 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Windmills : 12V 900W Turbine - Splitting the Load Over 2 Controllers?
  Page 2 of 2 |
|||||
| Author | Message | ||||
Technophiliac Regular Member  Joined: 18/12/2020 Location: New ZealandPosts: 89 |
Would you please advise the brands and model numbers or give url's? Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
||||
| Kamak Senior Member  Joined: 13/04/2021 Location: CanadaPosts: 150 |
Is there not a full-wave rectifier between the 3-phase output and the MPPTs? Or do MPPTs do the rectification within, right from the turbine? Sorry I did not know this. I thought it could be _________________________________________- (500W DC/DC current limiter) - 500W MPPT 900W Turbine AC out - Rectification/Smoothing Filter _________________________________________- (500W DC/DC current limiter) - 500W MPPT Edited 2021-04-19 02:09 by Kamak |
||||
| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 89 |
Is this correct: "Cheap 400W turbine" as seen at https://www.thebackshed.com/forum/ViewTopic.php?TID=12970 Seems you indicate its a 12V turbine. Xantrex C40 - "I'm considering purchasing the Xantrex C40 (40amp) model as it is 12/24/48v compatible, for use as a diversion controller Xantrex C series" https://www.thebackshed.com/forum/ViewTopic.php?TID=13143 40 amps @ 12V is 480W, not the claimed 1000W (Although used at 24 and 48V it would be) Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
||||
| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 89 |
Yea nah. The 3 phase SSR's I found start at 24 volts and upwards. Not likely to work on a 12V generator. Plenty of low voltage DC SSR's around though, looks like it'll be option 2 with 3 phase rectifier and switching a DC load(s) in and out as needed. Hope the generator makes sufficient power to merit the exercise! Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
||||
| Solar Mike Guru  Joined: 08/02/2015 Location: New ZealandPosts: 1122 |
If you 3ph rectify the AC, then a dump load diverter like the one in this post PV Diversion could be modified to run at a lower voltage and allow dumping of 8 loads as the voltage increased above a set point. The mosfets used in it are 5A rated with the high voltage, however high current lower voltage devices would also work here. I'm still waiting for the pcb's to come back; so haven't tested the design yet. Cheers Mike |
||||
| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 89 |
Clever Mike. Another even simpler approach has occurred to me. I can add one of these in and they will soak up 300W or so (at 12V - when volts reach 14.5V) if needed and otherwise let my main MPPT 12V 500W controller work. It might need DC from the battery, possibly with an inline resister to minimise the back flow current yet make it run still.  There is a youtube tear down of a similar one (I recall) showing some of the clever circuitry in this type of device. For example the AC to DC bridge uses 3 diodes and 3 active devices. (MOSFETs?) Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
||||
| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 89 |
Maybe author is right - and I waste a lot of time and resource on this. Hmmm. I better test. Using a Hitachi 620W drill on low speed (1100rpm no load) it ran up to 444 rpm (measured by controller). Had to hold drill with both hands! Max current generated was 22.21 Amps. Max Watts were 338W. (= 15.21V) But actual voltage climbed to over 16 Volts using reasonably charged SLA 12V batteries in parallel summed to 144 Ahr. (Current and watts measured using Jaycar 200A Digital meter.) Something smelled. Realised it was the drill smelling! Part of drill body found very hot. Drill rpm maxed at 444 but quickly dropped to 415 rpm. Ran 3 bursts with the drill total of 2.27 mins with cooling down time on between. Turbine is rated at 650 rpm which I could not achieve and was miles away from. 338W at 440rpm, bearing in mind typical power curve, what will it be at 650 rpm? My expectations the turbine is a true 800W turbine remain to proved - and particularly disproved. To my mind this test does not disprove the turbine is a true 800W unit and supports it probably is. The extent the circuitry behind it plainly needs to cope with 800W - and more. Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
||||
| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 378 |
I don't know what your power consumption is, but this is my experience with PV panels. I have 5kw of panels. What happens is I never see that sort of output from the panels. By the time the sun gets up high enough to provide full power the batteries have already charged enough that my regulators are already backing off the output of the panels. I have three banks of panels ( all different ages and sizes) connected to three MPPT controllers. The outputs of the controllers are paralleled not the inputs. So by the time the sun is way up the batteries are already being regulated. I am guessing that with your wind turbine the same thing would happen. By the time the wind gets strong enough to actually output full power from the turbine the regulators will be dumping power. Unless of course you are using so much power that the battery voltage drops low enough to allow full power. I find that the internal resistance of my VRLA 660 amp hour 24 volt bank don't allow much more than 2kw input anyway. Have fun experimenting. Pete |
||||
| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
