Solar

Solar Charge Controller Improves Efficiency of Solar Panels

Hackaday Solar Hacks -

The simplest and easiest way to charge a battery with a solar panel is to connect the panel directly to the battery. Assuming the panel has a diode to prevent energy from flowing through it from the battery when there’s no sunlight. This is fairly common but not very efficient. [Debasish Dutta] has built a charge controller that addresses the inefficiencies of such a system though, and was able to implement maximum power point tracking using an Arduino.

Maximum power point tracking (MPPT) is a method that uses PWM and a special DC-DC converter to match the impedance of the solar panel to the battery. This means that more energy can be harvested from the panel than would otherwise be available. The circuit is placed in between the panel and the battery and regulates the output voltage of the panel so it matches the voltage on the battery more closely. [Debasish] reports that an efficiency gain of 30-40% can be made with this particular design.

This device has a few bells and whistles as well, including the ability to log data over WiFi, an LCD display to report the status of the panel, battery, and controller, and can charge USB devices. This would be a great addition to any solar installation, especially if you’ve built one into your truck.

This is [Debasish]’s second entry to The Hackaday Prize. We covered his first one a few days ago. That means only one thing: start a project and start documenting it on hackaday.io


Filed under: solar hacks, The Hackaday Prize

Nocturnal Solar Light Bulb Saves Your Lungs

Hackaday Solar Hacks -

India has a bit of a problem with electricity. In fact, over 74 million rural households live without power altogether. Instead they rely on burning fuel for light — and coincidentally, inhaling harmful smoke. Not to mention fuel isn’t cheap. [Debasish Dutta] wants to change this — so he came up with yet another solar powered light that is a low-cost alternative.

It’s a very simple light made out of a cheap Tupperware container, a 2V solar panel, a white LED, a rechargeable AA or AAA battery, a photo diode and a Joule thief (voltage boosting IC). One day of charging can provide approximately 20-22 lumens for the entire night of operation. While it doesn’t seem like much, a typical kerosene lamp puts out less than half that brightness.

And with the photo diode, it automatically turns on at night, and off during the day. A coat hanger doubles as both a stand for charging, and a hook for hanging it at night.

[Dabasish] says this is just the beginning and has a website dedicated to creating green energy and sharing it with the world. Video below.


Filed under: solar hacks, The Hackaday Prize

Hippie-Redneck Solar-Heated Swimming Pool Slash Hot Tub

Hackaday Solar Hacks -

In need of a jacuzzi to complete your backyard but just don’t have the cash? Need a swimming pool for the little ones but tired of the cheap plastic ones popping and leaking all over the place? Look no further than [inexplorata]’s self-explanatory “Hippie-Redneck Solar-Heated Kiddo Swimmin’ Pool And Hot Tub“.

The pool uses a six-foot-diameter metal stock tank, provided by a neighbor. After some liberal use of JB Weld, the tank functions as a makeshift pool on the cheap, but the magic doesn’t end there. [inexplorata] found a solar thermal water heater that someone was getting rid of and snagged it to heat up the water, which is almost a necessity for most parts of the Northern Hemisphere right now.

A sump pump in a bucket handles water circulation, and [inexplorata] points out that the single water heater is more than enough to keep the water nice and warm (“hot enough to poach a rhino” is the scientific term used on the project page) so if you’ve got the means, this might be a welcome addition to the backyard! The build was posted on Reddit, the users of which had some helpful suggestions for improving the pool if you want to tackle this yourself. If you don’t have a solar thermal water heater, you could always make one of those too.


Filed under: solar hacks

Automatic Plant Care Minus the Microcontroller

Hackaday Solar Hacks -

Plants are a nice addition to most any habitat. Many of them bear flowers or attractive foliage, some of them help filter the air, and others, like aloe vera, have medicinal properties. While some plants require very little care, they all need a little moisture at some point. Overall, plant care is a bit fiddly: water them too much and you run the risk of root rot; water too little and risk death by dehydration. Hackaday alum [Kevin Darrah] would prefer not to gamble with either condition, and so in the course of a weekend’s time, he constructed a solar-powered automatic plant watering system from components he had on hand.

While he likely had a microcontroller or two lying around, he didn’t use one. His is a system of MOSFETs that trigger a motorized pump from one of those automatic bug spray bottles to draw from a reservoir and water the plant. The solar panel charges a bank of 6800µF capacitors that [Kevin] took out of an old receiver. When the desired charge is reached, the small soil sensor module is powered, assessing the moisture level. If the level is below the threshold determined by a trimmer pot, the power from the capacitor bank is dumped to the water pump and his plant gets a drink.

[Kevin]’s design deals nicely with the possible pitfalls of solar power. He’s included a 0.1µF cap to ensure latching through the system, and added a bleed resistor so that the pump is never powered unnecessarily. After running it for a couple of days, he’s already seeing moisture regulation in the soil. His complete demonstration and theory of operation is after the break. If you’re into solar power but aren’t quite ready to ditch the µC, check out this Arduino-controlled solution for thirsty tomatoes or this PIC-powered plant pacifier.


Filed under: green hacks, how-to, solar hacks

Automated Table Saw Cuts Photovoltaic Solar Cells

Hackaday Solar Hacks -

[sudarshan] is a solar hobbyist and needed a way to cut solar cells for his projects. He had previously created a rotary tool saw but manually feeding them through was sketchy at best. With just a slight wrong movement of his hand or flex in the work surface would cause the cell to break. These cells are extremely brittle and break easily. He needed a method of cutting these cells that was free from jitters and would cut in a straight line. He looked around his junk bin and found an odd solution… a scanner. Yes, the type you would scan photos in your computer with. The scanner had two critically important features, a flat surface and a carriage mechanism that moves perfectly parallel with that flat surface.

[sudarshan] made a solar cell cutting mini table saw with that scanner and made the cutting happen automatically. He mounted a motor with a diamond saw disk to the carriage, that is responsible for the cutting. The blade was positioned just high enough to poke through the plexiglass that replaced the original glass bed. A power switch turns on the cutting disk motor and an Arduino was used to move the carriage, including the cutting blade, back and forth. Two of the stock scanner buttons were reused and wired to the Arduino to keep the saw looking good.

The first few passes of the saw were done to cut a slot in the plexiglass. In order to cut a solar cell, the cell is taped to the bed with the desired cut location aligned with the slot in the plexiglass bed. Once everything is set, hit the ‘go’ button and the saw blade is slowly pushed through the cell, leaving a straight, clean cut.

 

If you’re hands are steady enough to cut solar cells without shattering them, you may be interested in this Dremel-powered solar cell saw.


Filed under: solar hacks
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