# Car alternator on windmill -- experimenting



## budgetprepp-n

Hi guys,
My son picked up a automotive alternator type windmill and we set it up on the workbench just to see
how it worked, We just hooked up a test light and soon as it starts to move the light will come on.
Dim if its turning slow But really bright if you spin it fast. This is an automotive alternator that has been
converted for windmill use. You can get just the kit and do it yourself. And I'm not sure but I bet you
can also get the brackets and fan blade separate and build one pretty easy. This looks like an old school GM part.

The blades are fiberglass or plastic very light weight

Note we didn't get any instructions with this anyone know if a controller is needed? (I'm thinking yes)
It doesn't look like it but the blades were spinning when this picture was taken


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## Mule13

most gm alternators have a built in controller, id spin it at different rpm by hand and check with a multimeter and check the voltage outputif should stay around 14 which would be ok.


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## HuntingHawk

If its a GM its an AC/Delco. I've one I used to make a DC genset powered by a 6.5hp gas engine & had to instill a voltmeter to it. I was told it was needed to set the polarity of the output but not all of them need it.


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## GTGallop

Next question is this... Based on the size of your blades, how much minimum wind (MPH) is needed to get consistent voltage? How much wind gives you maximum voltage? And is it possible in a storm to OVER SPIN the alternator and ruin parts of it?


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## budgetprepp-n

GTGallop said:


> Next question is this... Based on the size of your blades, how much minimum wind (MPH) is needed to get consistent voltage? How much wind gives you maximum voltage? And is it possible in a storm to OVER SPIN the alternator and ruin parts of it?


 I don't have a clue,, But I am a curious as you we stuck it outside on a pole with a light on it just to see.
And I don't think it can be over spun. 
I was looking inside this alternator from the back and the built in voltage regulator is gone so I'm thinking that it is going to
need controler. I bet if it spins fast it will burn out the 12 volt bulb that we have hooked to it. On the workbench the test light
would get super scary bright just from giving it a good whip just by hand. 
The manufactures name is on one of the blades I'm going to look them up and see about getting the instructions


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## Prepadoodle

GTGallop said:


> Next question is this... Based on the size of your blades, how much minimum wind (MPH) is needed to get consistent voltage? How much wind gives you maximum voltage? And is it possible in a storm to OVER SPIN the alternator and ruin parts of it?


Size of the blades, number of blades, blade shape, blade material, and torque needed to turn the alternator all play a part in wind speed needed.

Generally speaking, bigger blades should require less wind.

Lighter blades have less mass to get going, so should require less wind.

The torque mostly depends on the size of the alternator, but can also be affected by gearing. If you gear up to get higher RPMs at the alternator, it should take more torque and higher wind speeds to start.

The actual speed needed depends on a lot of factors. Manufacturers make systems for low wind, medium wind, and high wind applications. Example...

The Primus Wind Power AIR 40 is designed for medium to high wind areas. It has 46" diameter blades, starts generating in 7 mph winds, will operate in up to 49 mph winds, will survive 110 mph winds, and uses an electronic torque regulator as overspeed protection. This is basically an electronic brake. Optimum wind speed is 10-49 mph. Costs about $900

The Coleman 600W Wind Turbine is designed for low wind speed areas. It also has 46" blades, starts at 4 mph, and can charge 12 or 24 volt batteries with its auto-detect charger. I've seen these on sale for around $500, list is about $650.

And yeah, it's very possible to spin a home-made turbine so fast it destroys itself. Commercial models usually either auto-furl, have a torque limiter (electronic or mechanical governor), or use a take down pole or tower so you can get it out of high winds.

For more info, you might want to look at...

Home Power Magazine - Wind Power Basics


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## budgetprepp-n

I found some information on this windmill. I thought it would need go faster than this


This is definitely going to need a controler


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## GTGallop

Harder to build, but you might look into the benefits of a vertical axis turbine design. They take less wind and make better use of winds that constantly change direction.


