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Power Build

Hobbyist Renewable Energy? 607

Posted by ScuttleMonkey
from the green-to-go-green dept.
vossman77 writes "I was looking into renewable energy from a hobbyist perspective, maybe generating a few watts of solar or wind power, just to reduce my electric bill. But upon further review, I found out that I need a special grid-tied AC inverter that shuts off when the grid turns off (for worker safety reasons) and makes the current in-phase with the grid. These two additional features, over the cheap inverters sold at department store, make the cost upwards of $2000, but support more watts than I need. While this is fine for large-scale projects, it is out of range for a small scale hobbyist. A Google search came with some home-brew hacks at best. So, are there any Slashdotters out there doing small-scale renewable energy projects with grid-tied systems? What are other options for the hobbyist to play around with renewable energy, other than charging a cell phone?"
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Hobbyist Renewable Energy?

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  • by Anonymous Coward on Friday May 02, 2008 @12:19PM (#23276818)
    What are other options for the hobbyist to play around with renewable energy, other than charging a cell phone?

    Breed Whales, burn the oil.
    • Re: (Score:2, Funny)

      by bigdadro (452037)
      Curse you anonymous coward! You made me snarf diet pepsi all over my keyboard!
      • by mollog (841386) on Friday May 02, 2008 @01:00PM (#23277404)
        Off the top of my head, a $100 fan center could shut the power connection when the feed from the power company goes down. Attach a 24V AC transformer to the power company line and wire it to the fan center's controller. Power goes down, circuit opens.

        I can probably fabricate a circuit with an oscillator that syncs up to the 60Hz of power. After that, it's a matter of how to convert from DC to AC. It doesn't seem hard to me.
        • I'm curious about this, because I've paper-designed some similar things -- trying to use car alternators as generators by driving the field coil with AC from the grid, so the output is automatically synchronized with the grid. The problem is that since you're feeding power back into the grid, how do you detect that the grid's down? coz it won't be if you're feeding power back into it. Likewise, you seem to be doing the same sort of thing: how is your fan controller going to know whether the electricity it
          • by ahfoo (223186) on Friday May 02, 2008 @03:08PM (#23279066) Journal
            Okay, I've been interested in this for a long time and I read a good thread on the topic that I will put a copy of in this post.

            But first I would like to make a quick point which is that this is a major political obstacle to alternative energy. It's not a technical obstacle, it's a political issue because we've "deregulated" utilities by letting them regulate themselves and this is insanity. At least it is one way to ensure that we remain bound to fossil fuel solutions.

            So, on the topic of a DIY grid-tie inverter here are a few posts from a thread started by a guy looking to outsource the design.

            Some dude makes the snarky remark about why don't you just pay the price and this is the response of a user named MarkM
                  (I've reformatted a couple of his posts into a single thread for readability.)

            "Why don't you just buy one"

            BECAUSE THEY ARE WAY OVER PRICED. That was yelled a the top of my lungs.

            Solar panels cost about $4-5/Watt, inverters cost $1-2/watt. This is crazy. These grid tie inverters are no more complicated than a computer power supply which will cost you about $0.08/watt. The inherint nature of the grid tie inverters is to track the sinusoidal input and drive it to a higher voltage, thus selling the solar power on it. The IEEE 1547 require all kinds of hoops to jump thru and the inverter companies use this as an excuse to charge what they do. Again the hoops are simply jumped by a programed algorithum that monitors frequency and voltage levels. WOOOOO. I see this mans drive to find/build an inexpensive alternativ and do the gorella thing.

            The way the grid tie inverters work per the regulatory hurdles is it syncs in on the line power voltage level and sine wave siganture. If power goes down it shuts off, no harm can come to the line man. This type of statement from you or utility companies is old school old day problems stemming from someone hooking a rotatry generator or non-monitoring piece of equipmnet to the line. And if a lineman is doing as he is suposed to he grounds live wires to ground before working on a "dead line". (that's a rule)

            Utility companies have this power thing locked up and are going to be very reluctant to let small producers get in the game. Utility companies should not fear small producers they should embrace them and buy their excess power and resell it at a profit without any over head. The largest source of funds to build the power supply sytem is in the pockets of consumers: let consumers build it.

            And as far as the regulatory cost as a part of the inverter cost that to is a pile. When the cost of regulation of a certain product is spread over the number of units sold it is small. Again we have a situation of free market and what the buyer will pay. In verter builders are maximizing there profits because competition is nill. I am all for free market but too I am for some of the Chinese or Indian products to slap the US, German and Australan made manufactures into a stop gouging mode.

