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Forum Index : Windmills : Cheap Chinese 200W WTGs- maximum output?
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Loomberah Regular Member  Joined: 11/06/2008 Location: AustraliaPosts: 43 |
The other morning when the strong cold front came through, the wind picked up a lot- 10 min average around 30km/hr with gusts a bit over 50km/hr. The 200W WTG (as sold by Jaycar et al) I have up at the moment has a nominal rating of 200W, with a supposed max of 300W. Maybe it has if you use the junk regulators they come with, but I've tried 5 of them, and they were all faulty, so are best used as a source of diodes to rectify the 3phase AC only. Here is a trace of a short period from Wednesday morning showing a peak of 473W. When the wind is coming from the west at home, it's quite turbulent, as I am right at the base of a very steep 150m high hill, and there are plenty of large trees nearby, so the output varies a lot. Also after big gusts the tail furls. The pink trace is current, using the same scale as the green trace. I'm running this WTG through a BlueSky MPP regulator, which no doubt helps get the most out of it. 
Loomberah weather +solar&UV, astronomy, photography, organic farm |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5124 |
Hi Loomberah Thats a good result. I have see those cheap mills pump out over their rated pwer before. There is a article on the site about modifing the blades for berrert top end power... http://www.thebackshed.com/windmill/articles/ChineseBlades.a sp David up near Townsville has seen over 350 watts from his. A lot of the Chinese stuff is like that, a good design or core component, that was put together badly in the factory, so you just need to re-engineer it to get better results, a bit of fine tuning. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Loomberah I had simular results with the one I had up last year, as Glenn said the core is good but the rest is suspect. I had to replace the bearings as they had square balls and clean all the metal chips out of the magnets, I only tested it briefly as the wind died off for several months. I had a set of 2.4 meter blades on it ex ebay good design but terrible balance, in 8.5 ms wind it did 25 amps at 28 volts and in 15 ms gusts it was pushing out 50+ amps, the ammeter only goes to 50, so what was over that? I also tossed the regulator, as it was as good as a hip pocket in a singlet. I just use 4 bridge rectifiers two direct and two with voltage doubler caps. I locked up the furling as the blades are rated to 60 ms and if they get over that everything else will be blown away first. The furling part wasn't any good anyway as the bushes in the housing fell out after the first trial. The unit is a delta connected 24 volt nominal. I now have a 600 watt unit same brand and all the same problems internally as the 200 watt one, it doesn't perform as well as the smaller one until over 8.5 ms and then it goes wild it will hold 50 amps and gust peaks near 100 amps. I think they have real potential with a good set of blades, and a full strip down and rebuild before use. I think the main limiting factor is the blades they are supplied with as the design is cro-magnin. The magnets are very strong on the 600 watt unit, I had to use a puller to get the rotor out of the stator. At the moment I am trialing a set of high speed blades 10 blade but only 60" diameter and I think that's the problem with reduced output as not enough swept area. Glad to hear of your success with yours. All the best Bob Foolin Around |
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| jimovonz Newbie  Joined: 09/04/2007 Location: Posts: 7 |
I imported and tested a number of these turbines some years ago with a view to selling them commercially. Out of the box they were next to useless but I thought that with a little modification they might have potential. As you have found, the controller that shipped with them was next to useless. Two out of three were DOA. I binned these and made my own. With all the usual modifications (bearings, balancing, blade mods, controller etc) they aren't too bad and do quite well in low winds. I posted on the Fieldlines board about some of the testing I did: here Direct connected to a 12v battery they managed well over 300W, however the most I could get out of mine using a DC/DC buck converter (my attempt at MPPT) was approaching 600W. Admittedly this only occurred on one particular sweeping bend on the road I used to test the turbines (trailer mounted - see the link). This particular right sweeping bend seemed to be perfectly formed such that if I accelerated through it the forces on the turbine stopped the furling from operating thereby over revving the turbine (10-15 seconds max) to produce these figures :) |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Jim I think you hit the nail on the head with your corner and stopping it furling. The results I have are all without furling, so it is driven faster and really works well, I wouldn't do it with the original blades though, as they develop fatigue cracks after a few hours but with the new high speed blades they really spin up and produce power. It is a shame that they stuffed up a good little turbine with poor workmanship and controls. All the best Bob Foolin Around |
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| jimovonz Newbie Joined: 09/04/2007 Location: Posts: 7 |
I can't find the exact figures right now but even with a step down converter attached, the efficiency at this level of output was not good - if it were maintained for any significant period I don't imagine it would last long.... |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Jim It would certainly overheat with long term high winds, however as it is only gusts that get high output the average is much lower, I didn't find any sign of heated windings when I checked it out. I checked the wire size at the time and according to that, it would do 1000 watts within the wire spec. That's the 200 watt one, the 600 watt one worked out at 1800 watt, both in delta configuration. I will get the 200 watt one up again later this year and see if it does burn out. All the best Bob Foolin Around |
