Johann1982 Posted December 1, 2016 Share Posted December 1, 2016 Any suggestion for a Wind turbine? He has a 48v bank... Quote Link to comment Share on other sites More sharing options...
Guest Posted December 1, 2016 Share Posted December 1, 2016 5 minutes ago, Johann1982 said: Any suggestion for a Wind turbine? He has a 48v bank... Nope, but @Mike can help. Quote Link to comment Share on other sites More sharing options...
Guest Posted December 1, 2016 Share Posted December 1, 2016 And @Energy may also be able to help. Quote Link to comment Share on other sites More sharing options...
Mike Posted December 1, 2016 Share Posted December 1, 2016 2 minutes ago, The Terrible Triplett said: Nope, but @Mike can help. whats needed? Quote Link to comment Share on other sites More sharing options...
Johann1982 Posted December 1, 2016 Share Posted December 1, 2016 Hi Mike. My friend on a farm has this setup: 1x 5kva Axpert 12x 100ah 12v Stride batts 3x 260W Panels During summer he's ok, but his batteries are taking strain in the winter. He just needs something to carry the load at night and cloudy days. I was thinking he can use a wind turbine up on the hill above his house.. What can you recommend? Quote Link to comment Share on other sites More sharing options...
Mike Posted December 1, 2016 Share Posted December 1, 2016 his batteries are prolly shot already. i run a 2kw mainly for winter as well. kept my batteries at 80% most of the time. he should consider the right size battery bank with a decent ah rating and add a 1 or 2kw turbine to assist.. in my view. i wll send you a pm Quote Link to comment Share on other sites More sharing options...
Johann1982 Posted December 1, 2016 Share Posted December 1, 2016 He draws 300w max during the evening till around 10pm. Then it drops down to 50w. I think his washing machine draws the most at around 700w, but that is only during daytime when sunny. Quote Link to comment Share on other sites More sharing options...
Johann1982 Posted December 1, 2016 Share Posted December 1, 2016 Has any tried running 2x 24v wind turbines in series to charge a 48v bank? Quote Link to comment Share on other sites More sharing options...
Johann1982 Posted December 1, 2016 Share Posted December 1, 2016 or even 4x 12v turbines? Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 1, 2016 Share Posted December 1, 2016 17 hours ago, Johann1982 said: Hi Guys, one of my friends live out on a farm where he is totally off-grid. He currently has 1x 5kva axpert, 12x 100ah Lead Acid batteries and 3x 260W Panels. He is fine during the summer, but winter is a problem. He obviously needs more batteries, but his bank is over a year old already and shouldn't add to it. There is a small hill just above his house where the wind blows constantly. Would a wind turbine be more effective in the long run or should he rather add another 3x panels and replace his bank with 16x 100ah 12v Gel Batteries? Or should he risk adding another 4x batteries to his old bank? I was initially sceptical of the usefulness of a wind turbine in inland areas in a off grid situation as we generally do not have enough wind to see a marked difference in energy production. I always maintained that money was better spent on more panels and batteries. Recently I have changed my viewpoint. We here in the Karoo get wind in the evenings which is a difficult time in an off grid situation. The sun has set and yet now you have increased baseload with lights and maybe television and occasional cup of coffee. Thus a turbine would offset this usage and so a wind turbine helps with a difficult time of day, complements solar and can compensate for too small a battery bank. Recently I have been looking at DIY vertical axis wind turbines (VAWT). Essentially you wind coils and embed them in fibreglass as a stator and the rotor has neodymium magnets. As the stator can be fixed there is no need for commutators etc. There is no need for a vane as they can operate with wind from any direction. The VAWT is less efficient that a horizontal axis wind turbine (HAWT) but are better in gusting wind and around buildings where the airflow is less laminar. Around my homestead with trees and buildings a VAWT is the way to go. Edit: substituted laminar for directional Mark 1 Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted December 2, 2016 Author Share Posted December 2, 2016 I built a VAWT out of half oil drums some years ago when I was playing around with DIY wind. It worked in the sense that it is easy to build, but because it is slow speed it is difficult get get enough speed at your alternator to generate any appreciable amount of power. I was using 12V at that stage which was acheived when the wind was blowing quite strongly, and then the voltage drop on the cable would make the power supply negligable. 48V was rarely seen.On the plus side they are very robust and the VAWT still turns even though I have removed the alternator. I was using a Windbluepower permanent magnet alternator. The pics below show what it looked like. I am going to be putting up a wind turbine soon, for precisely the reasons that Chris mentioned. I think it will augment the solar production on cloudy weather days, which are usually windy, and help a bit at night as well. viper_za 1 Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 2, 2016 Share Posted December 2, 2016 Savonius VAWTs (oil drum like cups) are very inefficient and it is not surprising that you did not really achieve high voltages. There are several tricks I think (I have not completely researched this so there probably big gaps in my understanding (sort of like the ou with just a few teeth that smiles for Obie Oberholzer's photos in Namaqualand -pearl one miss one). Rotor needs to be either an Archimedes screw (very difficult to build in a DIY situation),a Darrieus (egg beater like) or a T rotor with aerofoils. Build your own rotor and stator a vehicle alternator is designed around high speed. build a 3 phase stator with coils in series to raise the voltage and have high number of turns with a thicker gauge wire to increase voltage and lower resistance. use neodymium magnets for maximum power. sandwich the stator between two rotors both containing magnets (not that easy but possible. There are some trapezoid 56kg pull neodymium magnets sold by a UK based company for R700 a magnet and you need twelve to complete the set so just over R8000 before you have wound a coil. I think we will skip on those. Quote Link to comment Share on other sites More sharing options...