            The original thread is here.
            http://cr4.globalspec.com/thread/4482 [globalspec.com]

            On the general topic of grid-tie inverters you may find the following Wikipedia posts of interest. You will find the following components mentioned in the documentation for many grid-tie inverters.

            http://en.wikipedia.org/wiki/SEPIC_converter [wikipedia.org]
            http://en.wikipedia.org/wiki/Mppt [wikipedia.org]
            • by sjames (1099) on Friday May 02, 2008 @09:39PM (#23281830) Homepage

              These grid tie inverters are no more complicated than a computer power supply which will cost you about $0.08/watt.

              You realize that a grid tie inverter is the opposite of a computer power supply don't you? They don't even have to consider phase, their output doesn't HAVE a phase.

              Meanwhile, the non grid-tie inverters often output stepped voltage rather than a sinewave (and so harmonics). It's cheaper by far and good enough for many applications, but not for feeding into a big iron core transformer. They don't care about phase either. They just need to be somewhere close (ish) to 60 Hz.

              They may still be overpriced, but not by 25 times as you suggest.

            • Re: (Score:3, Informative)

              by kesuki (321456)
              tying into the grid is nice, if you're going to be producing enough power to light up 5 homes with an insanely large wind turbine, but this guy was talking about a hobbyist sized deal, where he's gone wrong is thinking he needs to tie in the grid at all. Batteries, cheap lead acid car batteries, they're really easy and cheap, and for a small project you might only need one $25 dollar battery and some cheap electronics that are quality but not certified for tying in the grid... then you can run a few lamps,
        • by Anonymous Coward on Friday May 02, 2008 @01:43PM (#23278010)
          How many city electric workers are going to agree to touch your electricity when they see some homebrew box rigged up to your breaker? I'm guessing that whatever you attach to your city's power grid has to be approved and licensed, and has to meet local electric code requirements. That probably kills most homebrew solutions.
    • by MozeeToby (1163751) on Friday May 02, 2008 @12:41PM (#23277116)
      Oh sure, that works for you people on the coast but what about the rest of us? That's why we should be focussing on cow-whale hybrids http://science.slashdot.org/article.pl?sid=08/03/13/1710223&from=rss [slashdot.org] that can live on land and still provide us with delicious whale meat and oil.
    • Re: (Score:3, Insightful)

      by bhunter736 (1283362)
      More seriously, you can collect wind and use the power for things in your garage or shop. Maybe switch one common light circuit in your house. Forget the grid tie until you are ready for the red tape that goes with it. I will be at the Make Fair in San Mateo this weekend with my Savonius Windmill and its power generating / inverter setup. I currently charge two Golf Cart batteries which have 120 Amp hours and use the power for my shop light, shop vac, and garage door opener when there is a black out. I
  • Renewable fuel (Score:3, Insightful)

    by somersault (912633) on Friday May 02, 2008 @12:20PM (#23276832) Homepage Journal

    What are other options for the hobbyist to play around with renewable energy, other than charging a cell phone?
    Well, you could grow your own crops for eating, or for bio-fuel? ;) Or have a separate circuit for your renewable power source so that it isn't connected to the mains..
    • by magarity (164372)
      Yes indeed; further, it seems the trick is to first identify what is to be powered by this project since some whole-system project is off the table. If not a cell phone, then what? Without answering that first this seems like a search for a solution in search of a problem.
      • Re: (Score:3, Interesting)

        by tha_mink (518151)

        Yes indeed; further, it seems the trick is to first identify what is to be powered by this project since some whole-system project is off the table. If not a cell phone, then what? Without answering that first this seems like a search for a solution in search of a problem.

        I think, by reading the original post, that the poster would like to leverage renewable energy to power his home. Or at least supplement the power provided to him by his local power company. I'm very interested in doing the same but in my investigation, it's going to cost upwards of $30,000 to do any serious power generation. In the summertime, I get ~$450 power bills which I'd love to offset using solar power since I've got tons of exposure at my house. The problem is, the costs before installation ar

        • Re:Renewable fuel (Score:5, Informative)

          by rs79 (71822) <hostmaster@open-rsc.org> on Friday May 02, 2008 @12:57PM (#23277330) Homepage
          Your problem is you use too much power. I had the same problem and just unplugged or rplaced everything that was overconsumptive. 700W desktop tower goes away in favouir of 45W laptop. Cordless drill that takes hours to recharge is replaced by a fast charginbh lithium ionh one. etc.

          I cut my power to 1/4 doing this. THEN went solar. Your 30K cost is now 7K.

