THP Semifinalist: Solar Energy System

Building a solar power installation isn’t as simple as buying a few panels, wiring them up to a battery, and putting an inverter in the mix. To get the most out of your pricey panels, you’ll want to look at something called Maximum Power Point tracking. Solar panels have an IV curve, and this changes with how much sunlight they’re getting. To get the most out of a set of cells, you need make sure you’re drawing the maximum amount of power out of your cells.

[Nathaniel]’s Solar Energy Generator does just that. It can handle up to 500 Watts, sucks power down from a bank of solar cells and spits that out to a battery. That’s not everything; the project also has a microcontroller for measuring and displaying all the pertinent info, and some terminals to plug in a few DC loads.

While the Solar Energy Generator is designed for off the grid applications, this could easily augment a home installation on the cheap. If you want more than 500 Watts or so, you’ll want to look at a larger controller, but for anything under that, [Nathan] has you covered.

Videos below.


SpaceWrencherThe project featured in this post is a quarterfinalist in The Hackaday Prize.

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Solar Energy Provides An Outlet For Hurricane-Related Woes

Hurricane season in the US Atlantic region officially began on June 1st. While [mikesoniat] is hoping for a mild one in his Gulf Coast town, he’d like to be as prepared as possible in the event of a power outage. He’s been experimenting with solar power lately, and while he’d love to go all out with some hefty system that could keep all his appliances running, solar outlethe’s not quite ready for that kind of investment. While thinking about this dream system, he noticed all the phone jacks around his house that he hasn’t used for several years. After consulting the phone company and researching the capabilities of 22-26AWG POTS copper lines, he devised a solar-powered system to provide enough power to run lights, fans, and a couple of phone chargers.

At the heart of this hack are two 12V solar panels, two 12V batteries in a weatherproof junction box, and a 100W solar charge controller.  He started by re-wiring Ma Bell’s junction box up to the panels with thermostat wire. After prying out the RJ11 jack panels all over his house, he wired in regular outlets and marked them as 12V solar to avoid confusing his house guests. He was able to find 12V LED bulbs with standard bases, so all he has to do is screw in these bulbs and plug the lamps into his solar outlets. He also installed a floodlight outside and ran all of the wiring through the floodlight box.

To soak up more sun for this or any other solar hack, try a 2-axis solar tracker.

The Phidgets Solar Powered Weather Station

weather

Yes, it’s a weather station, one of those things that records data from a suite of sensors for a compact and robust way of logging atmospheric conditions. We’ve seen a few of these built around Raspberry Pis and Arduinos, but not one built with a Phidget SBC, and rarely one that has this much thought put in to a weather logging station.

This weather station is designed to be autonomous, logging data for a week or so until the USB thumb drive containing all the data is taken back to the lab and replaced with a new one. It’s designed to operate in the middle of nowhere, and that means no power. Solar it is, but how big of a solar panel do you need?

That question must be answered by carefully calculating the power budget of the entire station and the battery, the size of the battery, and the worst case scenario for clouds and low light conditions. An amorphous solar cell was chosen for its ability to generate power from low and indirect light sources. This is connected to a 12 Volt, 110 amp hour battery. Heavy and expensive, but overkill is better than being unable to do the job.

Sensors, including temperature, humidity, and an IR temperature sensor were wired up to a Phidgets SBC3 and the coding began. The data are recorded onto a USB thumb drive plugged into the Phidgets board, and the station was visited once a week to retrieve data. This is a far, far simpler solution than figuring out a wireless networking solution, and much better on the power budget.

Via embedded lab

Solar power for your bike

solarBikeKit

After the headlight on his bike died, [Patrick] decided this was the best time to hack the remains and solve a few problems: namely a constantly drained battery from accidentally forgetting to turn the light off. He opted for a solar solution, as he already had both an Adafruit solar lithium charger and a Seeed Li-po Rider. [Patrick] picks the Adafruit board for its extra safety features like temperature sensing to prevent the cell from overheating.