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## budgetprepp-n

GTGallop said:


> Harder to build, but you might look into the benefits of a vertical axis turbine design. They take less wind and make better use of winds that constantly change direction.


I'm thinking of letting my son take take charge on this project I got too many irons in the fire now. 
I'm trying to figure out how to wire my solar power into the house circuits,,I think I like the solar better
than the wind power.


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## HuntingHawk

That thing needs a ratio amplifier. Any type pulley system to get atleast 2:1 & 4:1 would probably best. Get higher then that & you may loose the torque to turn it. With a 2:1 means need only half the rpm to get a useable output.

I suspect that chart posted isn't accurate as its for a certain alternator/generator.

If you use bicycle sprockets & chain you will more then double your required maintenance. Pulleys with V-belt such as salvaged from a riding mower deck would be a better choice.


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## dwight55

Here is one way you could use it, . . . would not cause burned out bulbs, . . . would not be dependent upon wind speed.

Hook it to a battery bank, . . . battery bank to an inverter, . . . inverter to 110 volts for lighting, etc.

May God bless,
Dwight


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## Prepadoodle

budgetprepp-n said:


> I think I like the solar better than the wind power.


I think a hybrid solar/wind system is just about ideal. When the sun's not shining it's usually windy, so you will get something coming in, even at night. That's the way I'm gonna go too.


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## budgetprepp-n

HuntingHawk said:


> That thing needs a ratio amplifier. Any type pulley system to get atleast 2:1 & 4:1 would probably best. Get higher then that & you may loose the torque to turn it. With a 2:1 means need only half the rpm to get a useable output.
> 
> I suspect that chart posted isn't accurate as its for a certain alternator/generator.
> 
> If you use bicycle sprockets & chain you will more then double your required maintenance. Pulleys with V-belt such as salvaged from a riding
> 
> mower deck would be a better choice.


 The chart you see is for this windmill. I found the model of this and who sells it. 
It's not a car alternator anymore it now has permanent magnets inside. Just about everything inside has been replaced 
with after market windmill parts. When you turn it over by hand you can feel the magnets grabbing and releasing


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## srtayl

In most cases, alternators need to turn at 800 RPM's minimum to generate a steady current. However, this will not be it's maximum current rating; 1200+ RPM's will produce that (most of the time).

It is now converted with PMG's, cool! That means you do not have to have a battery attached to excite the rotor; raw power from EM.

Now, if this alt can produce 60amps DC at 1200 RPM, and you are going to invert to 110, remember that you will lose a lot of power to the inversion process (heat) and of course, you will have to account for the PF (power-factor loss/inefficiency) of ~20%..... now the math

- 12 VDC inverted to 110 VAC is an 8.09 dividend (110/13.6)
- 12 VDC @ 60A = 720 Watts

So... 110 VAC inverted produces 5.94 Amps (110/8.091)*.8 )) -or- 522.7 Watts (5.94*110_*.8))

These are your final numbers after accounting for a .8 power factor/ efficiency loss. For you alt, just replace the '60' amp number with your number and there you go.

Hope this helps.


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## MikeyPrepper

Rain???


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## Arizona Infidel

GTGallop said:


> Next question is this... Based on the size of your blades, how much minimum wind (MPH) is needed to get consistent voltage? How much wind gives you maximum voltage? And is it possible in a storm to OVER SPIN the alternator and ruin parts of it?


There have been engines that turn 9000 rpm and an alternator doesn't get over spun. (Remember the reduction in gearing. At 9000rpm the Alternator is spinning real fast) I doubt the wind would be able to over spin it.


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## PaulS

OK, let's clear up some misconceptions.

