Home wind power project: multiple charge controllers?

Okay, informational question. Suppose I build a small wind turbine to power a 12 volt battery bank. I also want to get the most out of my turbine, which we'll stipulate can generate several hundred watts. Battery charge controllers seem to fall into two categories: cheap ones which only do 10-20 amps, meaning 120-240 watts, and expensive ones. Since the expensive ones are too expensive, I want to know, is it possible to use multiple charge controllers off the same turbine? For instance, if you had three 12 volt batteries, would it be possible to attach one 10 amp charge controller to each, and all three of them hooked to the common source of the wind turbine?

keeping in mind that the total of the output of the three charge controllers would be whatever your source, wind turbine, puts out. If I understand your question correctly.

I've been gathering the necessary parts to build a small wind turbine in the 800 watt range and the part I don't have yet is the charge controller due to the cost of one. I hadn't thought about using one for each battery as you're suggesting. I think I might have found my missing link.

"keeping in mind that the total of the output of the three charge controllers would be whatever your source, wind turbine, puts out. If I understand your question correctly."

I believe you do. I'm just trying to capitalize on the output as best I can--I really don't want to have a turbine putting out 300 or 400 watts, and only 120 of that making it into a battery.

"I've been gathering the necessary parts to build a small wind turbine in the 800 watt range and the part I don't have yet is the charge controller due to the cost of one. I hadn't thought about using one for each battery as you're suggesting. I think I might have found my missing link."

I have a PMM that's rated for up to 700 watts, so I'm trying to maximize how much of that is capturable at any given time. I'd hate for it to only recharge when we get a prolonged wind storm.

given to me by a friend of my son who bought a new threadmill that didn't work when he first got it home so the manufacturer sent him a new motor as he was sure it was the motor but when he went to put it in he found a wire that wasn't connected so he didn't need it and gave it to me and I'm going to make my blades from 8 inch schedule 80 pvc. the nice thing about using pipe to make the blades with they will cavitate in high winds so you don't have to worry with over speeding.
http://www.velacreations.com/makechispito.html This is basically the wind turbine I'm going to build.
I've got everything except the 8 inch pvc. I've got 3 1/2 inch pipe to make my tower out of. Where I'm at I'll only have to go 40 feet high. I'll make a hinge at the bottom that will allow me to lower the turbine for maintenance and use 5/16 cables as my guy wires.

Heres a link for some charge controllers. http://www.powerplanted.com/

If you were closer to me I'd fabricate the metal parts for you as I'm an old hand in making about anything and everything I have. I've got a small grizzly lathe/mill to make some of the parts on rather than use pipe fitting as they do at the link I included.
Hopefully this will be one of my this winter projects, I thought I was going to get to do it last winter but other things came up for me to do that I didn't get the time.
I've already got an inverter to use and I plan to use it to power our wood pellet stove and my desk lamp and what ever I'll have enough power for.

As well as making sure I haven't missed anything. I think I have a full, workable design roughed out in my head; it's just a matter now of learning to implement it.

http://www.mdpub.com/Wind_Turbine/index.html

Interestingly, this guy built his own 40 amp charge controller from scratch. I wish I were good enough at electronics to do that--or better yet, that I new someone who was good enough to do this, then sell me one for cost plus a little for labor. (Looks around hopefully)

Anyway, I don't need much. This is mostly intended as a system to supply a cabin, so the power needs aren't immense, at least at first.

I'll have to check out this link you gave here and see what I can find out too. My brother is a retired electrical engineer who has designed and built many projects though out the years so I'll have to run this past him and see what he has to say, maybe I could get him to build us both one and we could share the cost, building two would be as easy as doing one I would think.

At the link that I sent I check out the price they wanted and it wasn't really that bad, slept since then so I don't remember what it was offhand, and they were saying that the amperage could be increased by adding a relay and let the charge controller operate it so that may be the cheaper way to go.

http://homepower.com/home/

If they don't have something in classifieds that would work for you, you might be able to find someone to build it.

Hooking up several controllers in parallel is probably not a good idea. If one goes down, the others would be overpowered and quickly follow suit.

Do you mean if the wind turbines output voltage would go up too high? Using a pmm like he is talking about the load of one controller would be enough to keep the voltage produced by that pmm from rising to an unsafe limit as long as its either charging the battery or dumping the load into a resister, heating element or whatever. If that isn't the case then nothing is working anyway.
Please explain as I may be missing something

If that were the case, wouldn't using only one controller for a battery bank be just as bad, if the turbine produced more energy than the controller could account for?

in trying to say I don't have a clue as to what I'm talking about mostly. If I'm wrong I'd sure like to know though as no one person knows it all and I plan to do basically what you're planning to do because I already have an inverter that is for 12 volt dc to 120 volt ac and by using three or four batteries connected in a 12 volt configuration would be perfect for my plans and the pmm I have to make the wind turbine with. Following those links to the end that you provided it looks like either of us would be able to construct the charge controller the guy finally wound up making there at the end. I mean you and I both have to have some basic knowledge of electric or we wouldn't even be considering what we're considering. I personally think you can do it same as with me without having to get anyone else involved as Mike, the guy at the website has such good diagrams of how to make the controllers. He explains it pretty good.
I want to thank you for that link as I now feel all I have to do is get to work on building my own wind turbine. I think where he had the failure where his blades as he made them first broke and how he has them after his MacGyver instinct came through would be the better way to do it to begin with. I think I also have some 6 inch pvc that I could use for my blades and he said he used 4 inch where the crispito wind turbine that I linked to they were using 8 inch pvc which made me think that I needed to use 8 inch but now I think the 6 inch would be fine.
I think that by using a relay like he talks about would make it so a person would only need one charge controller to work on how ever big of a pmm or the numbers of batteries one was to use either in 12 or 24 volt configuration. since I already have the inverter a 12 volt configuration is what I'd go with.

Turbine > controller(s) > 12 volt battery bank > inverter. That system also has the advantage that you can use the 12 volt current directly for low-voltage stuff like powering a laptop computer, anything that runs off a car charger, or even lighting. That saves some loss relative to using the same things through an inverter. And 12 volt things are more likely to be designed for efficiency and low power consumption, since they're expected to be run off a battery.

I just want to make sure that there's nothing I'm missing in terms of the design, which is why wtmusic's comment worried me. Most of my electrical experience is with steady current DC, not with PMMs or generation. And money is tight, so I'd hate to invest in this and then fry some of my equipment. If it's really an issue, I may just end up springing a little more cash for a 30 or 40 amp charge controller. I suppose I could try to build one, but my knowledge of circuit design is less good than my general electrical skills.

I agree that the PVC blades seem wiser and more sturdy. Probably either those, or wood, would provide the most durability since they're flexible without breaking, and PVC would be easier to work.

This sure has got my enthusiasm back in gear and for that I thank you.

Pulse Width Modulation is one type of charge controller, I've never heard of 'pmm' for this or any other electronics application.

geeze, follow what we're talking about

It's an electric motor which drives the shaft using an induced electromagnetic field, acting on "permanent" (rare earth) magnets. It can also be run "backwards," turning movement of the shaft into electricity. It's the principle behind regenerative braking in electric cars, and also small wind turbines. They're popular with hobbyists because they're easy to work with, and you can buy them on eBay. Treadmill motors are popular for this sort of thing.

I'm an electronics tech, but haven't worked with anything involving electric motors, directly anyway. I believe any motor will function as a generator when the shaft is reversed, although some are obviously better suited than others for given applications.