Solar

Solar Power In A Can!

Hackaday Solar Hacks -

When spending time camping, people often bring lanterns, flashlights, and the like — you might even bring along a solar charger. Instructables user [bennelson] is combining all your electrical powered needs by cramming solar power into a can.

Already designed to resist the elements, [bennelson] is using a 50cal. ammo can for a portable enclosure. Inside, he’s siliconed a 15AH, 12V lead-acid battery in the centre to maintain balance and to leave room for the wiring and storage. One cardboard mockup later, he laser-cut the top panel from 1/8″ plywood and secured a 20A solar charge controller, a four-in-one socket panel, and two banana plugs on its top face.

[bennelson] is using 12 AWG wire to match the 20A rating of the solar charge controller — including a fuse for safety — and lever lock-nut connectors to resolve some wiring complications. Industrial velcro keeps the top panel in place and easily removed should the need arise. When he’s out camping, he uses an 18V, 1A solar panel to charge, but can still use a DC power adapter to charge from the grid. Check out the full build video after the break!

[bennelson] has stuffed a few conveniences into the ammo box — a goose-neck LED light, an LED bulb and long cord to hang up over a tree branch, and a 100W AC Power inverter for any larger appliances at home or on his patio.

Be it camping, tailgating, or festivals, solar powered batteries are a handy piece of kit for any occasion.

Home Brew Solar Cells for the Chemically Curious

Hackaday Solar Hacks -

The idea of making your own semiconductors from scratch would be more attractive if it weren’t for the expensive equipment and noxious chemicals required for silicon fabrication. But simple semiconductors can be cooked up at home without anything fancy, and they can actually yield pretty good results.

Granted, [Simplifier] has been working on the method detailed in the video below for about a year, and a look at his post on copper oxide thin-film solar cells reveals a meticulous approach to optimize everything. He started with regular window glass, heated over a propane burner and sprayed with a tin oxide solution to make it conductive while remaining transparent. The N-type layer was sprayed on next in the form of zinc oxide doped with magnesium. Copper oxide, the P-type layer, was electroplated on next, followed by a quick dip in copper sulfide to act as another transparent conductor. A conductive compound of sodium silicate and graphite was layered on the back to form the electrical contacts. The cell worked pretty well — 525 mV open circuit voltage and 6.5 mA short-circuit current. Not bad for home brewed.

If you want to replicate [Simplifier]’s methods, you’ll find his ample documentation of his site. Of course, if you yearn for DIY silicon semiconductors, there’s a fab for that, too.

Imaging The Neighborhood with Solar Panels

Hackaday Solar Hacks -

Like many people who have a solar power setup at home, [Jeroen Boeye] was curious to see just how much energy his panels were putting out. But unlike most people, it just so happens that he’s a data scientist with a deep passion for programming and a flair for visualizations. In his latest blog post, [Jeroen] details how his efforts to explain some anomalous data ended with the discovery that his solar array was effectively acting as an extremely low-resolution camera.

It all started when he noticed that in some months, the energy produced by his panels was not following the expected curve. Generally speaking, the energy output of stationary solar panels should follow a clear bell curve: increasing output until the sun is in the ideal position, and then decreasing output as the sun moves away. Naturally cloud cover can impact this, but cloud cover should come and go, not show up repeatedly in the data.

Expected versus actual power output.

[Jeroen] eventually came to realize that the dips in power generation were due to two large trees in his yard. This gave him the idea of seeing if he could turn his solar panels into a rudimentary camera. In theory, if he compared the actual versus expected output of his panels at any given time, the results could be used as “pixels” in an image.

He started by creating a model of the ideal energy output of his panels throughout the year, taking into account not only obvious variables such as the changing elevation of the sun, but also energy losses through atmospheric dispersion. This model was then compared with the actual power output of his solar panels, and periods of low efficiency were plotted as darker dots to represent an obstruction. Finally, the plotted data was placed over a panoramic image taken from the perspective of the solar panels. Sure enough, the periods of low panel efficiency lined up with the trees and buildings that are in view of the panels.

We’ve seen plenty of solar hacks, but this one has to be something of a first. Usually people are more worried about maximizing efficiency or tracking the sun with them.


Filed under: green hacks, Solar Hacks

Making Solar Cells

Hackaday Solar Hacks -

We will admit that it is unlikely you have enough gear in your basement to make a solar cell using these steps. However, it is interesting to see how a bare silicon wafer becomes a solar cell. If you’ve seen ICs going through fabrication, you’ll see a lot of similarities, but there are some differences.

The process calls for a silicon wafer, some ovens, spin coaters, photolithography equipment, and a dice saw, among other things. Oh, you probably also need a clean room. Maybe you should just buy your solar cells off the shelf, but it is still interesting to see how they are made.

Modern solar cells have some extra structures to improve their efficiency, but the cells in this video are pretty garden-variety. For example, some experimental cells use multiple layers of active devices, each tuned to absorb a different wavelength of light.

If you really want to make your own, there’s another process where you can start with some copper and wind up with a kind of solar cell that uses a copper-based semiconductor material. But don’t be fooled into thinking that making the silicon variety is totally out of reach to hackers, we’ve seen [Sam Zeloof] pull it off.


Filed under: Solar Hacks
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