Mark Posted December 2, 2016 Share Posted December 2, 2016 @ChrisHobson see attached for a plan I have been reading for a while... Pico turbine plan10B.pdf Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted December 3, 2016 Author Share Posted December 3, 2016 12 hours ago, Chris Hobson said: Savonius VAWTs (oil drum like cups) are very inefficient and it is not surprising that you did not really achieve high voltages. There are several tricks I think (I have not completely researched this so there probably big gaps in my understanding (sort of like the ou with just a few teeth that smiles for Obie Oberholzer's photos in Namaqualand -pearl one miss one). Rotor needs to be either an Archimedes screw (very difficult to build in a DIY situation),a Darrieus (egg beater like) or a T rotor with aerofoils. Build your own rotor and stator a vehicle alternator is designed around high speed. build a 3 phase stator with coils in series to raise the voltage and have high number of turns with a thicker gauge wire to increase voltage and lower resistance. use neodymium magnets for maximum power. sandwich the stator between two rotors both containing magnets (not that easy but possible. There are some trapezoid 56kg pull neodymium magnets sold by a UK based company for R700 a magnet and you need twelve to complete the set so just over R8000 before you have wound a coil. I think we will skip on those. At that price you may as well just buy a HAWT off the shelf, and skip the DIY part unless you have time on your hands. That alternator is not a vehicle alternator, it was a 3 phase permanent magnet alternator, so if it was really spinning you could get 100V out of it, and the turbine did do that on occasion. http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Low_Wind_p/dc-540.htm The specs show you should get over 12V at about 250rpm, and the way I has it geared that would be about 30rpm on the rotor. What I realised from the experiment (and I played with DIY horizontal axis generators as well) is that you need quite a lot of power in the wind to generate any electricity at all. If you stand in the wind and you can feel it pushing you, then you have a chance of making power. Breezes rustling the trees and grass will not make anything. Give it a try though, lets see if you can get it right. Quote Link to comment Share on other sites More sharing options...
