Solar Hacks

210 Articles

A photo montage of scrap plastic being vacuumed up, processed in the main chamber, and bottled in gas tanks.

Solar Powered Pyrolysis Facility Converts Scrap Plastic Into Fuel

August 23, 2025 by 30 Comments

[naturejab] shows off his solar powered pyrolysis machine which can convert scrap plastic into fuel. According to the video, this is the world’s most complex hand-made pyrolysis reactor ever made. We will give him some wiggle room there around “complex” and “hand-made”, because whatever else you have to say about it this machine is incredibly cool!

As you may know pyrolysis is a process wherein heat is applied to organic material in an inert environment (such as a vacuum) which causes the separation of its covalent bonds thereby causing it to decompose. In this case we decompose scrap plastic into what it was made from: natural gas and petroleum.

His facility is one hundred percent solar powered. The battery is a 100 kWh Komodo commercial power tank. He has in the order of twenty solar power panels laying in the grass behind the facility giving him eight or nine kilowatts. The first step in using the machine, after turning it on, is to load scrap plastic into it; this is done by means of a vacuum pump attached to a large flexible tube. The plastic gets pumped through the top chamber into the bottom chamber, which contains blades that help move the plastic through it. The two chambers are isolated by a valve — operating it allows either chamber to be pumped down to vacuum independently.

Once the plastic is in the main vacuum chamber, the eight active magnetrons — the same type of device you’d find in your typical microwave oven — begin to break down the plastic. As there’s no air in the vacuum chamber, the plastic won’t catch fire when it gets hot. Instead it melts, returning to petroleum and natural gas vapor which it was made from. Eventually the resultant vapor flows through a dephlegmator cooling into crude oil and natural gas which are stored separately for later use and further processing.

If you’re interested in pyrolysis you might like to read Methane Pyrolysis: Producing Green Hydrogen Without Carbon Emissions.

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A photo of the circuit board with components soldered on

A Solar-Only, Battery-Free Device That Harvests Energy From A BPW34 Photodiode

August 10, 2025 by 21 Comments

Normally when you think solar projects, you think of big photovoltaic cells. But a photodiode is just an inefficient, and usually much smaller, PV cell. Since [Pocket Concepts]’s Solar_nRF has such a low power budget, it can get away with using BPW34 photodiodes in place of batteries. (Video, embedded below.)

The BPW34 silicon PIN photodiode feeds a small voltage into a BQ25504 ultra-low-power boost converter energy harvester which stores power in a capacitor. When the capacitor is fully charged the battery-good pin is toggled which drives a MOSFET that powers everything downstream.

When it’s powered on, the Nordic nRF initializes, reads the current temperature from an attached I2C thermometer, and then sends out a Bluetooth Low Energy (BLE) advertising packet containing the temperature data. When the capacitor runs out of energy, the battery-good pin is turned off and downstream electronics become unpowered and the cycle begins again.

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Solar Light? Mains Light? Yes!

July 29, 2025 by 21 Comments

So you want a light that runs off solar power. But you don’t want it to go dark if your batteries discharge. The answer? A solar-mains hybrid lamp. You could use solar-charged batteries until they fall below a certain point and then switch to mains, but that’s not nearly cool enough. [Vijay Deshpande] shows how to make a lamp that draws only the power it needs from the mains.

The circuit uses DC operation and does not feed power back into the electric grid. It still works if the mains is down, assuming the solar power supply is still able to power the lamp. In addition, according to [Vijay], it will last up to 15 years with little maintenance.

The circuit was developed in response to an earlier project that utilized solar power to directly drive the light, when possible. If the light was off, the solar power went to waste. Also, if the mains power failed at night, no light.

The answer, of course, is to add a battery to the system and appropriate switching to drive the lights or charge the battery and only draw power from the mains when needed. Since the battery can take up the slack, it becomes easier to load balance. In periods of low sunlight, the battery provides the missing power until it can’t and then the mains supply takes over.

Comparators determine whether there is an under-voltage or over-voltage and use this information to decide whether the battery charges or if the main supply takes over. Some beefy MOSFETs take care of the switching duties. Overall, a good way to save and reuse solar cell output while still drawing from the grid when necessary.

Small solar lights don’t take much, but won’t draw from commercial power. Solar “generators” are all the rage right now, and you could probably adapt this idea for that use, too.