1. a diode doesn't require any power to prevent flow in the opposite direction - no power loss there.
2. a diode has a voltage drop of between .3 and .5 volts depending on the material with which it is made.
3. The job of the alternator is to charge the battery after the engine is started AND supply the power necessary to operate all the electrical gear on the car at the same time.
4. permanent magnet alternators do not require any outside power to generate power. It IS a generator that generates alternating current - all alternators are AC generators. They can use a small amount of power to energize the field coil (in the rotor) if they do not have a PM field.
5. a 100 amp alternator uses just slightly more than 1.7 HP to produce the full 100 amps of which it is capable. There is a direct relationship between HP and watts - you can figure it out and add 10% for losses.
6. the regulator in an alternator is a governor. It samples the OUTPUT voltage and shunts power or decreases the field strength when the output voltage goes above a certain point. There are only two wires necessary to make the alternator work. One is a wire connected to the ignition circuit - to energize the non-permanent magnet field (not required with a PM field alternator) and the wire that connects the alternator output to the battery - that one has diodes that prevent discharge as a secondary function of being a full wave bridge rectifier that turns the AC current into DC current to charge the battery and run the entire electrical system of the car.
7. Above 2400 rpm (alternator shaft speed) the alternator produces its maximum current output. If you bypass the regulator the voltage will climb to over 90 volts and the current will remain the same. When converting an automotive alternator to use in a wind generator the voltage regulator is often removed and placed at the battery to prevent losses in the wires from the alternator to the home.

The windmill will have to produce about 2 HP to power a single 100 amp alternator - you will have to use a speed multiplier (chain and sprocket, gears or a belt with the appropriate sized pulleys) to get the speed you need. From a single vertical windmill you can drive up to three automotive alternators. The old Aero-motors produce lots of torque but don't make much RPM and they are less efficient that a three bladed horizontal wind turbine of similar diameter.


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## paraquack

FWIW, my sister-in-law is a big shot at a company that makes alternators and starters. Last year they were working with a company out east that manufactures a vertical windmill and wanted my sis-I-L to come up with an alternator. I e-mailed her for any info and will share if anything came of it.


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## jimb1972

The AC current produced by the automotive alternator is converted to DC by the use of diodes IIRC, is it possible to convert one to produce AC current by removing the diodes? If so how hard would it be to regulate the voltage?


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## PaulS

It is not just a matter of regulating the voltage, with AC current you are getting 3 phase AC but the frequency (60 Hz) changes with the speed of the alternator. You can carry the AC current from the alternator into the house and connect it to the rectifier and regulator and use it to charge batteries and the run an inverter off the batteries. It would be very difficult to use the 3 phase AC from the alternator with any household electrical appliances. It simply would not be worth the cost.


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## Montana Rancher

budgetprepp-n said:


> Hi guys,
> My son picked up a automotive alternator type windmill and we set it up on the workbench just to see
> how it worked, We just hooked up a test light and soon as it starts to move the light will come on.
> Dim if its turning slow But really bright if you spin it fast. This is an automotive alternator that has been
> converted for windmill use. You can get just the kit and do it yourself. And I'm not sure but I bet you
> can also get the brackets and fan blade separate and build one pretty easy. This looks like an old school GM part.
> 
> The blades are fiberglass or plastic very light weight
> 
> Note we didn't get any instructions with this anyone know if a controller is needed? (I'm thinking yes)
> It doesn't look like it but the blades were spinning when this picture was taken


cool post, I like the pics.

My research is that unless you have a 7mph AVERAGE wind speed a wind turbine will not pay for itself.

Also keep in mind wind power has a lot of "wear" on blades and bearings and so it is not viable in a majority of places.

"Not viable" means you can spend an equal amount of money into solar and come out way way way (did I say way?) ahead of wind power.

I don't live in a viable wind area, but even if I did from what I've read, solar is a much better bang for the KW buck.