I think the Max output of the alternator is somewhat irrelevant. That are the blade going to be able to drive it to in typical winds you get in your area would be more the question on my mind. Seems with the efficiency you got from the drill test the thing may be as little as 50% efficient. If that's the case, seems like a lot of blade and a lot of wind is going to be needed to crank it to full output. Other question would be how sustainable is full output. What it can do and what it can hold are likely to be entirely different things. Yes, You would still want your output components to be able to handle that IF the wind and blade will ever be able to generate it. Maybe you could set the thing up with an induction motor and just control the speed with a simple PWM to get it to rated speed and then see what it is doing. Still think the blades and wind are the important things. Must be calculators somewhere to work that out. |
||||
| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
That's a very interesting observation Pete. Not having a true battery setup it had never occurred to me but it does gel with other things I have read about. One thing I have heard of for PV over Tube water heating is the same. In summer the water tank can be up to speed at 10 in the morning and the rest of the day thing thing sits there boiling off or doing nothing. With PV it may be less efficient but at least what you do get can be put to use elsewhere. Only so much HW one needs but power can be used all day. I suppose the upside of your setup follows my position with solar in Overclocking inverters. It's not the bright, long summer days you have to allow for, it's the short winter and crappy days. I find my grid tied inverters can put out as little as 10% in bad weather as they do, sometimes Literally as they did the day before.... whatever time of the year that is. It's a Huge fall of and the extreme end of the scale but even winter low months can be a 3rd or less of the summer months. I was up early this morning and saw my slightly North east array was already making 2.5 Kw at 7 am this morning. Not sure now what size the array is atm, 4Kw I think But that's good power early on to build for the total for the day that's for sure. Might set up the Direct PV to hot water system up again. The weeds are going nuts with the rain and boiling water ( I bypass the Thermo) is the best and cheapest weed killer I know of. Do you find your batteries are still up around the same time in winter as summer? |
||||
| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 378 |
Hi Dave, I have deliberately over sized my system, because we live in an Alpine area where we get a lot of foggy days and rain. There have been a couple of days where the batteries have hardly got any charge all day but the next day they have filled up. So far since I added an extra 3kw of panels we have not had to run a generator and battery charger at all. That is a boon , I prefer not to use petrol or have the noise. We got through winter with just solar power. Even on cloudy days ( unless they are thick dark clouds and fog) our system charges up to 100% each day. On clear days at the moment we are fully replenished by around 10am, then I use the extra capacity to run the electric woodsplitter, shed tools or water pumping. We tend to use around 10% to 12% capacity overnight. That is running the fridge, charging laptops, lights and TV. I do not let the batteries go below 70% charge. So yep all good in Tasmania. Cheers Pete |
||||
pollenface Regular Member Joined: 01/09/2020 Location: AustraliaPosts: 41 |
Here you go https://tinyurl.com/37j8u46t Off grid man caver |
||||
| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 89 |
Thanks for your suggestion of "Wind Turbine Charge Controller Waterproof 40A Voltage Boost Low Speed Regulator" - 12/24V. 12V @40A = 480W. Not going to cut it. Maybe two PWM in parallel might work? Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
||||
| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 89 |
Interesting, thanks. Out of interest can you share are the panels all in the same plane? Fixed? Angle? And your latitude? (Tasmania approximates....) Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
||||
| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 89 |
Efficiency? Hmmm Apparently the power is the cube of the wind velocity. Ref (https://windexchange.energy.gov/small-wind-guidebook.pdf The manufacturers graph suggests I'll get 340W in ~6.5 m/s wind. If that is correct, for my location I do not see efficiency as a priority issue, given we get winds that at times average 10 m/s / gusting 20 m/s - Do I need to worry about efficiency? I consider I need to be more concerned about managing the power and turbine! If I'd realised at the time of ordering the 12 V turbine the controller was going to be an issue I might have been better to have gone with 24 V. Benefit of hind sight! I've got the 12V version, will go with that if I can as I've been running a 12V bank / test system. Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
||||
| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 378 |
Hi Davo. Our place is at 41.38 degrees South. I have three kilowatts of panels on a ground mount ( heavy timber) that face North. They are at 35 degrees as any steeper would not work for late autumn and early spring. The winter sun is only very low for a short time so I compromised on what would work best here. I have two kilowatts of panels on my shed, they face West North West. ( the way the roof does). The roof is at 22.5 degrees and that is the panel angle. I did not want to raise them on stands for aesthetic reasons and also because we get a lot of strong winds and the roof stands I have seen are far too light. The North facing panels do most of the heavy lifting but on cloudy and foggy days ( we get a lot) the WNW panels do a great job. Cheers and good luck with the wind generator Pete |
||||
| Page 2 of 2 |
|||||
 Print this page |
