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galeforce
New Member
United Kingdom
73 Posts |
 Posted - 23/12/2007 : 22:25:12
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Can a PWM controller be connected direct from the wind turbine, or do you have to install another controller before it?
Reduce your C02, go Green.
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speo
Junior Member
Canada
109 Posts |
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galeforce
New Member
United Kingdom
73 Posts |
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ghurd
Junior Member
USA
304 Posts |
Posted - 24/12/2007 : 01:15:08
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"Can a PWM controller be connected direct from the wind turbine, or do you have to install another controller before it?"
Meaning 2 controllers between the turbine and battery? No.
If it does not have a dumpload, something will burn up. Eventually. When it gets windy.
Air-<something> tried it and they burned up.
There is something very wrong about that link. He doesn't speak English, know what he's selling, he copy/pasted it from China, or all of the above?
My favorite. It seems the wind turbine isn't even needed!
"12V 12A charge controller (included) maintains lead-acid batteries in fully charged state".
What is "operational photo"? Bits in the box?
G-
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speo
Junior Member
Canada
109 Posts |
Posted - 24/12/2007 : 02:35:57
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Galeforce,
The link you provided seems to be for a turbine kit, not only for a controller.
In that link, at the bottom of the page there is a schematic(right above the counter) which doesn't seem OK to me for wind applications. Looks ok for solar, but not for wind. The controller seems to be hooked in "charge controller" mode, not in diversion mode and there is no dump load.
The way it should be hooked:
- hook the turbine to the battery
- hook the solar panel to the battery
- hook any power source to the battery (hydro, pedal generator...)
- hook the controller to the battery
- hook the diversion load to the controller
Again, take a look at this link: http://www.xantrex.com/web/id/63/docserve.asp , at page 47
Every source of power gets hooked directly to the battery, like a parallel circuit and the controller too, like another parallel item. The power sources are are putting the amps directly into the battery and the controller is regulating the battery by dumping the excess to the diversion load.
Speo
www.windpulse.com |
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galeforce
New Member
United Kingdom
73 Posts |
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Gill
Starting Member
Australia
41 Posts |
Posted - 24/12/2007 : 14:07:49
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G'day galeforce,
What you have there is an Oatley Electronics - Kit K241. This Kit supersedes the popular K220 that also sold well around the world. Manufactured in Australia and you can check out their web site at http://secure.oatleyelectronics.com//product_info.php?cPath=21&products_id=175&osCsid=d4b30bb178ffc91098246a4c90045e14 where a free .PDF file is available.
Because this unit is a controller and not just a regulator, it must be positioned between the wind gen and the battery. This must be done for the back EMF braking feature if you decide to use it that way. Alternatively a dump load can be fitted if you decide to go that way(include solar lets say).
At least you can download a manual now. It's a reasonable unit for the money, Hope you have years fair winds.
Cheers... Gill |
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speo
Junior Member
Canada
109 Posts |
Posted - 24/12/2007 : 21:12:25
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Gill, what's the difference between "a controller and a regulator" ?
I noticed in the ebay link, the seller is saying "The operation of the diversion load does not drain or cycle the battery (this is not a shunt regulator)"
The way I see it, the shunt doesn't cycle the battery either. The amps will flow directly into the dump load, not into the battery.
I think the part I'm missing is diversion vs shunt or regulator vs controller? Is there a difference?
Speo
www.windpulse.com |
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Gill
Starting Member
Australia
41 Posts |
Posted - 26/12/2007 : 08:17:49
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G'day Speo,
As I understand it there is little difference when the sole purpose is to protect the battery from overcharging. However to an extent a controller, by its design, offers a little more than just regulation.
The pic below shows the basic differences.
As you see the Dump Load is always connected in shunt or in parallel with the battery. Shown is my present shunt regulator system. At night when I turn off the Hydro, the battery will drain (or cycle) through the Dump load until the lower cut-out is reached. I don't see this as a big issue but it can be used to sell controllers on eBay.
On the controller, the diode prevents any battery current flowing back through the Dump Load. This is vital in the Back EMF Braking mode to stop a total short circuit of the battery. When charging the current flows through the battery but when the set point voltage is reached, the switching diverts all the current from the battery to an independent dump load.
The choice is up to the individual as there are pro's and con's with each system.
With the regulator, the battery can cycle through the Dump load but the system is simple and generally reliable.
With the diversion controller, relying on the back EMF braking to control gen in high wind instead of say furling is a risk. Many see diversion as a way to use unwanted power, say for water heating. But this can be done with a regulator too.
From my point of view I would not hesitate to use either system as they are similar. However a better system than these is PWM (Pulse Width Mode)Regulation. The problem with the simple switching regulators/controllers is the surge of power each time they change state. The PWM system is always switching at a high rate but at a controlled duty cycle. This is gentler on the circuit than the Bang Bang switching of the other types. I do not know what is commercially available as I have just made my own.