          The OP doesbn't need a grid tie invertor. That's for selling excess power back to the power company.

          I run a sat receiver by having it plugged into a ups with a ubiquitous 7Ah SLA battery, fully charged, with two 30W solar panels hooked up directly to the battery. It just sits there and works.

          I have lots of solar panels, i just hook them up in lotrs of little autonomous systems than do one thing. Free, and forver (or until some part beaks or the sun stop shining).

          I've got a bunch of these setups for various things with various batteries and inverters.

          I can't for the life of my see how "small scale" and "grid tie" relate at all.

          If you had an 18Kw hydro plant I could see it but...
          • Re: (Score:3, Interesting)

            by SQLGuru (980662)
            Actually, isn't power tools a good case for NOT cutting the cord? Why charge up a device that you use "periodically" when you could just have one that is "always ready" and never "runs out of juice"? I have a corded drill that is more powerful than most cordless drills and doesn't have a constant draw while the battery is being charged. Sure you have to deal with load spikes, but you reduce the non-spiking load to zero.

            Maybe someone (other than me) will run the numbers on charging a 12v cordless drill vs
          • Re:Renewable fuel (Score:4, Interesting)

            by pclminion (145572) on Friday May 02, 2008 @01:33PM (#23277874)

            The OP doesbn't need a grid tie invertor. That's for selling excess power back to the power company.

            No, you need one if you want your entire house rigged for solar power. Being able to sell excess power back to the power company is just a side-effect. I started with a battery/inverter based system, and I hated it, so I went whole-house. You simply need a grid-tie inverter for that, if you aren't making enough power on your own to run your entire house.

            I've never even come close to having an excess of power to sell back to the power company. That wasn't the goal of the project.

            • Re: (Score:3, Informative)

              by TooMuchToDo (882796)
              Selling power back is indeed a side effect of grid tie. Please remember the following: A grid tie system disconnects itself from the grid when a power loss is detected. This is the most important reason to get a grid tie inverter if you intend to have it wired to the utility power lines. If this is not done, you'll electrocute line workers when they're repairing a downed wire
        • Re:Renewable fuel (Score:4, Insightful)

          by cbreaker (561297) on Friday May 02, 2008 @01:02PM (#23277426) Journal
          Certainly the 30K investment would NOT translate to $30K in the value of your home. Your home's value would probably go up the $30K regardless of the power thing.

          It would also take a very special kind of buyer to pay any significantly higher price because of it. You'd be severely limiting your potential buyer base.

          But, if the price of the home was basically on par with others in the area, you'd probably have an advantage.

          It's like swimming pools. They don't necessarily add any value to the home, and they attract only people that WANT a pool. A lot of people don't want a pool, as I suspect a lot of people wouldn't want all that extra complexity that a supplemental power generation system could introduce.

          Only spend the money if you KNOW you will stay there long enough for this to pay for itself for YOU.
      • Re:Renewable fuel (Score:5, Insightful)

        by element-o.p. (939033) on Friday May 02, 2008 @12:59PM (#23277368) Homepage
        That's kind of what the "hobbyist" label implies :)

        For a lot of hobbyists, the plan goes something like this:
        1. 1) I'd like to learn something new, like how to generate electricity from renewable sources.
        2. 2) Where can I apply this technology in a useful, but small-scale, experimental, non-critical way?
        3. 3) Search for a problem that can be solved by this solution.
        4. 4) ?
        5. 5) profit!!! (sorry, couldn't resist)
  • go 12 volt (Score:5, Insightful)

    by Jailbrekr (73837) <jailbrekr@digitaladdiction.net> on Friday May 02, 2008 @12:21PM (#23276852) Homepage
    You can try converting parts of your house to 12 or 24 volt, which would negate the need for expensive inverters and whatnot. All you'd need is a simple charging circuit for a battery (could be as simple as a diode) and then feed the 12/24 volt lights straight off it.
    • by mweather (1089505)
      I have a feeling the electrician and new appliances will cost over $2000. Good advice for those doing larger conversions, though. If not from a cost perspective, from a power loss perspective.
      • Re: (Score:3, Insightful)

        by Jailbrekr (73837)
        Low voltage requires no permits or city inspections when the work is done, hence why you can string networking cable in your home without requiring a city permit or inspector.
    • With LED lighting becoming all the rage, when are going to get a DC wiring standard for lighting in regular homes?

