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DIY Solar Resources?
TihSon writes "I'm building a large shed out back and I want to power the lighting using a surplus solar panel. In searching for information on how to go about this, I have found a lot of rough DIY guides for various projects that are close to my goal. But none seem to explain the reasoning and theory behind using solar panels, so hacking their project to suit my own needs could be pretty much hit-and-miss. I don't want to do a hacked-up job, and future solar projects are not out of the question, so something a bit more in-depth is required. Do you have suggestions for books or Web sites you have used to learn the ins and outs of using solar panels? Something that starts with basic theory and ends with the ability to wire a house would be perfect."
Home Power is what you want to look at. http://www.homepower.com/home/
--frank[at]unternet.org
- Dashboard solar panel intended to boost a car battery $50 AUD
- Car Battery
- 12V Light fittings intended for a caravan or similar
No, not a car battery. Get a caravan battery (or one with a similar intended use). Car batteries are designed for high current draws for a short period of time, and draining them reduces their lifetime significantly. Caravan batteries are designed to be drained, and to have a low current draw.Why not? I am off-grid with two sets of solar panels (house and well). Did the whole thing mysef with a little help from my friends at Home Power. Not a problem unless you're totally clueless, which, being a Slashdot reader, you're obviously not. Got to homepower.com, buy the CDs.
There are lots of little things with wiring that can have serious consequences.
No, there really aren't. There are a few little things and a few big things, and very few of them are arcane. Electrical systems in a typical residence are neither rocket science nor magic. A relatively good primer for residential electrical systems for a typical homeowner would be B&D Complete Guide to Home Wiring.
Where to put the ground? Please not too near a metal anything especially pipe. Why? It'll accelerate corrosion. Possibly greatly. You can screw up your neighborhood's cable this way too.
Please, please tell me you're not an electrician, nor are studying to become one. Either you WAY oversimplified to the point of making your statement meaningless or you know nothing about the ways galvanic reactions are mitigated in residential wiring. Any text on residential wiring will mention the problems and the very simple ways to avoid them ever becoming an issue.
You're right though, there are fire risks if you don't take any care with your wiring practices. Good wiring practices are amazingly simple to learn. That said, most homeowners I'm aware of who undertake electrical work for themselves do not ever bother to do so.
virtual impossibility of knowing all the minutia of one's own particular circumstance
This statement is a crock. Residential wiring is pretty straightforward for anyone willing to crack any number of simplified wiring books. Solar systems are relatively straightforward as well. I'm honestly not sure why the submitter believes that any number of other project descriptions could not be adapted to a solar shed, unless they plan on tying it into something else at a later date.
However, and it's a big one, solar intertie systems can be enormously complicated. If the submitter is planning on later tying the solar system in a shed to one in a house, said person is going about things bass-ackwards. An intertie needs to be planned from the ground up, or the likelihood of large (and costly) problems shoots through the roof.
Many things need to be answered right from the start. Am I installing a system tied to the power grid? A backup system not tied to the grid? Are there going to be batteries involved? Do I plan to convert to AC, and if so do I need clean sine-wave power? Can my charge controller handle the potential expansion of solar panels? Can additional inverters and/or charge controllers be added to the system without a great deal of hassle should the initially chosen models not handle panel additions? Am I just planning to run dedicated DC lighting circuits? These answers should take into account future plans to expand the system, as picking one particular route and then later making substantial changes to the upgrade path can dramatically increase equipment expenses.
Depending on the complexity of the situation and whether the DIYer actually intends to acquire the knowledge necessary to execute high-quality, functionally correct work, professional help may or may not be necessary.
DC power transmission over short distances is feasible. Over long distances, it isn't. Look up the Current Wars and AC power distribution. For DC, P=I^2*R=V^2/R. For AC, Prms=Irms^2*Z=Vrms^2/Z. Ignoring phase shift and comparing RMS AC quantities with DC quantities, the equations look the same. The longer the lines, the larger R, so the larger your power lost to heat. DC-DC power conversion is a modern solid-state technology (using charge pumps?) and still tends to be expensive, intolerant of transients (without proper filtering), and limited to small voltages and/or currents. AC-AC power conversion is simple, cheap, and can handle huge currents and voltages. Also, it's much harder to go from DC to AC than the other way around. Until modern solid state, in fact, there was no reliable, efficient way to convert DC to AC in any significant quantity.
If you had a shed and a house on two sides of a large property, and you wanted to put solar panels on one and bring some power to the other (perhaps it is in the shade), inverter + step-up transformer + step-down transformer + AC-to-DC is going to have a noticeable improvement in efficiency over trying to carry DC long distances. If you're generating any serious amount of power, you're also going to need some thick, thick cables to carry lo-volt hi-amp DC around in order to safely dissipate the heat, especially for wires running indoors. Even if you don't care about losses, converting to/from AC is much cheaper than replacing everything in a burned-down house.
--TheOrangeSquid Is it any wonder things seem so awry? We swim in a sea of confusion and don't have to think to survive
I recommend you check out "Home Power". It's a magazine dedicated to off-grid power production (solar, wind etc). It's a good read, very informative, and has a lot of good printed links to various resources.