The build uses 9 eBay-sourced 2V mini solar panels attached neatly on the bike’s mudflaps. Three groups of 3 panels in series provide the needed 6V into the Adafruit lithium board which safely charges a spare 900mAh Nokia phone battery from the junk drawer. [Patrick] admits this solar setup may be overkill. He decided to include a USB jack to keep his phone charged for some Google maps navigation. The Adafruit board does not step up to 5V, however, so [Patrick] tacks on a Mintyboost kit to kick the Lipo’s output up high enough to charge the phone.

Solar’s not the only alternative way to power your bike’s lights. Check out the RattleGen from earlier this year if you missed it.

Boominator solar stereo keeps the music pumping even in cloudy weather

boominator

Despite 40-some years of product improvements, boomboxes today still require a half dozen D-cell batteries and measure their life in single digit hours.  After this, the batteries get chucked in the trash. Tired of the absurd cost and quantity of batteries required in a typical boombox, reddit user [anders202] has whipped up a solution that will keep the party going and the landfills empty. Using some off-the-shelf components and some impressive woodworking skills, he created the “Boominator”.

Despite its environmentally-conscious design, this green machine packs a whallop. Using its dual 10W solar panels, it can drive four woofers and tweeters to produce an estimated 102dB of sound with power to spare.  This extra juice can be used to charge its two internal 7.2Ah batteries or a cellphone using the integrated USB charging ports.  Better still, Anders chose amorphous solar panels (as opposed to crystalline) which produce power even in cloudy weather as demonstrated during a cloudy day at the Roskilde festival in Denmark.  For more information, check out the reddit comment thread.

Video demo after the jump

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Hardware store goods and an mbed combine help solar panels track the sun

sun-tracking-solar-panels

If you have the space, and can build a tracking rig cheaply you’ll be able to get a lot more out of your solar panels. That’s because they work best when the sun’s rays are hitting them perpendicular to the surface and not at an angle. [Michael Davis] hit both of those stipulations with this mbed powered solar tracker.

At a garage sale he picked up an antenna motor for just $15. The thing was very old, but still wrapped in the original plastic. It’s beefy enough to move his panels, but he first needed a way to mount everything. After checking his angles he built a base out of wood and used galvanized water pipe as an axle. Cable clamps mate his aluminum angle bracket frame to the pipe. This frame holds the panels securely.

To track the sun he used two smaller cells which aren’t easy to pick out in this image. They are monitored by the mbed microcontroller which measures their output in order to point the assembly in the direction which has the most intense light. A couple of limit switches are included to stop the assembly when it reaches either side.

This technique of using small solar cells as the tracking sensors seems to work well. Here’s another project that took that approach.

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$4 volt meter from a dollar store pedometer

[Paulo]’s got a few solar panels on his shed, and while he does have a fairly nice setup with a battery charge controller, he found himself looking around for a panel voltmeter. Of course you can buy a panel voltmeter for under $20, but [Paulo] wanted something that fit his 4-4-4 plan; his voltmeter should cost under $4, draw less than 4mA, and last for 4 years. The jury is still out on the 4 year qualifier, but he did manage to meet his other goals by repurposing a dollar store pedometer as a voltmeter.

The pedometer in question is a very simple device. After inspecting the PCB, [Paulo] found it operates by looking at a trigger pin and incrementing the number on the display each time the circuit closed. [Paul] designed a very small PIC12F-powered circuit that reads the voltage of his batteries and triggers the pedometer’s LCD for every 10th of a volt. To display 12.6 Volts, [Paulo]’s code triggers the LCD 126 times, for example.

After wiring up the reset button so the display will go back down to zero for each new reading, [Paulo] encased his new volt meter in a plastic box. It’s not exactly a fast way of measuring voltage, but seeing as how that won’t change very fast, it’s the perfect solution for [Paulo]’s solar charger setup.