wind power

[niixon]

Hi,
I'm going to build an electricity generator out of wind power, I'm not an expert at all in this subject so I would need you guys to correct my mistakes please, my plan is:
1- I'm going to use a 12v DC motor
2- take the produced electricity into a DC/DC up/down regulator because the produced output will vary depending on the wind, right?
3- then from the regulator to a 12v DC battery charger.
4- now I have DC electricity stored in the battery.
is any of the above wrong?
Another question: there are a wide variety of DC motors, how can I know which one is the right for me? what factors I should put in mind when choosing my DC motor?
Thank you.

 

[Ian2008]

You don't want a dc motor what you need is a 12 volt alternator from a car.
No need for an external regulator or battery charger as it is all built in.

 

[niixon]

Thank you...I saw few different DIY wind generator youtube videos using a car alternator with built in regulator, but they used a charger controller, what kind of charger controller I would need?

 

[Astra99]

I daresay someone will be able to be more accurate, but IIRC the alternator on a car runs at around 4 times the engine speed. Usually engines will rev to 6000 rpm, so the alternator is running at 24000 rpm, and will not start charging until they achieve about 1800 rpm (600 rpm engine speed). If it is likely your wind turbine will operate well outside of the upper limit, then a gearbox of sorts will be needed. A car alternator generates 3-plase AC, which is full-wave rectified to DC by six diodes. A regulator circuit ensures that the charging current is matched to the load with a zener diode (which starts conducting to "kill" the field current at around 14.8V). As the alternator speed increases, so does the output voltage. The speed is limited by the engine driving it - it cannot rev "to hell" but a wind turbine can. So care nust be taken that an appropriate Zener, which, if necessary can handle large over-voltages, is used.

HTH

 

[niixon]

Thank you, well I think I'll stay away from the alternator, as I understand it needs strong wind to produce electricity, thus I'm sticking with a DC motor, my question is, what exactly kind of tools I need between the DC motor and my 12v batteries? charger, regulator....?
I'm doing this project because I need this electricity, I'll use it on daily bases, but unfortunately I'm not experienced in this field.

 

[ericmark]

I tried this and an alternator or dynamo needs to have permanent magnets for it to work successfully. Even re-winding the alternator I found the power required for the field resulted in batteries becoming flat. The problem is until you energise field you don't know how much power is available. I did try wiring field and rotor in series and to directly light a bulb with a zener across the bulb to stop over voltage it worked. But for a battery there is no current flow until you have 12 volt so voltage simply can't build up.

I found the old hub dynamo from a bike was best but these were discontinued so hard to find. The are despite their name alternators as are most bike dynamos. The other problem is rotating mass. If the rotating mass is small then when the wind blows the thing immediately starts to spin and wind pressure is converted into rotation power. However if the rotating mass is high it takes time to build up speed and until that speed is obtained there is a huge pressure pushing the blades back. This resulted in my space heater fan working well directly connected to an alternator but my problem was alternator was not turning fast enough. So I used a starter ring tacked to a disc and a starter pinion on the alternator giving 7:1 ratio this got the speed high enough but took too long getting up to speed so wrapped blades around the post as to much pressure forcing them back.

I copied the furlmatic design used by Rutford which is pulling the pivot point off centre and tail held by a spring once wind becomes too strong pressure on tail causes it to hinge against spring pressure and take blades out of the wind. But even that did not work with high rotating mass.

The best result was not even to try rotating the wind turbine I just placed in direction of prevailing wind it did not matter is rotated clock wise or anti clock wise it still generated. I used a hub dynamo and replaced the rim with a large loop and spoked it side to side rather than all in centre and simply wrapped with insulation tape to form the blades of wind generator and it worked.

Also tried luggage buggy cords and a rope tied to top of tree wrapped around the spindle of the hub dynamo which also worked well as tree swayed in the wind the rope ran back and to rotating the dynamo.

Problem is hub dynamo is small it needs some thing a little bigger but you need permanent magnets easy enough to turn excess power to heat or use a PWM regulator as used with solar panels but learn from my experience use something with permanent magnets.

My experiments except for tree which to be honest was some one else's experiment were all on the Falklands so loads of wind.

 

[ericmark]

Thank you, well I think I'll stay away from the alternator, as I understand it needs strong wind to produce electricity, thus I'm sticking with a DC motor, my question is, what exactly kind of tools I need between the DC motor and my 12v batteries? charger, regulator....?
I'm doing this project because I need this electricity, I'll use it on daily bases, but unfortunately I'm not experienced in this field.

I would look at a solar power regulator some are designed for both solar and wind power inputs. Too complex to build your own and not worth it anyway. They take the DC and turn to AC then transform to best ratio to extract as much power as they can and also use stage or pulse charging for the battery.

To charge a battery and at the same time use it pulse charging is best. Much depends on size of battery and charger this may seem odd but on the Falklands they tried both solar panels and wind chargers to run electric fences. The wind charger had a 15 amp max output the solar panel a 5 amp output this is back in 1980's and it was found even in the Falklands called the Windy Islands by some the solar charger worked better. Even with 1980's solar panels.

At that time MPPT and PWM regulators were not around it was a simple 2N3055 power transistor turning excess power to heat. A lead acid battery needs to be fully charged at least once a month so the idea is to charge it as quick as safe so using as much wind power as you can while it's there. This is easier with the more constant output of solar panels using the charge current as an indication of battery charge level one can charge a 50% charged battery at 16 volt but as it reaches 90% you need to reduce voltage to around 13.8 volt this is a problem with pulses of wind and also if drawing from battery while charging so the pulse works far better this gives battery a pulse of charge then stops and measures voltage then gives another pulse.

If you google Sterling generators their web site explains it well for boats but shows how it all works. Other place to look is Rutford they have been making wind generators for years likely buying the regulator from them is best option but make your own charger.

 

[bernardgreen]

Eric

Did you ever dabble with vertical axis such as Savonius and Darrieus turbines ?. I have seen a three blade Savonius driving a water pump and the ratio of calculated wind power to water lifted was high. A sucess apparently at low low RPM high torque and I wonder if it would gear up to spin an alternator.

Then there is the (apparent) dismal performance of the modern vertical axis machine on Bedford College roof ( http://www.elite-lighting.co.uk/portfolio-posts/bedford-college-2/ ) which I have never seen rotating.

Five phase stepper motors with 10 connections ( the five phase windings accessible ) can provide a good output at low RPM . They become less efficient at high RPM. A couple of 4 inch motors driven by a paddle wheel in a stream produced a few watts, enough to keep a telemetry sensor and radio link powered