Johann1982 Posted December 3, 2016 Share Posted December 3, 2016 I was thinking of building something like the attached photo. We normally get wind from the west or east so I was thinking of putting it on the roof apex where both sides of the roof would funnel the wind over the turbine making it spin. I would just add 3 more helix airfoils around the outside of the solid one in middle. Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted December 3, 2016 Author Share Posted December 3, 2016 I saw a really smart idea once, but have not been able to find it on the internet again. Basically it is a lot of small turbines that have gears on the outside, about 20cm diameter, so really easy to make from plastic. They are then arranged in a row with the gears interlocking (every second turbine is 'upside down') on a frame and the last one drives a small generator. You then have multiple rows each with its own little generator. Seems really simple.... Found it again : http://inhabitat.com/micro-wind-turbines-small-size-big-impact/ Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 3, 2016 Share Posted December 3, 2016 7 minutes ago, DeepBass9 said: At that price you may as well just buy a HAWT off the shelf, and skip the DIY part unless you have time on your hands. That alternator I was using was a 3 phase permanent magnet alternator, so if it was really spinning you could get 100V out of it, and the turbine did do that on occasion. I have found some suitable magnets (N50) for about R50 each. 11 minutes ago, DeepBass9 said: What I realised from the experiment (and I played with DIY horizontal axis generators as well) is that you need quite a lot of power in the wind to generate any electricity at all. If you stand in the wind and you can feel it pushing you, then you have a chance of making power. Breezes rustling the trees and grass will not make anything. If your turbine does not turn easily in the wind then there is a mismatch between the turbine and the rotor. Too big a rotor and the wind turbine spins easily in a light wind and is dangerous in a strong wind. Too small a rotor and turbine turns with difficulty. Exactly the same happens to windmills. If your cylinder is too big the mill battles to turn. The theoretical available power from a turbine is P = ½ (rho).A.V3 where P = power (Watts) rho = density of air (1.225 kg/m3) A = area of rotor (m2) perpendicular to the wind. V = velocity of wind (m/s). You've got to love the metric system. I cannot begin to visualise this formula in imperial units. The two important things to remember is there is the cubing on wind speed so it quite quickly ramps up, and in the oil drum rotor you only have ½ the surface area facing the wind. Horizontal Axis Wind Turbine (HAWT) achieve a maximum of about a 30% efficiency and a Vertical Axis (VAWT) between 15% and 20% depending on rotors. For a VAWT to produce 500W in fresh breeze it needs a Savonius rotor of about 8m2. Winnie Mandela's hat would pale into insignificance. Mark 1 Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted December 3, 2016 Author Share Posted December 3, 2016 Quote If your turbine does not turn easily in the wind then there is a mismatch between the turbine and the rotor. Try it, you will find it is actually a mismatch between your expectations and reality! Wind pump and wind generator are quite different. A wind generator needs speed, and the slightest load will kill that speed in a light wind. Chris Hobson 1 Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 3, 2016 Share Posted December 3, 2016 37 minutes ago, DeepBass9 said: Try it, you will find it is actually a mismatch between your expectations and reality! . OK I have tried to read as much as possible but nothing beats practical experience. Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 3, 2016 Share Posted December 3, 2016 14 hours ago, Mark said: @ChrisHobson see attached for a plan I have been reading for a while... Pico turbine plan10B.pdf Hmmm looks a bit small . The principles and star-delta wiring is good though. Quote Link to comment Share on other sites More sharing options...
Mark Posted December 3, 2016 Share Posted December 3, 2016 Up size boerseun. ..Sent from my SM-P605 using Tapatalk Chris Hobson 1 Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted December 3, 2016 Author Share Posted December 3, 2016 I will have a turbine running soon courtesy of Johann1982, its been quite windy over the last few weeks, I'm sure as soon as the turbine is up I will become becalmed.... Mark and Chris Hobson 2 Quote Link to comment Share on other sites More sharing options...
Mark Posted December 4, 2016 Share Posted December 4, 2016 On 12/3/2016 at 9:58 AM, Chris Hobson said: Hmmm looks a bit small . The principles and star-delta wiring is good though. Chris... looks like a good doc. With tested turbines.. Hugh Piggott Axial-flow PMG wind turbine May 2003.pdf Chris Hobson and DeepBass9 2 Quote Link to comment Share on other sites More sharing options...
Rob Moffett Posted February 1 Share Posted February 1 Hello from Windhoek! Great thread! Ya, no one has solar panels in their logos whereas the classic windmill is part of the vernacular of the Karoo / Platteland / Namibia landscape, a windmill silhouette graces many logos Neither are the three bladed aerodynamic electric wind turbines as aesthetic as the original Southern Cross or Climax type of windmill. Neither have I encountered dead birds at the base of a windpomp. Efforts to reduce bird strike continue. I've recently arrived at the same idea as the OP - to convert a classic windmill into an electricity generator is certainly a novel approach to re-purpose the many hundreds of windmills that are now abandoned. If the mechanical and electrical engineering maestros can be persuaded to apply their skills to the project would be great. Further, to top up the energy generation is it feasible to replace the blades with double-sided solar panels, that there is regular day-time energy production, and any wind generation is a bonus? Best, Rob Quote Link to comment Share on other sites More sharing options...
vrystaat Posted February 2 Share Posted February 2 Hiya Rob How is windy corner treating you? Your question on replacing blades on a windmill with solar panels, how would you transfer the power from the panels to the system? Also depending on wind direction your panels may not be facing the desired direction for best production of energy. Chances of the panels surviving in such a setup ?? Cheers Sean Ficksburg Quote Link to comment Share on other sites More sharing options...
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