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## rickkyw1720pf

Bo Duke said:


> This post reminds me of the old Team Monte Carlo commercial with Dale Sr and Jr where Dale tells his son - I guess I don't know what I am talking about, I guess my 7 Winston Cups are plugging up my ears.
> 
> We didn't ask for a lecture on how the alternator worked, all the question was - was what it took to make it work.
> 
> I take PaulS post as being combative.
> 
> Paul, you cannot obtain 100 amps @ 14.7 volts with 1 or 2 horsepower, sorry son but you don't know what you are talking about.
> 
> Yes the initial voltage produced is a form of alternating current, that is how a two pole alternator works. The purpose of the Trio - Bridge Rectifier circuit is to convert the alternating current to a direct current. The POV of the diode is about .7 volts. So in a 4 diode set up the voltage drop of any voltage regulation circuit is about 2.8 volts!
> 
> Not many vehicles, and no GM vehicles I ever saw had permanent magnet alternators! And I worked in a junkyard for someone else for two years and I had my own junkyard for many years.. I also owned a small car stereo shop - rebuilt a lot of GM alternators, and had my own dirt track stock car team ....
> 
> , all that was asked was a simple question - will this work?
> 
> If a person was going to generate power for a bug out location they wouldn't bother producing 12 volts DC and then use an inverter since it is 60% efficient at best, which means you would throw away half of the power you produced in the inverter and wiring.


I believe on the diode bridge you actually have the a 1.4 voltage drop because only two diodes are in the circuit at any point in time or 1/2 cycle. which still represents a huge power loss 100 amp at 1.4 volts drop is 140 watt loss. A very good reason alone to try to generate the voltage at a high voltage to amp ratio. 147 volts @ 10 amps would only give you a bridge drop of 14 watts or 1/10th as much.


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## PaulS

I am not trying to be combative but I am trying to confront some bad information. I have an 8HP 5000 watt generator - that is 2 HP for each 1225 watts. The old drag racer's myth that an alternator robs the engine of 5 HP is just that - A MYTH.

The highest voltage drop that can occur across a diode is .5 volts - and that is with the old style silicone diodes. The amount of amperage flow is virtually unrestricted across a diode in that it "consumes" less than 500 mA up to its rated amp tolerance. There are six diodes in each alternator - two for each of the three legs. Each leg carries AC and the diodes carry the current into a connection with the others that coverts both sides of the AC (+ and -) to positive DC (its called a full wave bridge) so each of the three AC circuits are converted to a single DC + with the ground being the negative. 

Having been a mechanic in both the automotive and material handling industry for over 40 years I have rebuilt more than a few alternators in my time. The automotive industry doesn't use many permanent magnet alternators because is is cheaper to use an "excited" field alternator to get the high amperage output by using a coil for the field. It is also easier to regulate the power going to a field coil than it is to shunt the output on a PM alternator. 

You cannot use the three phase power output from an automotive alternator to power AC devices because the frequency changes with the RPM and most devices are single phase and need 50 - 60 cycles per second. Go beyond those frequencies and you destroy the appliance.
You could invest in a phase regulator to change the 3 phase variable Hz output from the alternator to single phase at 60 Hz but it would be prohibitively expensive and complex. It is far easier to use the alternator to generate DC current, charge batteries with it and then use a modern inverter that is 90 to 98% efficient to convert it back to AC at 60 Hz.

The answer to "can it be done?" is yes - in at least two ways. The inverter method is the least expensive and most efficient of the two that I mentioned.


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## Old Seer

budgetprepp-n said:


> I don't have a clue,, But I am a curious as you we stuck it outside on a pole with a light on it just to see.
> And I don't think it can be over spun.
> I was looking inside this alternator from the back and the built in voltage regulator is gone so I'm thinking that it is going to
> need controler. I bet if it spins fast it will burn out the 12 volt bulb that we have hooked to it. On the workbench the test light
> would get super scary bright just from giving it a good whip just by hand.
> The manufactures name is on one of the blades I'm going to look them up and see about getting the instructions


The more current it makes the harder it will turn--somewhat self adjusting.