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Loomberah, the best way to confirm the mill is performing well is to monitor the input voltage of the Maximizer, with the associated current. The input voltage to the maximizer should indicate rpm with some correlation. The output power can be calculated and plotted against this voltage. I would think that if the result approximates somewhere between a squared and cubic relation that the windmill would be tracking the wind reasonably well. If the output power increases by a factor of 8 for a doubling of the windmill output voltage, then this is the ideal relation. My windmill analyzer program plots this type of relation with the windmill rpm. The program you have seems to only have a timebase x axis, so you may need to spreadsheet the data. I think the 12V/24V chinese mills have been recorded at producing over 700W, with original blades[balanced of course], but not into a battery load. I had one of these mills for a trial, but the blade noise was a problem. Gordon. PS I still have one of the so called dud controllers. Mine is the one with the extruded heatsink that uses armature shorting instead of the dump load. become more energy aware |
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| Loomberah Regular Member Joined: 11/06/2008 Location: AustraliaPosts: 43 |
Near 500W from a rated 200W mill with crappy blades tells me it is working well enough 
I'm making some new aerofoil blades from plywood for it... but finding a spare day to finish them is the hard bit. I am away from home a lot, and there is plenty of higher priority stuff to do when I am home. The plot I posted is only the basic plot from the data logger software, I could plot input V and A vs output V and A on an XY graph if I needed to measure them. I am planning to test the alternator from one of these (I have a few) on my hydro power system sometime soon, and put the 500W one up a 17m tower when I finish the blades for it. Loomberah weather +solar&UV, astronomy, photography, organic farm |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Loomberah, The data you have published shows that the windmill does not seem to load optimally, even though there seems to be good power at the top end. The current tells me that the windmill seems to favour top end power. The maximizer seems to give good results, but I think the low end is missing. Without other data, this is speculation though. I have many years of my own windmill and weather station data now, and this part of your data, and the flat topping of many of the peaks suggests to me that the mill if furling heavily at the top end, and the higher peak was a result of the windmill just happening to hook into and out of furl, with the resultant characteristic current trace. 
In the 10 minute time segment, there are times when the current drops close to zero. You say the windmill furls when this happens. On my own windmills with a maximizer, the current does not drop to zero unless the wind stops [drops to under 5kph]. My own windmills are slightly higher than my house, and are in a lot of turbulence as well from other buildings close by. The main thing is that you are happy with the way the windmill works. BTW I am not sure if plywood is the way to go for blades. Laminated sections rather than plywood would be a better option. Gordon. become more energy aware |
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| Loomberah Regular Member Joined: 11/06/2008 Location: AustraliaPosts: 43 |
The mill is actually much lower than the trees to its West side, so the air is very turbulent, hard to avoid when at the base of a very steep hill, without a 50m tower. Its on a 10m tower now. It starts producing power at 12-15km/hr, depending on direction/how turbulent it is, and turbulent air has much less power in it. The power drops to near zero after a big gust are generally due to furling and/or lulls, and it does sometimes stick in the furled position for a bit. Turbulent air makes it furl early sometimes too. All the rest of the ups and downs are due to varying wind speed, it is never smooth from that direction. I'll be modifying the furling arrangement so that it doesnt happen so early, max gusts I see at home are generally only 50-60km/hr. It furls before 40km/hr by design at the moment. I'll adjust it when I redo the blades and bearings before putting it up a higher tower. I do not live in a good position for wind power- average wind speed over recent months is 3-4km/hr! The WTGs are just there to generally collect SE winds on summer afternoons, and during extended cloudy periods when strong SE wind can blow. I have made blades from marine ply over the past 18 years (geared up and driving alterntors producing up to 1kW) and they have worked very well. Ply is laminated wood anyway. I've just laminated 2 or 3 sheets of ply to make it thick enough to take the aerofoil section, and shaped with a power planer. I certainly think ply is superior to extruded Al section, which is very prone to metal fatigue. Loomberah weather +solar&UV, astronomy, photography, organic farm |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Loomberah, The problem with Plywood is only half the timber is orientated in the right direction. Plywood was designed for strength in 2 dimensions, and a windmill blade requires most strength in only 1 dimension. If the blades are chunky then ply would do. My own carved blades taper to 30mm chord and 5mm thickness at the tips, so my blade timber requirements were not met by plywood. Gordon. become more energy aware |