      All LEDs need DC, AFAIK.
      • Re: (Score:3, Informative)

        by TypoNAM (695420)
        LEDs will work perfectly fine with AC, but they'll blink/flicker at the 60Hz or so of the alternating frequency (because LEDs are diodes, as in they only allow current to flow in one direction). Now if you hook up LEDs in a series make sure that the cathods ends connect to the non-cathods ends which I hope nobody is actually doing a series of LEDs instead of parallel because if you have say three LEDs and they consume 3 volts each, you'll need 9 volts to power them to get full light output.
        • ...and because if one LED or the wire between two LEDs becomes damaged, the entire string of lights will go out.
        • Re:go 12 volt (Score:5, Interesting)

          by rs79 (71822) <hostmaster@open-rsc.org> on Friday May 02, 2008 @03:18PM (#23279188) Homepage
          " if you have say three LEDs and they consume 3 volts each, you'll need 9 volts to power them to get full light output "

          And if yoiu do 4 you can run then off a car battery. Pretty much forever.

          Plus, don't give up on dead car batteries. I have a 10 year old Optima (gel cel spiral wound deep cycle) that I killed this February starting my diesel. Although it was $180 new, 10 years is unprecedented for a battery, especially in a diesel,. But ow it's dead. It puts out a steady 9V nop matter how much you charge it. So it's useless for cars or anything 12V.

          But it'll run 1000 hi pwer LED's for about a week, and I can charge it from the sun in under half a day. And it would have got thrown out.

          Ask around golf coursds around this time of year. TGypically they may renew their golf cart bartteries and if you ask they may give you the old ones as they just dump them - thwy pay to recycle them actually.

          There's a fella near here that got 6 free, a small generator and hge lives off grid for $50/mo in electricy fro a generator he runs once a week.

          You think Tesla waited for a fucking tax rebate?

          Get to work...
      • by Gat0r30y (957941)
        Well, you could put AC over a light emitting diode, but it would flash at 60 Hz - which is a little nauseating to look at.
    • by EXMSFT (935404)
      I've thought about that... how come more people aren't thinking about it?
    • Re:go 12 volt (Score:5, Informative)

      by Technician (215283) on Friday May 02, 2008 @12:49PM (#23277250)
      You can try converting parts of your house to 12 or 24 volt, which would negate the need for expensive inverters and whatnot. All you'd need is a simple charging circuit for a battery (could be as simple as a diode) and then feed the 12/24 volt lights straight off it.

      This is a common mistake and is only good for very low power stuff. In picking a wire size people often think going from 120 volts to 12 volts only involves the math of supplying a wire 10X larger to handle the current without overheating. In a 120 volt application, you are permitted a 5% voltage drop. This isn't much as 5% of 120 volts is only about 6 volts. No big deal when running a 1200 watt portable hair dryer. If you simply size the wire to now do the same thing on 12 volts, you no longer have a 5% voltage drop. At the same current you still have a 6 volt drop with the 10X larger wire but you now lost 50% of your power in the wire. Take a hint from the pro.. Use an inverter. The 10% the inverter lost is made up by the 45% not lost in the wire. Do the math. Engineer the project.

      Either your high draw items (Microwave, toaster, blender, etc) are either within 20 inches of the battery, or you will want an inverter. With an inverter you can use standard appliances. Look for energy effecient ones.

      Another item is to ditch the grid tie for small systems. It goes down with the grid providing no security. Put the critical load on an Outback inverter. It was made just for this application. Small solar, battery maitenance, load transfer to and from solar and battery, etc. You don't have a surplus to sell to the utility, so don't connect that way. Use it to supplimant your load and reduce your total load. As a bonus, you don't have to enter a grid tie agreement with the utility where they buy your power whosale and sell it back to you retail.

      Find Outback stuff here;
      http://www.outbackpower.com/ [outbackpower.com]

      Disclaimer, I just use it. I am not otherwise involved with this company. The company has grid-tie stuff if you decide you really want it. I don't recommend it except for larger installations. This company has done a great job meeting the market. Their grid tie units are the first that I know of that operate instead of shutting down in the event of a blackout. They solved the number 1 problem with grid tie stuff.. blackouts.
      http://www.partsonsale.com/outbackgridtie.html [partsonsale.com]

      • Re:go 12 volt (Score:4, Informative)

        by DerekLyons (302214) <(fairwater) (at) (gmail.com)> on Friday May 02, 2008 @01:46PM (#23278060) Homepage

        Another item is to ditch the grid tie for small systems. It goes down with the grid providing no security. Put the critical load on an Outback inverter.