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## Old Seer

PaulS said:


> I am not trying to be combative but I am trying to confront some bad information. I have an 8HP 5000 watt generator - that is 2 HP for each 1225 watts. The old drag racer's myth that an alternator robs the engine of 5 HP is just that - A MYTH.
> 
> The highest voltage drop that can occur across a diode is .5 volts - and that is with the old style silicone diodes. The amount of amperage flow is virtually unrestricted across a diode in that it "consumes" less than 500 mA up to its rated amp tolerance. There are six diodes in each alternator - two for each of the three legs. Each leg carries AC and the diodes carry the current into a connection with the others that coverts both sides of the AC (+ and -) to positive DC (its called a full wave bridge) so each of the three AC circuits are converted to a single DC + with the ground being the negative.
> 
> Having been a mechanic in both the automotive and material handling industry for over 40 years I have rebuilt more than a few alternators in my time. The automotive industry doesn't use many permanent magnet alternators because is is cheaper to use an "excited" field alternator to get the high amperage output by using a coil for the field. It is also easier to regulate the power going to a field coil than it is to shunt the output on a PM alternator.
> 
> You cannot use the three phase power output from an automotive alternator to power AC devices because the frequency changes with the RPM and most devices are single phase and need 50 - 60 cycles per second. Go beyond those frequencies and you destroy the appliance.
> You could invest in a phase regulator to change the 3 phase variable Hz output from the alternator to single phase at 60 Hz but it would be prohibitively expensive and complex. It is far easier to use the alternator to generate DC current, charge batteries with it and then use a modern inverter that is 90 to 98% efficient to convert it back to AC at 60 Hz.
> 
> The answer to "can it be done?" is yes - in at least two ways. The inverter method is the least expensive and most efficient of the two that I mentioned.


749 watts equals 1 HP. An alternator at 14 volts and 10 Amps is charging 140 watts. 62.5 amps X 12 volts equals 1 HP. One needs a hell of a wind to charge 62 amps. You very likely know this a but I interjected it for info to others. A 6 foot wind vane at 30mph wind equals 1/6 HP.


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## Gunner's Mate

I would ditch the plastic blade an mount a steel radiator fan blade to it, Id also google up the rpm that the alt turn versus engine rpm and use something like an old drill press belt system to change to the recommended rpm


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## sparkyprep

Old Seer said:


> 749 watts equals 1 HP. An alternator at 14 volts and 10 Amps is charging 140 watts. 62.5 amps X 12 volts equals 1 HP. One needs a hell of a wind to charge 62 amps. You very likely know this a but I interjected it for info to others. A 6 foot wind vane at 30mph wind equals 1/6 HP.


Old seer's math and concept is sound, and I agree.


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## Gunner's Mate

Great info


Old Seer said:


> 749 watts equals 1 HP. An alternator at 14 volts and 10 Amps is charging 140 watts. 62.5 amps X 12 volts equals 1 HP. One needs a hell of a wind to charge 62 amps. You very likely know this a but I interjected it for info to others. A 6 foot wind vane at 30mph wind equals 1/6 HP.


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## pheniox17

my .02 cents

simple, I like... if it's cheap enough one hooked up to a charging regulator and a deep cycle battery, will give you some "emergency power" in a pinch, wouldn't use to power a home, but a radio and a light or two, and with car "accessory chargers" the amounts of small items you could charge, as long as you can get wind.. cool!!


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## Go2ndAmend

I don't have any experience with wind power, but I really like this thread. I think a combination of solar and wind would be a great alternative energy source. I have several "off-grid" friends and most of them rely on a combination of solar and hydro through the use of a pelton (sp?) wheel. I know it sounds like a massive project, but the pelton wheel set-up is quite small and spins constantly providing the creek or stream is flowing. P.S. Thank you PaulS for your informative and excellent contribution to this thread.


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## PaulS

Go2ndAmend said:


> I don't have any experience with wind power, but I really like this thread. I think a combination of solar and wind would be a great alternative energy source. I have several "off-grid" friends and most of them rely on a combination of solar and hydro through the use of a pelton (sp?) wheel. I know it sounds like a massive project, but the pelton wheel set-up is quite small and spins constantly providing the creek or stream is flowing. P.S. Thank you PaulS for your informative and excellent contribution to this thread.


