Off-Grid EV Charging

August 19, 2023 by Bryan Cockfield 40 Comments

There are plenty of reasons to install solar panels on one’s home. Reducing electric bills, reducing carbon footprint, or simply being in a location without electric service are all fairly common. While some of those might be true for [Dominic], he had another motivating factor. He wanted to install a charger for his electric vehicles but upgrading the electric service at his house would have been prohibitively expensive. So rather than dig up a bunch of his neighbors’ gardens to run a new service wire in he built this off-grid setup instead.

Hooking up solar panels to a battery and charge controller is usually not too hard, but getting enough energy to charge an EV out of a system all at once is more challenging. The system is based on several 550W solar modules which all charge a lithium iron phosphate battery. The battery can output 100 A DC at 48 V which gives more than enough power to charge an EV. However there were some problems getting this much power through an inverter. His first choice let out the magic smoke when it was connected, and it wasn’t until he settled on a Growatt inverter capable of outputting 3.5 kW that the system really started to take shape.

All of this is fairly straightforward, but there’s an extra touch here that makes this project noteworthy. [Dominic] wanted to balance incoming power from the photovoltaic system to the current demands from the EVs to put less strain on the battery. An ESP32 was programmed to only send as much power to the EVs as the solar system is producing at any given time, and also includes some extra logic to make sure the battery doesn’t drain itself from the idle power requirements of the inverter. Right now the system works well but the true test will be when it goes through its first winter. Even though solar panels are more efficient at colder temperatures, if the amount of sunlight or the angle of the panels aren’t ideal there is generally much less production.

Self-Cleaning Tech Could Help Solar Panels Keep Efficiency Up

April 14, 2023 by Lewin Day 58 Comments

Solar panels are a special kind of magic — turning light into useful electrical energy. However, they don’t work nearly as well when they’re covered in dust, dirt, and grime. Conventional solutions involve spraying panels down with pure water, which is expensive and wasteful, or dry scrubbing, which can cause efficiency loss through scratching the panels. However, innovative new methods may offer useful solutions in this area, as shared by EETimes.

Researchers at MIT have explored the use of electrostatic methods to remove dust from solar panels. By creating a sufficiently strong electrostatic field, dust particles can be compelled to leap off of solar panels. The cleaning method requires no water and is entirely non-contact. It uses a motor system to pass a charged electrode past the surface of the panels, with the opposite charge applied to the panels themselves. This repels the dust from the panels and onto the moving electrode.

Other methods include the use of special “self-cleaning” glass manufactured with a laser etching technique. The method, referred to as Direct Laser Interference Patterning, or DLIP, creates microscopic features on the order of 300 nm to 30 um on the surface of the glass. The pattern creates a so-called “functional surface” from which dirt simply slides off. The laser-etched pattern has no negative impact on transparency.

If these ideas prove practical, expect them to take off quickly. Commercially viable technologies spread fast in the renewable space, as we’ve seen with the rapid uptake of floating solar farms in recent years.

Being Green, It’s A Rich Man’s Game

October 26, 2021 by Jenny List 245 Comments

It’s an old saying with an apocryphal origin: “May you live in interesting times“. We Brits are certainly living in interesting times at the moment, as a perfect storm of the pandemic, rising energy prices, global supply chain issues, and arguably the post-Brexit departure of EU-national truck drivers has given us shortages of everything from fresh vegetables in the supermarket to carbon dioxide for the food industry. Of particular concern is a shortage of automotive fuels at the filling station, and amid sometimes-aggressive queues for the pumps it’s reported that there’s a record uptick in Brits searching online for information about electric cars.

Nothing Like A Crisis To Make You Green

My VW Polo loaded for EMF 2018 — How I miss my little car, here loaded for EMF 2018.

This sudden interest in lower-carbon motoring may be driven by the queues rather than a concern for the planet, but it’s certainly true that as a culture we should be making this move if we are to have a hope of reducing our CO2 production and meeting our climate goals. A whole slew of lifestyle changes will have to be made over the coming years of which our car choices are only a part. Back to those beleaguered Brits again, a series of environmental protests have caused major disruption on the motorway network round London, not protesting against the traffic but campaigning for better home insulation.

For reasons of personal circumstance rather than principle, earlier this year I gave my trusty VW Polo to an old-Volks-nut friend and now rely on a bicycle. Living where I do within reach of everything I need it hasn’t been as challenging as I expected it to be, and aside from saving a bit of cash I know my general fitness level has gone up. Though I have less need for a car now than I used to, I intend to find myself another vehicle in due course so that I can do silly things such as throwing a Hackaday village in the back and driving halfway across Europe to a hacker camp. With an awareness that whatever I choose should be as good for the planet as I can make it then, I’ve been cruising the used-car websites to see what I can find.

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DIY Solar Ebike Goes Around The World, We Hope

October 7, 2021 by Bryan Cockfield 47 Comments

[Mark Havran] is on a mission to complete a solo trip around the world on his bicycle. For such a long and arduous trip, unsupported by anything other than what he and his bike can carry, he has devised a unique vehicle with everything he needs to accomplish his journey. This bike has plenty of things we’ve seen before, such as solar panels and an electric motor, but plenty of things that are completely novel as well.

