Anyone here have small wind generator experience?

I figured this would be the best place to ask this.

I was messing around on eBay, and I ended up buying myself a permanent magnet turbine, out of a desire to play around with it, maybe make myself a windmill. It's a nice little model--if I'm doing the calculations right, it should easily run 600 watts, maybe up to 800. Catch is, the listed operating voltage is 95 volts DC. That's rather higher than I'm used to dealing with: I'd prefer something in the 12-24 volt range. I'm sure it would be perfect if I were trying to drive a 96-volt battery bank, but this is strictly a toy to me, so I'd prefer something smaller.

Hence, my questions:

I assume I'm correct that the listed voltage on the label for using it as a motor is also what it will crank out if I hook the sucker up?

Is there any easy way to transform that 95v to something more useful to me, either 12-24v DC or 110v AC? I've looked at transformers on eBay but found nothing useful. My main criteria is to do this cheaply: I absolutely can't afford any of the grid-tie inverters I've seen listed. My budget might stretch to $100 at the most.

Worst case scenario, anyone out there who'd be interested in trading for a 12-24v turbine of similar wattage?

(sorry, I don't have any experience with them) ;)

You need to check out a site like www.mrsolar.com

The one at our family farm can accept up to 120v in and charges a 48v battery bank.

We had two turbines at the farm. The one on the 40' tower produced well over 3x the charge as the one on the 20' tower.

The coasts and plains are the best places for wind, but don't discount other areas either. Often when solar isn't working, the wind is blowing and any nighttime wind is going to help keep the batteries charged and extend their life.

I also checked eBay, and the ones in my price range seem mostly designed for low-power solar applications, ten times too low for what I'm dealing with.

We certainly have no shortage of wind around here--generally, any time it's raining, you've got wind to beat the band, and in winter nothing but. That's one of the reasons I want to play with a turbine.

The smallest/least expensive charge controller from Trace (may be another name now) handles 20 amps, that's a lot more power than any 600 Watt windmill could ever put out.

Called Windbugger sells them. I used one for years on my boat, and I always had plenty of pwr.

A quick and dirty way to dump excess watts beyond the capacity of whatever you are powering is to run the output, in series, through a resistance heater of some sort -- as a temporary experimental sort of solution, plain old incandescent light bulbs might work. It is wasteful of energy, but very cheap.

With wind stuff you always have to worry about overspeed protection. You don't want to be electrocuted or have anything smacking you in the head if your improvised seat-of-the pants power control system fails -- such as might happen if a light bulb burns out.

I'm just saying you might do it that way, not that you should do it that way... Maybe you can build a hang glider out of bamboo poles and plastic tarps too, but it would probably be unwise to jump off the edge of a cliff using such a contraption.

;)

Only actually got it in the mail today. I'm going to have to get myself a voltmeter, too. Always managed to avoid needing one before.

It worked pretty well. In my experience, 600 watts of wind power requires capturing a lot of wind. How long blades do you anticipate attaching to it?

...you can run it through stepdown transformers. The reason to keep the voltage high is that DC conversion systems are more efficient at high voltages, but once your past 12 or so it's really not that big a deal. You could probably use some from PC power supplies or such -- there are enough separate windings on those that you can mix and match till you have a desirable mix, and they are made to work in that general wattage range. It really depends on how fast the blades/motor gets turned though because transformers don't work so well at very low frequencies.

That will get you lower voltage AC. Now as to how to convert it into DC, you'll need some high current rectifier diodes. Those can also be salvaged from computer power supplies or car alternators, though it's a good amount of effort to find the spec sheets for them. Those and a hefty capacitor will get you somewhat choppy DC, but the voltage will vary still based on how fast the wind is.

When you load the coils, the voltage out of them will drop. If you overload them most of the power will be used up inside the generator heating those windings, which may or may not be able to take it. If you are confident the genset won't burn up, a whole lot of medium current diodes can be stacked in series along with a resistive load to short out the coils on the high voltage side when the voltage goes over a certain value (done there in order to get away with eaiser to find lower current diodes.) But that's only something I'd recommend if you have a lot of patience.

