Off-Grid EV Charging

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.

Agrivoltaics Is A Land Usage Hack For Maximum Productivity

Land tends to be a valuable thing. Outside of some weird projects in Dubai, by and large, they aren’t making any more of it. That means as we try to feed and power the ever-growing population of humanity, we need to think carefully about how we use the land we have.

The field of agrivoltaics concerns itself with the dual-use of land for both food production and power generation. It’s all about getting the most out of the the available land and available sunlight we have.

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Dead Solar Panels Are The Hottest New Recyclables

When it comes to renewable energy, there are many great sources. Whether it’s solar, wind, or something else, though, we need a lot of it. Factories around the globe are rising to the challenge to provide what we need.

We can build plenty of new solar panels, of course, but we need to think about what happens when they reach end of life. As it turns out, with so much solar now out in the field, a major new recycling industry may be just around the corner.

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Photovoltaic Cells In LTSpice

We like to build things using real parts. But we do think the more you can model using tools like LTSpice, the less time you can spend going down dead ends. If you need to model a common component like a resistor or even an active device, most simulators have great models and you can tweak them to have realistic parasitic effects. But what if the component you want isn’t in the library or doesn’t have the fidelity you want? [FesZ] wanted to model photovoltaic cells and had to build his own model. The resulting two videos are well worth watching.

Building your own models in Spice isn’t necessarily very difficult. However, knowing exactly what to add to model different real-world effects can be challenging. The videos do a good job of showing how to mutate a simple diode into one that produces current when exposed to light.

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Solar Cells, Half Off

A company named Leap Photovoltaic claims they have a technology to create solar panels without silicon wafers which would cut production costs in half. According to [FastCompany] the cells are still silicon-based, but do not require creating wafers as a separate step or — as is more common — acquiring them as a raw material.

The process is likened to 3D printing as silicon powder is deposited on a substrate. The design claims to use only a tenth of the silicon in a conventional cell and requires fewer resources to produce, too.

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Green Roofs Could Help Improve Solar Panel Efficiency

There’s been a movement in architecture over the past couple of decades to help tie together large urban developments with plant life and greenery. We’ve seen a few buildings, and hundreds more renders, of tall skyscrapers and large buildings covered in vegetation.

The aesthetic is often a beautiful one, but the idea is done as much for its tangible benefits as for the sheer visual glory. Naturally, there’s the obvious boost from plants converting carbon dioxide into delicious, life-giving oxygen. However, greenery on the roofs of buildings could also help improve the output of solar installations, according to a recent study from Sydney, Australia.

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Better Solvents Could Lead To Cleaner, Greener Perovskite Solar Cells

Regardless of appearances, almost all scientific progress comes at a price. That which is hailed as a breakthrough technology that will save the planet or improve the lots of those living upon it almost always comes at a cost, which sometimes greatly outweighs the purported benefits of the advancement.

Luckily, though, solving these kinds of problems is what scientists and engineers live for, and in the case of the potentially breakthrough technology behind perovskite solar cells (PSCs), that diligence has resulted in a cleaner and safer way to manufacture them. We’ve covered the technology of perovskites in the past, but briefly, as related to photovoltaic cells, they’re synthetic crystals of organometallic cations bonded to a halide anion, so something like methylammonium lead tribromide. These materials have a large direct bandgap, which means a thin layer of the stuff can absorb as much solar energy as a much thicker layer of monocrystalline silicon — hence the intense interest in perovskites for cheap, easily manufactured solar cells.

The problem with scaling up PSC manufacturing has been the need for volatile and dangerous solvents to dissolve the perovskites. One such solvent, dimethylformamide (DMF), commonly used in pharmaceutical manufacturing and often a component of paint strippers, is easily absorbed through the skin and toxic to the liver in relatively low concentrations. Another common solvent, γ-butyrolactone (GBL), is a precursor to γ-hydroxybutyric acid (GHB), a common recreational club-drug known as “liquid ecstasy”.

In a recent paper, [Carys Wrosley] and colleagues at Swansea University showed that γ-valerolactone (GVL), a far less toxic and volatile solvent, could be effectively substituted for DMF and GBL in perovskite manufacturing processes. One of the most promising features of perovskites for solar cells is that the solution can be easily applied to transparent conductive substrates; the use of GVL as a solvent resulted in solar cells that were comparably efficient to cells made with the more dangerous solvents.

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