For such long-distance trips, the preferred style of bike for most is a recumbent. This allows the rider to take a more relaxed position while riding and is much more efficient than an upright bike as well. [Mark]’s bike also uses a hub motor in the front wheel powered by a set of lithium ion battery packs. The bike also utilizes four solar panels with three charge controllers (to reduce the impacts of panel shading) laid out with three of the panels on a trailer and a single panel above the bike to give him some shade while riding. [Mark] also built solar tracking abilities into each of the two arrays, allowing the solar panels to automatically rotate around the trailer and bike to more efficiently capture sunlight than a statically-mounted set of panels would be able to. They can also be manually controlled in case of high winds.

From the video linked below, we can see a number of other added features to the bike that will enable it to make such a long trip. First, he is getting a new motor which has a number of improvements over his old one, which he put over 30,000 kilometers on. Second, there are some safety features that deserve a mention such as his lighting setup borrowed from emergency response vehicles, and even includes a fire extinguisher for any catastrophic electrical failures. Of course, if you aren’t optimizing your recumbent electric bike for long distance there are some other modifications you could make to it as well to improve its off-road abilities. Best of luck, Mark!

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Solar Fueled Emergency Power Pack

August 15, 2021 by Chris Lott 23 Comments

Heavy rainfall in Northern Europe last month caused disastrous flooding in several countries. [Daniel Jedecke] was on assignment in the North Rhine-Westphalia region of Germany during the floods and saw the damage firsthand. He was struck by the lack of emergency power, and set about the task of designing a simple, portable power pack.

[Daniel] wanted his system to be as simple and maintenance-free as possible, and well as inexpensive. He passed by the traditional solutions such as gasoline fueled generators or advanced chemistry battery packs. Instead, he settled on the ordinary car battery — they’re easy to obtain in a pinch, and he found a used 45 Ah one sitting in his basement. To keep the system portable, he decided on a single 80 W monocrystalline solar panel which comes with a smart battery charge controller. An inverter provides standard (for Germany) 240 VAC in addition to the +12 VDC output.

The whole thing, except the panel, is installed in an off-the-shelf toolbox with the pieces secured to a custom-made wood frame. We think [Daniel]’s goals were met: made from standard materials, long-lasting without excessive maintenance, portable, and providing both DC and AC outputs for everyday use. Way back in 2015 we wrote about an emergency battery pack using rechargeable drill batteries. Do you keep an emergency power pack handy in case of outages or disasters?

NASA’s Lucy Stretches Its Wings Ahead Of Trojan Trek

April 10, 2021 by Zach Zeman 4 Comments

The good news about using solar power to explore space is there are no clouds to block your sunlight. Some dust and debris, yes, but nowhere near what we have to deal with on planets. The bad news is, as you wander further and further out in the solar system, your panels capture less and less of the sunlight you need for power. NASA’s Lucy spacecraft will be dependent on every square inch, so we’re happy to hear technicians have successfully tested its solar panel deployment in preparation for an October 2021 launch.

An animation of Trojan asteroids and inner planets in orbit around the Sun. — Trojan asteroids (in green) orbit the Sun ahead of and behind Jupiter.

Lucy’s 12-year mission is to examine one Main Belt asteroid and seven so-called Trojans, which are asteroids shepherded around the Sun in two clusters at Lagrange points just ahead and behind Jupiter in its orbit. The convoluted orbital path required for all those visits will sling the spacecraft farther from the sun than any solar-powered space mission has gone before. To make up for the subsequent loss of watts per area, the designers have done their best to maximize the area. Though the panels fold up to a package only 4 inches (10 centimeters) thick, they open up to an enormous diameter of almost 24 feet (7.3 meters); which is enough to provide the roughly 500 watts required at literally astronomical distances from their power source.

Near-Earth asteroids are exciting targets for exploration partly because of the hazards they pose to our planet. Trojan asteroids, thought to be primordial remnants of the same material that formed the outer planets, pose no such danger to us but may hold insights about the early formation of our solar system. We’re already eagerly anticipating the return of OSIRIS-REx’s sample, and Hayabusa2 continues its mission after so many firsts. An extended tour of these farther-off objects will keep us watching for years to come. Check out the video embedded below for Lucy’s mission overview.

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The Dark Side Of Solar Power

December 2, 2020 by Kristina Panos 302 Comments

Everybody loves solar power, right? It’s nice, clean, renewable energy that’s available pretty much everywhere the sun shines. If only the panels weren’t so expensive. Even better, solar is now the cheapest form of electricity for companies to build, according to the International Energy Agency. But solar isn’t all apples and sunshine — there’s a dark side you might not know about. Manufacturing solar panels is a dirty process from start to finish. Mining quartz for silicon causes the lung disease silicosis, and the production of solar cells uses a lot of energy, water, and toxic chemicals.

The other issue is that solar cells have a guanteed life expectancy of about 25 years, with average efficiency losses of 0.5% per year. If replacement begins after 25 years, time is running out for all the panels that were installed during the early 2000s boom. The International Renewable Energy Agency (IREA) projects that by 2050, we’ll be looking at 78 million metric tons of bulky e-waste. The IREA also believe that we’ll be generating six million metric tons of new solar e-waste every year by then, too. Unfortunately, there are hardly any measures in place to recycle solar panels, at least in the US.

How are solar panels made, anyway? And why is it so hard to recycle them? Let’s shed some light on the subject.

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