        The purpose of the grid tie isn't to provide security or to support a critical load. The purpose of a grid tie is to prevent the home power system from powering the grid when the grid goes down - if you pump power into the grid when it's down, you risk the health and life of workers trying to restore the grid.
         
        For example - A line went down that supplies my road. Before workers started repairing the line, they isolated it at the substation, rendering it safe. Without a grid tie the line remains powered from the home systems - which can kill.
         
        If you have a critical load, put it on a UPS. Don't skip the grid tie unless your home system is entirely isolated from the grid.
         
        Seriously, there's times to home brew and jury rig and save a few bucks, this isn't one of them. Do it right and don't put lives and property at risk.
    • by Roger W Moore (538166) on Friday May 02, 2008 @12:49PM (#23277254) Journal
      Err...not necessarily a good idea. If you lower the voltage your current requirements increase for the same power load. This increases the heating in the cables and thus increases the chance of an electrical fire.

      I'm sure that you can do it safely but you will need far thicker cables than a 240V system and be careful that you have good connections. Plus you will loose 10-20 times more in power transmission than before.
      • Re: (Score:3, Informative)

        by Roger W Moore (538166)
        Sorry that should be 100-400 times more power lost in transmission - it goes as current squared.
    • by Hatta (162192)
      If you're like me, you have a half a dozen game consoles in your basement with AC adapters constantly draining energy. Why not hack your old Sega Genesis to run on renewable AC power?
  • Really, $2000? (Score:3, Insightful)

    by jmauro (32523) on Friday May 02, 2008 @12:21PM (#23276856)
    If your house isn't worth $2000 then go a head jury rig something (that would probably cause your house to burn down and void your insurance to boot). Else stop screwing around, pay the $2000 and get the parts you need to do this sort of work.

    Electricity is a dangerous thing, jury rigging solutions is not an option when your safety is at risk. The device is $2000 because it must pass safety, UL, and a whole host of standards so it doesn't you know kill you or blow up the local transformer when somthing goes wrong.
    • by drinkypoo (153816)
      It's nonsense anyway, you can get it for around $1500. Dig around a little more...
    • by Ellis D. Tripp (755736) on Friday May 02, 2008 @12:45PM (#23277162) Homepage
      I would also think long and hard about criminal liability for the death or injury to utility workers who get killed because his system was backfeeding the power grid.

      Those transformers on the poles work just as well when operated backwards, stepping the 120V output from your inverter up to the 7-13 kV distribution level. Unless your inverter has enough "smarts" to isolate itself from the grid in the absence of utility power, your system will attempt to power up your part of the utility network, resulting in a severely overloaded inverter (with resultant blown fuses/smoke/fire) at the best, or a serious hazard to lineworkers at the worst.

      People HAVE been sued when lineworkers are killed/injured by improperly installed generators or PV systems that resulted in backfeed. Prosecution for criminally negligent homicide is also a possibility, especially if the prosecution can prove that you KNEW of the need for automatic isolation, but failed to provide it in order to save a buck.

      In short, use properly designed equipment, installed according to manufacturer's instructions (and get the proper permits/inspections as required), or stick with a completely isolated low voltage DC system.
    • Good point, but also consider the Return on Investment. If you do go ahead and drop the 2000 bucks - you can sell energy back to the power company (assuming you live in one of the states which permits this) usually during peak hours too. Whereas if you skip this step, you cannot sell your power back to the grid.
  • Whenever you're going on solar, you throw a switch that cuts off mains and cuts in the solar (or whatever).
  • Ugly hack (Score:3, Interesting)

    by Richard_J_N (631241) on Friday May 02, 2008 @12:22PM (#23276862)
    The easy way is just to find some subset of your electrical appliances, and arrange them with a switch, to be supplied by either your own electricity, or the grid. This is trivial to do manually, and can be automated with a relay. The downsides are:
        - at the moment of switchover, your appliance gets cut off.
        - you are always wasting some or all of your power - assuming that both supply and demand vary, and the switching is granular.
    To some extent, you can improve on this by using a UPS downstream of your switch.