It's about $4 an issue.
I dodn't work for them, but I love to read that mag.
I didn't read it as the pv panels were the sink but rather the synchronous power inverters were at fault. And there are companies like nanosolar that are getting 1 Kw per Kg of solar material, IIRC their technology doesn't require the "panels" to track the sun and they're working toward $1/watt pretty quickly.
But then there's thermal energy derived from the sun and there are nearly limitless possibilities there since the development of that carbon nanotube material that absorbs 99.8% of all light that hits it. I imagine that in many parts of the country that could be converted to heat water, create steam and drive turbines, or the new stirling engine technology if it's getting along, or even just store it underground for later use. Then one could combine that technology with the brilliant idea where they essentially put the solar-thermal collector in a vacuum so that the heat couldn't boil back off of the collector and it instead got passed quickly away to an insulated tank. It was viable over 10 months out of the year and even worked on cloudy days. I'm sure it was posted here a while back.
0x09F911029D74E35BD84156C5635688C0
Don't know where you live, but in most areas of the U.S. you legally need a permit and an inspection to perform any electrical work on residential wiring. When I say "any", I mean even down to installing an outlet or changing any type of fixed fixture. Most areas require all electrical work to be in accordance with the N.E.C. and /or the I.E.C. Further, most jurisdictions require that the person doing the residential electrical work have a valid Electrician's license. Some jurisdictions allow a homeowner to do their own electrical work, but only on their own dwelling and not on properties they own that they rent to tenants. In many jurisdictions performing unauthorized and/or unlicensed electrical work is a crime, punishable by fine and/or imprisonment.
As a licensed Master Electrician and former County building inspector, I can state with great confidence that simply reading a book such as "B&D Complete Guide to Home wiring" does not render one competent to undertake even moderately complex residential wiring projects. As I have witnessed, even seemingly straightforward tasks like stripping wires and using wire nuts can have devastating consequences when performed improperly.
To advocate that an unlicensed and inexperienced homeowner take on this type of project without adequate, licensed professional supervision is irresponsible in the extreme. No licensed electrician would advocate such irresponsible and potentially hazardous course of conduct.
I'm glad to see you quote Nanosolar. That is the company to watch. A few years back most solar R&D went into 2 camps - one camp tried to advance the underlying solar technology and mostly failed. Another camp went the route of just trying to fine-tune manufacturing (to reduce cost for mass production). That's where Nanosolar comes in. The technology behind Nanosolar in terms of energy creation is old news - but the fine tuning in the manufacturing process (super cheap "plain air" facilities) is what is so stellar about the company. Their thin-film solar panel stock is currently sold out until 2009 since several large municipal solar power generation plants bought their stock already.
Horns are really just a broken halo.
Shed lighting is pretty easy because the power requirement and the duty cycle (on vs off time) will be low, and you don't need voltage regulation. That means all you need is a largeish 12V battery (preferably rated for "deep cycle"), and a modest 12V solar panel of maybe 2-3 square feet. Test with a small setup first, and then if you want more run time (from a fully charged battery) add another battery. For more duty cycle, add another panel.
Hook the panel to the battery with a diode in series, and then hook 12V lighting (eg track lighting minus the transformer) to the battery, and you're done. Solar panels are inherently quite compatible with lead-acid charging requirements, so you don't even need charge circuitry for a small setup such as this.
If you want to power a small 110V device, you can use an inverter. You won't be running a table saw on one of those though.
Since becoming a ham several months ago, I started learning all about batteries and 12V power and while I was at some solar energy stuff. Starting with a shed project is a great idea. I am assuming you are looking to light things, not run a planer.
Oh yeah, treat all large batteries like they are bombs ready to go off. Store them outside, and if it gets below 0C then you might have to figure out how to keep them warm. Good luck with that.
Q. What is Calvin's monster snowman called? A. The Torment Of Existence Weighed Against The Horror of Non Being
I have to correct some things,
1.) no voltage regulation
a.) is bad because the more current you draw from a pv-panel the less voltage you will get thus you cannot charge a battery with
(your solution is by adding a diode to prevent this)
so a pv-battery charger and monitor is highly recommend, because lead-acid batteries need to be watched carefully you can ruin them by discharging them to their least.
b.) pv-cells have no linear characteristic, not keeping this in mind will lead to a lower effeciency, they have a
MPP - Maximum Power Point[1], the characteristics are mostly supplied with the datasheets,
also the MPP is given. So using voltage regulation you can draw more power from the cells as you could otherwise.
[1] http://en.wikipedia.org/wiki/Maximum_power_point_tracker
The second assumption is that the only thing that effects cost of an item is the energy used to produce the item. Also demonstrably false.
The third is the assumption that energy costs are uniform across the planet and that they do not change with time. Has he ever looked at his power bill?
Don Lancaster needs to take an Introductory Economics course. From this article I gather that the term "informally peer reviewed" means "read by people who agree with me and guess what, they still agree with me."
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