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| Loomberah Regular Member Joined: 11/06/2008 Location: AustraliaPosts: 43 |
My blades are heaps chunkier that yours then, chord ~80mm and 15mm thick at the tip. I've never had the ply blades fail, which is more than can be said for the heavy double cast iron pully that I had some on in 1994. It was very well balanced, but winds that were possibly as high as 150km/hr were just too much. Lots of damage all around from that storm, but the 21m tower remained upright despite the bad things going on with the hub at the top. I found one blade near the base of the tower, one about 200m away, and have never found the 3rd one...maybe it went into orbit  Loomberah weather +solar&UV, astronomy, photography, organic farm |
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| kevindion Regular Member Joined: 28/07/2010 Location: ChinaPosts: 59 |
watch your mouth boy,do you know how much money this chinese worker could earn by making this so call "stuff"? less than 200$/per month ,it is cheaper then the "stuff",you could feel sorry for their workmanship,but never feel shame..... |
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| kevindion Regular Member Joined: 28/07/2010 Location: ChinaPosts: 59 |
so tell me,i want to buy a chinese windmil,which brand is the best?on another word,which brand is not bad? |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5124 |
Hi kevindion. We all know how hard the Chineese work. The average Chineese person works very hard for little pay. Sometimes the quality of products from China isn't as good as it could be, but thats not the fault of the worker. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glenn The Chinese products are good as far as engineering design is concerned its the quality control and worker training that lets them down. I know they work for very little in the way of wages, but that is their level of society there, and like most of the developing nations they go through this phase as did the Japanese in the early 50's of last century, they produced cheap junk and flooded the market with it, but now they produce some of the highest quality products in the world, so much so that they now have to outsource production to other nations on the developing list to be able to sell on the world market, as Japan sinks into a limbo due to lack of work at home. China is now well down this path, as I have observed their development over the last 30 years and they have gone from making junk to reasonable quality and going ahead like a train, the products we are seeing come in our field come from the fringe of this development and will improve dramatically over the next few years. Their advantage over Japan is that they don't have to outsource to other nations as they have their poor internally. They will take over the world in the supply of all sorts of innovation in the next couple of decades as they are now doing in PV panels and computer components. All the best Bob Foolin Around |
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| kevindion Regular Member Joined: 28/07/2010 Location: ChinaPosts: 59 |
non of you guys know something about chinese.even someone lived in china for a long time. i have been worked with foreigner in chinese countryside,and help many of them to improve their life,we aways said that we want to help this farmers,but the true is this farmers have done a better job then what we thought,they are the mr.helper.you have no idea how wonderful they are. i aways said that,chinese farmers could be anyone they shoul be.they could be the hardest worker when they work in factory,be a amazing creator when they have nothing in their farm,or to be the most loyal,brave and battlewise soldier in the world. i am learning from all of you.i want to make windpower for this farmers that still have no electrical power. The course in physics I have taken in the...highschool is good,i hope it can help me to understand what you guys talk about. i do not mean to anyone~ have a good time ~ |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 574 |
HI Kevin you quote i have been worked with foreigner in chinese countryside,and help many of them to improve their life,we aways said that we want to help this farmers,but the true is this farmers have done a better job then what we thought,they are the mr.helper.you have no idea how wonderful they are. i aways said that,chinese farmers could be anyone they shoul be.they could be the hardest worker when they work in factory,be a amazing creator when they have nothing in their farm,or to be the most loyal,brave and battlewise soldier in the world. This is true story 
All the best Kevin Dwyer |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Kevin The farmers are the salt of the earth there in China as in the rest of the world and they are good at things because, they must be to survive. If as you say you are there to help these farmers to have electricity in the rural areas, you have the raw material in your country, but it will take some skills to make it workable, I am sorry I can't recommend a specific make and model wind turbine as all the ones I have tried have had problems, but can be fixed with a bit of work, the most suspect units have plastic housings and structural parts, be wary of those as if they fail in service there is the risk of personal injury or death to any one it hits as it goes into free fall. The troublesome electronics can be thrown away and fitted with simple systems that are very reliable, the bearings are standard items and can be replaced with better quality ones for a small cost, the blades vary in quality over the range, they can be repaired and balanced properly by following the hints in this forum. You can make them work well as the design concept is sound. All the best Bob Foolin Around |
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