    This isn't exactly an "efficient" solution, but it will work, and it's simple and cheap.
  • by Falstius (963333) on Friday May 02, 2008 @12:23PM (#23276870)
    I imagine anything you want to hook up to the grid will need to be regulated, approved and expensive. So, the alternative is a power source large enough for a single task, like running your computer, and a hefty UPS to carry you through shady spots. Plus an automatic switch over to grid power for when your batteries run down.
  • by stox (131684) on Friday May 02, 2008 @12:25PM (#23276890) Homepage
    Sorry, a home brew solution won't cut it. The power company won't allow a non-certified piece of equipment to be hooked up, nor will your homeowners insurance. The liabilities are simply not worth the savings.
    • by mweather (1089505)
      It's one thing to not electrocute the utility workers, it's quite another to ask the power company's approval. You can do one without doing the other.
  • Not cheap (Score:5, Insightful)

    by Lord_Frederick (642312) on Friday May 02, 2008 @12:26PM (#23276904)
    If going green was cheap, fossil fuels would die out on their own without incentives and subsidies.
    • Conventional sources have had decades of government subsidies. For example AFAIK, there isn't a single commercial nuke plant out there (US) that has all private insurance, the government insures them for big failure, plus the government picked up the billions of dollars (in 1950s and 60s money) tab to even develop the things in the first place. Centralized magecorpos grid electricity relies on land seizures with no compensation to the owners for powerlines. buncha stuff. Back in ye olden days (1920s) they
    • Re: (Score:3, Interesting)

      by dpilot (134227)
      Cheap is relative.

      Fossil fuels are becoming more rare, and their price is going up.
      Technology is making advances for other energy sources, so their prices are going down.

      Besides, as someone else mentions, there are already tremendous hidden subsidies in place for current sources. The same issue comes up with rail transport, because rail subsidies are explicit while air and road subsidies are hidden.
  • Keep it simple and separated. Also, DC power at 12V is much simpler and cheaper to generate and good enough for RV style lighting fixtures.

    To generate 12V DC to charge a car battery, get a 24V or 36V cooling fan for a stationary motor (for something like a large industrial compressor) and mount it on a post. Add a big diode and hook it to the battery. Simple as that.
  • by TigerNut (718742) on Friday May 02, 2008 @12:28PM (#23276934) Homepage Journal
    Tying into the grid (i.e. anything where you need to dig into the hardwired electrical system of your house) legally requires a development permit and inspection. In my location (Calgary) the homeowner can pull a permit and do the work themselves, provided it gets inspected after the fact. However, I'm pretty sure that installation of non-certified (UL or the Canadian equivalent) is strictly forbidden.

    The consequence of doing things like that without permits and/or inspection is that on the off chance that there was ever a problem, you'd be financially liable for any consequences.

    There are opportunities to do strictly off-grid stuff, or at least you could keep to the low-voltage side of things. If you have a UPS for your computer or phone/router infrastructure, you could put up a solar panel to keep the standby battery charged. To the extent that the system runs off of DC power, you could supplant the power drawn from the grid with a panel, and reduce your electrical footprint that way.

    • Without a doubt, you should use safe practices, but a homeowner/lessee have a lot of latitude. While UL equipment is the norm, there are many safe home-brew systems that can save money depending vastly on what you do with them.

      The conventional wisdom of pubs like HomePowerNews and The Mother Earth News seem to advocate understanding battery technology and inverters, and also where you're consuming juice where those consuming devices can be better used (unplugged when not in use) or replaced with more cost-e
    • If you keep the UPS plugged in AND on a solar panel to charge, won't it feed back to the grid if it loses AC coming in?
  • by netsavior (627338) on Friday May 02, 2008 @12:30PM (#23276966)
    My main cost for electricity is the Air conditioning system. Conveniently enough, I am in California, so I only need A/C when the sun is out, this makes it a perfect project for a closed solar system.

    My house is grid tied, but my wall unit Air conditioner (and roof vents, and 2 of the outlets on my porch) are 100% real time solar (with no batteries capacitors), in their own closed circuit, which is not at all grid tied. So, basically I cool my house for free, and it cost less than $1000 for everything (panels, raw materials to do the wiring myself).

    My next step is to get an outlet in the kitchen to run my next worse appliance that only needs to run part time: The washing machine, then The Dishwasher.

    Like the OP mentioned, this is a hobby thing just as much as a "green" or "money saving" thing, so I found the approach of taking the low hanging fruit (electricity I NEED to use only during the sunny time) was a favorable approach over using batteries, and expensive grid-tied adaptors/regulators/converters.
    • by Thelasko (1196535)
      Good comment:
      I would add that with heating and cooling you could always get two units. If your renewable power can't take up all of the load the grid powered one can help out. i.e. set your grid powered air conditioner thermostat a few degrees higher than your renewable one.
    • by i.r.id10t (595143)
      I'd like to do similar with my pool pump and a second set up to just power the ceiling fans I have 24/7... since when you aren't around to feel 'em, they are wasting NRG. Also need to look into a small panel for powering the pump on my outside fish pond...
    • An AC has already asked, but I'll chime in too.