COTS Components Combine To DIY Solar Power Station

June 12, 2025 by 19 Comments

They’re marketed as “Solar Generators” or “Solar Power Stations” but what they are is a nice box with a battery, charge controller, and inverter inside. [DoItYourselfDad] on Youtube decided that since all of those parts are available separately, he could put one together himself.

The project is a nice simple job for a weekend afternoon. (He claims 2 hours.) Because it’s all COTS components, it just a matter of wiring everything together, and sticking into a box.  [DoItYourselfDad] walks his viewers through this process very clearly, including installing a shunt to monitor the battery. (This is the kind of video you could send to your brother-in-law in good conscience.)

Strictly speaking, he didn’t need the shunt, since his fancy LiFePo pack from TimeUSB has one built in with Bluetooth connectivity. Having a dedicated screen is nice, though, as is the ability to charge from wall power or solar, via the two different charge controllers [DoItYourselfDad] includes. If it were our power station, we’d be sure to put in a DC-DC converter for USB-PD functionality, but his use case must be different as he has a 120 V inverter as the only output. That’s the nice thing about doing it yourself, though: you can include all the features you want, and none that you don’t.

We’re not totally sure about his claim that the clear cargo box was chosen because he was inspired by late-90s Macintosh computers, but it’s a perfectly usable case, and the build quality is probably as good as the cheapest options on TEMU.

This project is simple, but it does the job. Have you made a more sophisticated battery box, or other more-impressive project? Don’t cast shade on [DoItYourselfDad]: cast light on your work by letting us know about it!. Continue reading “COTS Components Combine To DIY Solar Power Station” →

SkyRoof, A New Satellite Tracker For Hams

June 10, 2025 by 13 Comments

Communicating with space-based ham radio satellites might sound like it’s something that takes a lot of money, but in reality it’s one of the more accessible aspects of the hobby. Generally all that’s needed is a five-watt handheld transceiver and a directional antenna. Like most things in the ham radio world, though, it takes a certain amount of skill which can’t be easily purchased. Most hams using satellites like these will rely on some software to help track them, which is where this new program from [Alex Shovkoplyas] comes in.

The open source application is called SkyRoof and provides a number of layers of information about satellites aggregated into a single information feed. A waterfall diagram is central to the display, with not only the satellite communications shown on the plot but information about the satellites themselves. From there the user can choose between a number of other layers of information about the satellites including their current paths, future path prediction, and a few different ways of displaying all of this information. The software also interfaces with radios via CAT control, and can even automatically correct for the Doppler shift that is so often found in satellite radio communications.

For any ham actively engaged in satellite tracking or space-based repeater communications, this tool is certainly worth trying out. Unfortunately, it’s only available for Windows currently. For those not looking to operate under Microsoft’s thumb, projects such as DragonOS do a good job of collecting up the must-have Linux programs for hams and other radio enthusiasts.

Tracking The Sun? Nah!

May 7, 2025 by 43 Comments

If you want solar power, you usually have to make a choice. You can put a solar panel in a fixed location and accept that it will only put out the maximum when the sun is properly positioned. Or, you can make the panels move to track the sun.

While this isn’t difficult, it does add cost and complexity, plus mechanical systems usually need more maintenance. According to [Xavier Derdenback], now that solar panels are cheaper than ever, it is a waste of money to make a tracking array. Instead, you can build a system that looks to the east and the west. The math says it is more cost effective.

The idea is simple. If you have panels facing each direction, then one side will do better than the other side in the morning. The post points out that a tracking setup, of course, will produce more power. That’s not the argument. However, for a given power output, the east-west solution has lower installation costs and uses less land.

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Solar Power, Logically

March 20, 2025 by 86 Comments

We’ve all seen the ads. Some offer “free” solar panels. Others promise nearly free energy if you just purchase a solar — well, solar system doesn’t sound right — maybe… solar energy setup. Many of these plans are dubious at best. You pay for someone to mount solar panels on your house and then pay them for the electricity they generate at — presumably — a lower cost than your usual source of electricity. But what about just doing your own set up? Is it worth it? We can’t answer that, but [Brian Potter] can help you answer it for yourself.

In a recent post, he talks about the rise of solar power and how it is becoming a large part of the power generation landscape. Interestingly, he presents graphs of things like the cost per watt of solar panels adjusted for 2023 dollars. In 1975, a watt cost over $100. These days it is about $0.30. So the price isn’t what slows solar adoption.

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