But as I say, either type is fine for general use.
I hope that's helped.
Cheers... Gill |
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speo
Junior Member
Canada
109 Posts |
Posted - 26/12/2007 : 15:52:43
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Hi Gill,
Thanks for the detailed explanation, it's almost clear now. I got everything except this: "At night when I turn off the Hydro, the battery will drain (or cycle) through the Dump load until the lower cut-out is reached." Is cut-out the same as float voltage? If yes, why is the battery at a higher voltage than float? I am expecting that the regulator(through the dump load) will keep the voltage at the float voltage and not above, so there woill be no need to cycle after shutting down the generator.
Speo
www.windpulse.com |
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galeforce
New Member
United Kingdom
73 Posts |
Posted - 26/12/2007 : 21:34:10
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Can any of you guys look at this controller K241 and tell me if it is wired up right, as when the turbine spins the red led does not light up? Thanks for your help.
Reduce your C02, go Green. |
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Gill
Starting Member
Australia
41 Posts |
Posted - 27/12/2007 : 02:57:18
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G'day All,
galeforce,
You first. Your turbine live wire I am guessing is going directly to the battery? This is incorrect if so. Concluding yours is a DC generator, the turbine live (+) will need to go to any one of the 3 phase connections. These are between the 2 rows of 3 heat sinks carrying the rectifier Schottky diodes. If you have solar panels, connect them to one of the other phases. A second wind gen (DC) could be connected to the final phase connection. Your diversion(dump) load must at least equal the total possible input from all sources, and the total possible input must not exceed the total rating of the controller.
speo,
No, you're understanding is not correct due I expect through not understanding my term lower cut-out. I'll explain.
Lets start with charging. This is often called BOOST Charging where all current goes to the battery. This occurs until the (upper)Set Point voltage or Upper Cut-in (Float voltage) is reached. This set point is usually operator adjustable. At this voltage the Dump Load is turned ON so no further power enters the battery.
The dump load draws current and when exactly the same as the incoming power the battery voltage stays on Float(upper set point). This however would be a freak occurrence as the dump load must draw equal or more than the max output of the gen. So the norm is for the incoming power to be less than what the Dump Load is drawing.
Where does the extra power come from? It comes from the Battery. This drawing of battery power cycles the voltage lower. When the battery voltage drops, it turns OFF the Dump Load and normal(Boost) charging occurs again.
For reliability it is not wise to have this switching occurring at the same point as it would set up a fast switching oscillation. If relays were used it would burn out the contacts in super fast time.
So one way, is to add positive feed back to the circuit to create a hysteresis, which is a switching differential between ON and OFF. I call this hysteresis voltage the Lower Cut-out or Lower Set Point, though it is rarely made user adjustable.
A voltage hysteresis of 0.1v to 1 volt is typical.
Another way to stop switching oscillations is to turn ON the Dump load for a set short time, say 30 seconds. If at the end of this time the voltage is still equal to the Set point it turns ON again, and again, and again until the battery voltage is lower, there normal charging resumes. This however is still cycling the battery. It just uses a different chip.
So how does that sound? Totally confused yet?
Cheers... Gill |
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speo
Junior Member
Canada
109 Posts |
Posted - 27/12/2007 : 03:26:19
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Gill,
Thanks for clarifying it. Makes sense. I didn't realize the dump load is staying connected until the voltage drops to a certain value.
Thanks,
Speo
www.windpulse.com |
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ghurd
Junior Member
USA
304 Posts |
Posted - 27/12/2007 : 05:35:54
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I don't believe most people should try the one labled "Diversion Controlling" with a windmill, unless the hysteresis is very tight AND "Shunt Regulation" is also included as a separate circuit. Things can quickly get out of hand in either direction, with wind.
"Back EMF Breaking" is physically violent on an efficient windmill, and can be very stressful on the electrical stuff. I don't know why Oatley still makes it, especially with a 10 second delay instead of something much faster.
Gil,
I'm not sure I follow any of your logic about the PWM being easier on the circut or the surges.
Speo,
The dump load is always either On or Off with a decent controller. Some do it fast. Some do it slow.
Some of the very old designs have variable resistance due to using transistors, but the battery regulation is not very good.
G- |
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speo
Junior Member
Canada
109 Posts |
Posted - 27/12/2007 : 16:55:02
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"The dump load is always either On or Off with a decent controller. Some do it fast. Some do it slow."
G, Are there any pros / cons for fast / slow ?
Speo
www.windpulse.com |
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ghurd
Junior Member
USA
304 Posts |
Posted - 28/12/2007 : 14:20:07
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Faster is usually better and can be more accurate. But I believe it also has to do with the battery capacity and charging current.
The old circuits were very slow and cycled the battery hard. Some had hysteresis of 2+V. Some had a 30 second cycle.
G-
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PWM controller