      Details! I'd love to hear more about how you did this, and I'm sure that many others on here would equally appreciate any hints/information/etc you can offer.
      • Re: (Score:3, Interesting)

        by netsavior (627338)
        I replied this to a ranked 0 post so it is buried... for simplicity sake, here is the text (this is the highest ranked request for more info)

        unfortunatly I am a software developer, so I tend to resist all forms of documentation. Here is my rundown (the setup of my house means I didn't even run any wires through the house so this was so freaking simple:

        Wall unit AC (was what we used before the conversion) is on the back wall of the house) 115v 10,000 BTU unit I think they retail for ~$400-$500 (but we
    • by Thelasko (1196535) on Friday May 02, 2008 @01:49PM (#23278102) Journal
      A company called Solatube makes pre-made solar powered attic fans [solatube.com]
  • Any inverter you get should be in phase with the grid, since that's the type of power expected by your appliances. If you mean pure sine wave 60hz, that's not needed. The grid power isn't that clean. It's nice to have for battery systems, though. It'll keep your appliances quieter. That's probably your best bet is going with an off-grid RV/cabin inverter with a basic battery system. That's sill going to cost quite a bit, though. Generally speaking, a grid-intertie inverter is cheaper than batteries, but
    • by TigerNut (718742)
      The grid power isn't totally "clean" at 60 Hz, because it typically contains harmonics at multiples of the 60 Hz fundamental, but it is kept at very close to 60 Hz at a long term average. When you're tied into the grid, your generator or inverter is kept at 60 Hz because it costs a decent amount of power to stray away from the reference, but as soon as the grid reference disappears, your local power source will drift away from the reference phase. When the power comes back on, your local system has to resum
    • by Simon80 (874052)
      I'm no expert on this stuff, but it seems that you don't what what it means to be out of phase. If your system is producing an AC voltage at the same frequency and amplitude as the grid, but 180 degrees out of phase, it will cancel out the grid signal, which can only cause Terrible Things to happen. Keeping the signals in phase is definitely a must if you are going to tie the inverter and the grid together. The fact that the inverter produces the same frequency and amplitude, since this is what appliances
    • by KUHurdler (584689)
      60Hz is easy. Unless you're 180 degrees out of phase with the grid...
      so you better be N'sync.

      or in their own words...

      You might've been hurt babe, that ain't no lieeeee...
  • hot water solar (Score:5, Interesting)

    by andrew_d_allen (971588) on Friday May 02, 2008 @12:31PM (#23276980)
    It's not electrical, but solar hot water heating (with a storage tank that feeds into your main water heater) is certainly something that you can use your "hobbyist" skills to save money, that you can put together with a couple hundred dollars and some plumbing skills and basic wiring (pump & temperature switch). It can save you a bunch of money, whether or not you use electric or gas to heat your water currently.
  • Get an automatic transfer switch at the appliance level. Let's say you've got a window air conditioner unit. Get an $85 120v/30A transfer switch (http://www.pplmotorhomes.com/parts/rv-power-cords/automatic-transfer-switch.htm) hooked up to your solar-charged UPS and regular house voltage.

    When the UPS dies, the ATS will switch to regular house power.
  • Separate 12vdc (Score:3, Interesting)

    by sillivalley (411349) <sillivalley&comcast,net> on Friday May 02, 2008 @12:33PM (#23277008)
    A lot of ham radio operators set up separate 12vdc systems for powering radios and other emergency equipment. 12v deep cycle batteries plus ways of charging them -- solar panels and a solar charge controller, ac chargers, and a handful of diodes and maybe some relays so the ac operated charger only runs when needed (and there's no solar power available). Such systems are fairly simple and robust.

  • You could move a circuit or two off of the grid breaker box to their own solar/wind powered circuit(s).
    Simply install a small second breaker / fuse box and move a couple of wires. Might want to have an electrician do the work or inspect it to make sure you've covered everything. Do you want to have battery backup for night time /no wind use? That does change the options available for the inverter selection /components as they have to manage multiple inputs, charging, etc.
    Once your hobby has progressed
  • You can find 12 volt versions of "normal" incandescent bulbs at camper / trailer supply houses as well as 12 volt florescent fixtures. There's also a very wide range of automotive lamps and fixtures that run on 12 volts.

    Run these on their own completely separate circuit; you can use regular 12 volt batteries as your energy storage and charge the batteries with solar cells or a automotive alternator driven by some kind of alternate energy (steam? water wheel? windmill?) or any combination thereof. If you h

    • We're currently examining replacing a lot of lights on a boat with LEDs, because they make the battery last a lot longer before we need to kick in the generator (it's also safer because the mooring lights don't burn out). Maybe we'll add solar panels, but that's phase II.

