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Forum Index : Windmills : Newbie motor help
| Author | Message | ||||
| breaksbassbleep Newbie  Joined: 04/11/2008 Location: Posts: 3 |
Hi. I'm looking to construct my own wind turbine to charge up a 12V 12Ah battery (larger batteries later). i've been trying to find out what motors are the best to use in my turbine but need a little help. In this forum I've found mentioned this 1/4 rule and from what I understand I would need a motor which would generate a high enough voltage at as low RPM as possible. I've come accross this motor in my search and was wondering if this is the type of motor i would need. ebay link Thank you for any help you can provide. |
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| KiwiJohn Guru  Joined: 01/12/2005 Location: New ZealandPosts: 691 |
This type of motor is not really suitable. Any motor that has 'AC', 'capacitor start', 'induction' or 'phase' in the description is probably not suitable. Any motor that has 'DC' or 'permanet magnet' in the description and especially if it also mentions a low voltage (say, 48Volt or less) is likely worth a second look. 'Stepper motors' which are mostly a special class of permanent magnet motors are useful though most are too small except the much bigger stepper motors found in some LG and (of course) Fisher and Paykel washing machines. Generaly speaking, if joining all the wires together on a candidate motor makes it appreciably hard to turn by hand you have a good candidate for a wind generator. |
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| breaksbassbleep Newbie Joined: 04/11/2008 Location: Posts: 3 |
Thanks for the reply. What's the optimal voltage of a motor I should be aiming for. Most steppor motors i find on ebay are rated at about 4V. |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Little stepper motors are only really useful as experimental 'toys'. There is a whole topic on this site showing how to make a 'mini-mill'. As you want to charge a 12V battery I think you should be looking for a DC permanent magnet motor between about 24 and maybe 60 volts. Others may have different opinion and hope we will hear from them. |
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mister406 Newbie Joined: 20/09/2008 Location: United StatesPosts: 5 |
Hello,my question is, is it possible to over amp a battery bank.I know excess voltage will be handled by the battery itself,but I am wondering about the amperage. As you can tell I,m new to this. I have a motor that is producing roughly 42 volts around 24 amps. Will a charge controller allow this to charge batterys or is it to much? Thank you jerry |
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
In answer to your question, Yes. A motor is a unit that converts in this case electricity to motion. Do you mean a generator? Is this a windmill? There are many types of charge controller! Not much info to go on. Batteries are quite easy to break with excess current that can translate to excess voltage once the battery is charged. Gordon. become more energy aware |
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Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669 |
G'day mister406, As Gordon says, the answer is yes. Excess Amps cause a larger rise in battery temperature than is acceptable. Enough Amps and it could boil. Not good considering the acid involved. The excess heat causes fast evaporation of electrolite and reduces battery life. My battery manufacturer recommends 7% of the Amp hour rating. So for my 1000 AmpHr battery that is 70 Amps max and this is still subject to the battery temperature remaining below 50degC on all cells. Batteries like gel cells prefer a constant current and whatever the battery type, your battery manufacturers recommendation is your best guide for max life and safe use. Your typical charge controller or regulator will dump excess power when the battery voltage reaches a set voltage indicating it is charged. This is its primary function. Most do not meter temperature or Amps for the purpose of controling the rate of charge. This feature is more likely available in the high-end product range. Again let the manufacturers specs be your guide. was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| mister406 Newbie Joined: 20/09/2008 Location: United StatesPosts: 5 |
Thanks guys, yes it is a dc motor that is being used as a generator. It was going to be a windgenerator, but upon installing it ,I soon found out that there is just not enough wind here. So I converted the dc motor to be driven by another means and it produces quite well now. 2nd question, since an atomobile alt has a built-in voltage regulator, would I still need a charge controller. I have 2 high output alts being driven by a 110 volt,1750 rpm ac motor. 1 alt is used to charge a battery that feeds a small inverter to run the ac motor.the 2nd alt is used to charge a battery bank that runs a small electric heater.I realize that this is a roundabout way to produce electric but I had the stuff here so why not use it? Thanks jerry |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi jerry, the regulator in a car is not suitable without modification for charging batteries in an RE environment. The 13.8V, Nom float voltage regulated voltage output will undercharge the battery in a cyclic use pattern. Gordon. PS this arrangement sounds like a free energy machine. Out of interest, how much power is consumed from the grid when there are no loads, and the battery is fully charged? become more energy aware |
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| mister406 Newbie Joined: 20/09/2008 Location: United StatesPosts: 5 |
You are right. that is what I,m trying to build. a free energy machine.as I said, it was a windgenerator and it worked o.k. just not enough wind. I want to cut back from my heating oil costs,so, I came up with this. I am not sure of your question.if there are no loads ,why would it be running. also, that is why 1 gen/alt is dedicated for the ac motor.it would not be plugged into the grid,it would get it.,s power from an inverter.I,m simply replacing the wind with a more dependable power source I had it running yesterday on the grid power and both of the generators where producing pretty good power. I tested each gen by hooking them up individually to another {3rd} treadmill gen and it ran very well .I assume I could string as many as i want to it and thay all will generate . I also hooked up a 24 volt battery to gen #1 and it spun #2 very easily. I hooked up the volt meter and #2 was giving me 31.4 on the meter.#1 was drawing 24.6 as it turned #2 so I feel #1would produce enough to keep it running while it spins #2 does this make sense? jerry |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi jerry, I suppose I should have asked if all systems still function without the grid connected. A true free energy machine will run without an external power source, and no your explanation does not make sense. Maybe a mudmap[sketch] would help. Gordon. become more energy aware |
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