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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."
I someone please shed some light on this issue.
Want a DYI project?
I presume you meant a "Do Yourself In" project, which is what usually happens when people who don't know what they're doing attempt to rewire their homes.
The higher the technology, the sharper that two-edged sword.
Home Power is what you want to look at. http://www.homepower.com/home/
Hook up the battery to an inverter (to make 115V AC)
Plug light into inverter.
Why not skip this bit, and use a lower-voltage bulb? An LED array might be best, for the very low power needed.--frank[at]unternet.org
I know a bit about solar from the perspective of a cruising sailboat, in that scenario you would take a 12V solar panel, some deep cycle 12v batteries (car battery would work) and a charge controller, connect solar panel thru the charge controller to the batteries and you are done. Everything on a boat is 12VDC lights, radio, etc so running straight from battery power is easy. You could get a inverter for regular 120VAC, but it consumes your battery charge fairly quickly. For learning the parts and functions on the cheap (solar stuff can be expensive) I would suggest taking apart a solar sidewalk light and extending the wires to put the light inside your shed, and the little solar panel on the roof. To make good use of a larger solar panel you will need a larger battery bank, and probably a better charge controller. What is the output of the solar panel you want to use?
We are all just people.
Generally speaking, if you already have on-site utility power, that's going to be cheaper over the long run than solar cells.
...About that "wiring a house" business... There's not a lot of people out there who have solar+battery storage systems to run all the junk in their houses, 24 hours a day. Most of the residential systems (in the US) use solar panels with no storage batteries, the solar panels instead feed back into the electrical grid, which gets you credit off your electricity usage but usually not your total electricity bill (you still have to pay the line maintenance charge and the natural gas charge, if it exists).
But say you just want to do it 'cause it's nifty? One web forum is
http://www.solarpowerforum.net/forumVB/
You can set up a solar panel to charge a car battery, and run small things off that. Basically it goes like this: solar panel->battery regulator->battery->invertor-> small-wattage wall current appliance. Alternately, you can use 12-volt RV lights that can be run straight off the battery; there's LED lights now that don't draw squat for power. The battery regulator is a necessary device that prevents the batteries from overcharging.
The only states where these are common is southern California and Arizona, with Nevada and New Mexico being two more possible candidates. It takes a lot of sun before solar panels are even financially worth considering. Also,,, Cali and Arizona have the biggest gov't rebate programs--and if it weren't for that, NOBODY there would have a solar setup. For what they cost, it simply wouldn't make sense.
Because solar systems are so expensive, most people who want a whole-house system start by building a house that is as energy-efficient as practically possible.... So you see, there's no way to do this cheaply. Either you spend a lot of money to build a new house, or you spend a lot of money on the greater amount of solar panels to run a "typical" house off of.
...And even having done that, solar cells are generally not considered "cheaper" than utility power, even over the long-term. It will cost very close to what 30 years of utility bills would have totaled. What you get with a whole-house setup is--you're basically paying your 30 years of utility bills "up front", and you aren't dependent upon the utility company's reliability.
In certain circumstances, a solar+battery setup can be cheaper than utility power. If you buy very remote property that is literally miles from the nearest power line, the fee that the power company may charge to extend the line to your property can run into the tens of thousands of dollars.
In this rare instance, it can be cheaper to go solar.
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When I eventually move to the desert, I'd like to play with using some solar panels to run an air-cooling setup. Using solar power to run air conditioning in the desert just makes sense, and I don't know what else I'd run every day. Will probably try Peltiers first; I know their poor efficiency but the mechanical and electrical simplicity makes them attractive for a stand-alone setup, and easy to try on a small scale. In particular--they can be run basically straight off a battery, and need no invertor. The 3-phase invertor and the amount of solar panels you'd need to run a good-sized room air conditioner would cost six or seven thousand dollars, at least.
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- 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.
I have three light tubes aka light pipes in my home. They consist of an acrylic dome on the roof, a mirrored rigid pipe, and a diffuser at the end facing the inside. I often do not need to turn on lights with these suckers - very nice! Some tips - do NOT put them anywhere near a ceiling fan unless you want a disco and do NOT put them in your bedroom lest a full moon have you howling all night - yes moonlight is strong enough to light the room!
Other than that yeah go compact fluorescent or MAYBE LED. I have both and find that the LED is pretty directional and very stark white with a tinge of blue. The CF stuff lasts a good while but be careful not to get the crappy ones that take forever to light up :-( I have one of these and it pisses me off but it fits the fixture, the LED lights I bought wouldn't fit in the "can" fixture.
BTW notice that many holiday lights and tube lights are LED. These actually work pretty good for lighting some areas!
Build it, Drive it, Improve it! Hybridz.org
The fact that you think low current 120/240v is dangerous, but very high current 12/24V is safe, throughly proves the point that you do NOT understand electricity, and should certainly NOT be giving advice to others.
With amateur-installed T-Bars, I would fully expect the frame of your house to start slowly roasting itself in short order, if you're lucky, and not using quite enough current, it might not catch fire until the next heavy rain.
Automotive cables are designed to carry the current of ONE small car battery over just a meter or perhaps two. Drawing power from multiple batteries, or over much longer distances, and those cables will be getting very hot. It won't take long for the insulation to melt off, and start cooking adjacent objects.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
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
All Americans suck because they attempt to rewire their homes.
Money is the root of all evil?
Oddly enough, I'm doing the same thing: in fact I just came back inside after a day of building.
I'm building a coop for my ducks & chickens and am going to light it with power LEDs & surplus solar cells and perhaps keep the water liquid this winter using solar heating.
Solar cells are pretty straightfoward. Just think of them as batteries and you won't be too far off.
PM me if you want to run some ideas by me. I am an EE and I've done enough design work that this should be trivial. I'm also making my first attempt at a blog: http://softwarefromthefarm.blogspot.com/
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.
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.
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
Yes, and I'm sure that no licenced car mechanic would ever advocate that you do your own car repair and maintenance. Guess what - the last time I took my car to a "professional" to have new tires put on, the retard over-torqued the lugnuts so much that they warped my rotors.
What did I learn from the experience? That since there's no way for a layman to tell good professionals from bad "professionals", you may as well skip them altogether and do the work yourself. It's either that or go and pay another guy from a totally different company to check over the first guy's work.
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
I sure the parent and many slashdoters understand basic electricity, but I want to warn against just connecting a marine battery and charger together.
Improper use of these can, and have, cause fires, acid explosions, and serious burns from shorting a high current supply.
DO NOT DO THIS UNLESS YOU ARE REALLY SURE YOU UNDERSTAND WHAT YOU ARE DOING.
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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