I thank you. I also believe that the more diversity that is used to generate power the better it will fill your needs. I would like to have at least three. Wind, water and solar. I would like to split the solar into heat and electrical. I use a rudimentary geo grid for cooling but would like to increase its usage to heat as well.


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## pheniox17

PaulS said:


> I thank you. I also believe that the more diversity that is used to generate power the better it will fill your needs. I would like to have at least three. Wind, water and solar. I would like to split the solar into heat and electrical. I use a rudimentary geo grid for cooling but would like to increase its usage to heat as well.


hybrid systems come with there own issues, saying that with off the grid setups, I have a huge soft spot for geothermal setups, they are expensive, but don't get the attention they deserve (unless you're watching star trek...)


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## Go2ndAmend

Nuclear would also work, but might draw unwanted attention.


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## pheniox17

Go2ndAmend said:


> Nuclear would also work, but might draw unwanted attention.


the fuel would make that option fun, if joe blow can acquire it lol


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## PaulS

A small reactor could probably be built to scale down the output. It could even have a "fail-safe" core containment. 

let's see..... 35Kw..... operating between 10 and 20Kw ........ about the same amount of plutonium as is used in a briefcase bomb should do nicely!

oops! now I'm on another darn list.


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## pheniox17

PaulS said:


> A small reactor could probably be built to scale down the output. It could even have a "fail-safe" core containment.
> 
> let's see..... 35Kw..... operating between 10 and 20Kw ........ about the same amount of plutonium as is used in a briefcase bomb should do nicely!
> 
> oops! now I'm on another darn list.


lol watch out Israel may think you're working for Iran... 
bugger I'm on that list to... what's th.....


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## Inor

PaulS said:


> A small reactor could probably be built to scale down the output. It could even have a "fail-safe" core containment.
> 
> let's see..... 35Kw..... operating between 10 and 20Kw ........ about the same amount of plutonium as is used in a briefcase bomb should do nicely!
> 
> oops! now I'm on another darn list.


If you do build such a setup can I just capture the hydrogen that is given off by the reaction? Just that would be more than enough to power my needs.


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## jimb1972

Uranium, Uranium, Uranium, the NSA and FBI should be here any minute now...


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## Go2ndAmend

Logging off and going to bed now. Dear NSA, I was just kidding.


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## pheniox17

Go2ndAmend said:


> Logging off and going to bed now. Dear NSA, I was just kidding.


go2ndamend... so that mean our deal is off???

ok ok sorry too far off topic


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## quinnbrian

Where did you get your kit from? Would be interested in buying one or two
Cheers
Brian


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## Maine-Marine

solar, water, air...all need a controller between the device and the batteries....

IE solar panel or windmill to a controller to a batteries... the lights or other devices being powered should be hooked up to a load disconnect so that a low or high load will not fry or blow the items


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## Will2

I tested a wind turbine setup still not totally confident. Here is the downlow.


if you hookup to a battry bank directly - not through a charge controller, I suggest a zener diode, otherwise the alternator can get charged from the battery not the other way around. Turbine, not fan is what you are going for.

You can use any controller but I've seen a pv controller is not recommended as pv is more about constant voltage while a wind turbine can be up and down - but a solar charger will work perhaps not as well as a wind charger.

A wind charge controller is recommended. 

The cheap one I got off ebay a handful of years ago still hasn't bee hooked up as I don't understand how the 32 gauge wires are suppose to handle a 500watt turbine. It requires that the charge go through that as part of a relay between the battery turbine and dummy load.


The zenner has to be hooked up the correct way as it is polar. It blocks the flow one way while allowing it to flow from the turbine.

If you have an exensive solid bank I suggest you use a controller, and if you use an expensive solar charger I suggest you buy a seperate wind charger.


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## bad

More power to you for building up a kit. The life span for an automotive alternator is about 2000 hours. 

Have you seen the windmills made from a used mcpherson strut? The wheel bearings are much more substantial and the strut can act as a central bearing. I have not built more than a cooling fan windmill and it ran it self to death at about 40 mph wind.


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