      Your average lightbulb converts (AFAIK) about 65% of the energy into heat - which we don't need as the boat already in a hot climate :-).
  • I would suggest breaking down what you want to divert to solar and what you don't, in other words do you just want to power the fridge or air conditioner on solar, then rewiring for it. I've only setup a solar generator to supply power to a UPS, in case of blackouts, I can recharge most items.
  • by bcrowell (177657) on Friday May 02, 2008 @12:48PM (#23277230) Homepage
    If you have a pool, there are systems you can buy that run your pool pump off of photovoltaics. Pool pumps are infamous energy hogs, and you can run a pump off of DC, which cuts out the inverter. Getting rid of the inverter improves efficiency and cuts the cost of the project. This is not a grid-tied system.
  • I live in the west of England, so our climate is generally cool with a lot of cloudy days. We got solar water-heating panels put in the roof a couple of years back; it cost approx £6000, we get free hot water ~ nine months of the year (they absorb IR, so they work when it's cloudy... a vital feature for us!) They should pay for themselves in another 7 years.

    The problem with enthusiast wind generation is that power scales exponentially with the size of the turbine blades. Hence the attractivene

  • Sounds like you need to be looking at storage options, not grid-tie.
  • You can't attach a 'home-brew hack' for putting electricity back into to the power grid. It must be taken into consideration that your house would have to survive an inspection and nobody at the power company is willing to risk death because you were too cheap to provide a tested or approved solution.

    Also, if you are going to waste bandwidth on the Internet, why not give some damn details about your plan? Make it interesting at least. Right now, your ramblings seem to indicate you want free help for a poss
  • Here's what I did with my 200Watt Panel. I charged a 30Amp 12volt Battery. the panel was connected to a solar charger regulator. I designed a circuit years ago that will power an invertor from both the panels and the battery. This worked well. I used it to power my computers, back then this was a node on Fidonet. Internet connectivity was not even available for modem dialup then. I bought the panel used for $100.00. The panel lasted until I bought my house. bummer. My newphews were throwing a basebal
  • Current solar voltaic tech _will not_ save you money, it will likely be considerably more expensive than just paying for the power.

    However, if you want to do some solar stuff for a hobby (which I have done) and cost isn't the primary concern, then don't even tie to the grid; if you have to ask the questions you ask, you aren't even remotely qualified to homebrew a grid-tied inverter!

    For a hobby project, consider 12 volt stuff - perhaps use solar to run your computer (you will need to build a computer PSU th
  • Do what most people who use a generator do, install a switch in your electrical panel that allows you to plug your generator into it when needed. They typically have 2-6 switches that you redirect the feed for existing breakers to, so those selected breakers can have the option to be powered by the generator or the main line. I have the refrigerator, gas furnace fan, water pump, under-house sump pump, and the light circuits for a few rooms connected through that.

    I don't see any reason you couldn't plug s

  • talk a lot more than the people who get it done.

    http://www.otherpower.com/otherpower_systems.html [otherpower.com] is one page on a site run by a group who develop off-grid and grid-tied systems they might be a fun place to browse, also try their discussion page. Some of the stuff they get working looks like props from a mad max movie but they do work. wood fired steam engine driving a dynamo, anyone?
  • One of my personal dream projects is to run Power over Ethernet or some other DC-based power grid in the house. There are tons of AC-DC converters in most houses (computers, cell phone chargers, etc.), and it'd be a lot more efficient if we could run just one AC-DC converter with DC-DC converts on the specific devices as needed.

    This should go hand in hand with any home generator, since most such projects use large lead-acid batteries to store excess power, so you won't need an inverter at all for most app

  • So do it off the grid. Make a 12 volt circuit and buy some car appliances for your house or get a large scale inverter like a 1600 watter for like $150 and power some real appliances seperate from your home's connection to the power grid. You could run a small air conditioning unit in just your computer room hooked up to a large solar panel outside with a car battery or massive capacitor or something and it would only run when there was enough energy. That way it could cool off your hottest room and effe
  • by jsimon12 (207119) <tzzhc4NO@SPAMyahoo.com> on Friday May 02, 2008 @01:21PM (#23277696) Homepage
    Check in old issues of Home Power Magazine [homepower.com]. There were articles where people were setting up grid tie solar setups on a small scale safely without some of the expensive utility work. The articles were titled Gorilla Solar.

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