Although it is not a very efficient way to go about things (no load matching), the cheapest way to regulate your choppy DC output is to dump it into a used "beater" battery (through yet another diode) which being a battery, has a variable resistance. The more durable the battery, the better, because this is essentially wanton battery abuse -- something that can really soak up a whole lot of current is needed, but it doesn't have to be very good at "holding a charge." That will limit the voltage swing to a range you're likely to find easier to get a real regulator/charge controller for on the secondhand market, to feed your more well-cared-for batteries. It's a cheezy hack, and you'll have to deal with venting hydrogen and fire safety issues, but it is a cheap way to get started and since this is for backyard amusement...

Of course you take any of the above suggestions at your own risk. Electricity is dangerous. Be careful.

I was thinking more of a cheap charge controller... remember he's talking less than $100 bucks here.

So you get yourself a $50 dollar (or much less) 10 amp 12 volt charge controller of some sort and figure out how to burn off 80 volts or so at 10 amps. Figure the wind won't be blowing that fast most of the time anyways. Maybe go mad scientist and use a row of 100 watt light bulbs wired in parallel. The response of things like incandescent light bulbs, electric space heaters, etc., is that their resistance increases as they get hot.

Take, for example, a 120 volt 60 watt light bulb. (Volts times amps equals watts.) When it's lit it draws half an amp. Using Ohm's law, E=IR, voltage equals amps times resistance, you get a hot resistance of 240 Ohms. But if you measure the resistance of a cold 60 Watt light bulb, it's maybe 18 Ohms.

But yeah, you should throw a bridge rectifier and a battery in there too if you happen to be using a charge controller meant for D.C. sources like solar panels that don't like choppy D.C., and this certainly isn't any way you'd want to put something together permanently. But if you are playing with it as a toy, you could just plug a space heater into it to keep it from flying off whenever you are not playing.

Hopefully the thing has some kind of built-in mechanism to keep it safe in strong winds, and any sort of tower is always a dangerous thing if it's not done right.

I love the internet, all sorts of ways to live dangerously!

Don't try this at home.

:hide:

I did some work (marketing) for a wind/solar company. In 1979. Nothin' seriously major, but I got to see how it was done. (The company folded in 1981 after the price of oil collapsed and The Gipper joined Jesus Christ in the Famous Savio(u)rs Club.)

That said, here's my Oh So Wise Advice:

Do not risk your money until you have educated yourself thoroughly.

Fortunately, with off-grid alt-energy, there is not too much for a reasonably intelligent person to learn.

What's that, Bunky? You say you already spent the dough but you don't have enough to build the rest of it? Well, you could re-sell it ... or save up over the next few monts for the rest of the stuff.

Remember, if your neighbors see that you have a working windmill, it will give them ideas. GOOD ideas. So it's not just hobby money, it's activism money. It also gives you that much-coveted-but-little-earned form of mojo called CRED. Money and mouth, as it were. Like bragging how you worked on a green energy project back in the days when The Go-Go's were still making albums, when all you did was to design some print ads and signage.

Only better.

And if you have a little green jenny on your roof, you won't have to spend any time fighting on DU with pro-nuke a**holes like that Pigwidgeon feller. All you'll have to do is point and gloat, like a vegetarian whose ex developed Mad Cow.

So, good luck! And if you do build a wind unit, post pictures!

--p!

I'll readily confess I'm probably not going to put any huge solar electric panels on my roof because it's too much bother. Nothing is easier than electricity from the grid, and if it malfunctions, it's not really my problem to get it fixed. Even if something really, really bad happenes and the electricity was out for a long, long time, it's not like we couldn't camp out in our own house just fine. We've got enough solar that we wouldn't have to use the bathrooms in the dark, and we could charge the radios and cell phones, but I'd miss the microwave oven and washing machine and coffee maker.

No matter what kind of solar system I installed, even if I could spend $20,000 on a system, I'd still consider it a toy, because if it wasn't a toy it would be an irritation. I don't trade in the sort of self righteousness that compels many people to install such things. I can go off the grid any time I want to by turning stuff off.

Besides whatever point I'm trying to make here, there are lots of very cool wind toys -- home brewed, commercial, and antique:



http://www.nationaltrust.org/magazine/archives/arc_news_2006/061206.htm

If it's just for playing around. A EE with any experience around power supplies would be able to whip you up a buck converter to drop it to 12 or 24Vdc.