 by 19 Comments

Every Boy Scout or Girl Guide probably had the experience of building a simple solar oven: an insulated box, some aluminum foil, and plastic wrap, and voila! On warm, sunny, summer days, you can bake. On cloudy days, well, you need another plan. The redoubtable [Kris De Decker] and [Marie Verdeil] provide one, with this solar-electric oven over on LowTechMagazine.

Now, you might be wondering: what’s special here? Can’t I just plug a full electric range-oven into the inverter hooked to my Powerwall? Well, yes, Moneybags, you could — if you had a large enough solar setup to offset the storage and inverter losses, that is. But if you only have a few panels, you need to make every watt count. Indeed, this build was inspired by [Kris]’ earlier attempt to power his apartment with solar panels on his balcony. His electric oven is one of the things that stymied him at that time. (Not because cooking took too much energy, but because it took too much power for his tiny battery to supply at once.)

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After Trucking Them Home, Old Solar Panels Keep On Trucking

October 16, 2025 by 69 Comments

The fact that there exist in our world flat rocks that make lightning when you point them at the sun is one of the most unappreciated bits of wizardry in this modern age. As hackers, we love all this of techno-wizardry–but some of us abhor paying full price for it. Like cars, one way to get a great discount is to buy used. [Backyard Solar Project] helped a friend analyze some 14-year-old panels to see just how they’d held up over the years, and it was actually better than we might have expected.

The big polycrystalline panels were rated at 235 W when new, and they got 6 of them for the low, low price of “get this junk off my property”. Big panels are a bit of a pain to move, but that’s still a great deal. Especially considering that after cleaning they averaged 180 W, a capacity factor of 77%. Before cleaning 14 years worth of accumulated grime cost about eight watts, on average, an argument for cleaning your panels. Under the same lighting conditions, the modern panel (rated to 200 W) was giving 82% of rated output.

That implies that after 14 years, the panels are still at about 94% of their original factory output, assuming the factory wasn’t being overoptimistic about the numbers to begin with. Still, assuming you can trust the marketing, a half a percent power drop per year isn’t too bad. It’s also believable, since the US National Renewably Energy Laboratory (yes, they have one) has done tests that put that better than the average of 0.75 %/yr. Of course the average American solar panel lives in a hotter climate than [Backyard Solar Project], which helps explain the slower degradation.

Now, we’re not your Dad or your accountant, so we’re not going to tell you if used solar panels are worth the effort. On the one hand, they still work, but on the other hand, the density is quite a bit lower. Just look at that sleek, modern 200 W panel next to the old 235 W unit. If you’re area-limited, you might want to spring for new, or at least the more energy-dense monocrystalline panels that have become standard the last 5 years or so, which aren’t likely to be given away just yet. On the gripping hand, free is free, and most of us are much more constrained by budget than by area. If nothing else, you might have a fence to stick old panels against; the vertical orientation is surprisingly effective at higher latitudes.

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Vertical Solar Panels Are Out Standing

September 25, 2025 by 98 Comments

If you’re mounting solar panels, everybody knows the drill, right? Point them south, angled according to latitude. It’s easy. In a video which demonstrates that [Everyday Dave] is truly out standing in his field, we hear a different story. [Dave] has a year’s worth of data in his Solar Panel Showdown that suggests there are good reasons to mount your panels vertically.

Specifically, [Dave] is using bifacial solar panels– panels that have cells on both sides. In his preferred orientation, one side faces South, while the other faces North. [Dave] is in the Northern Hemisphere, so those of you Down Under would have to do the opposite, pointing one face North and the other South.

Since [Dave] is far from the equator, the N/S vertical orientation beats the pants off of East-West facing panels, especially in winter. What’s interesting is how much better the bifacial panels do compared to the “standard” tilted orientation. While peak power in the summer is much better with the tilted bifacial panels (indeed, even the tilted single-sided panels), in winter the vertical N/S panels blow them out of the water. (Especially when snow gets involved. Vertical panels don’t need sweeping!)

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The Practicality Of Solar Powered Meshtastic

September 17, 2025 by 19 Comments

A Meshtastic node has been one of the toys of the moment over the last year, and since they are popular with radio amateurs there’s a chance you’ll already live within range of at least one. They can typically run from a lithium-ion or li-po battery, so it’s probable that like us you’ve toyed with the idea of running one from a solar panel. It’s something we have in common with [saveitforparts], whose experiments with a range of different solar panels form the subject of a recent video.

He has three different models: one based around a commercial solar charger, another using an off-the-shelf panel, and a final one using the panel from a solar garden light. As expected the garden light panel can’t keep an ESP32 with a radio going all day, but the other two manage even in the relatively northern climes of Alaska.

As a final stunt he puts one of the nodes out on a rocky piece of the southern Alaskan coastline, for any passing hacker to find. It’s fairly obviously in a remote place, but it seems passing cruise ships will be within its range. We just know someone will take up his challenge and find it.

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