Some grid-tie questions and in particular Sun-G Wind rated

Discussion in 'Connecting to the Grid' started by timber, Apr 28, 2012.

  1. timber

    timber WindyNation Engineer

    Hi guys,

    I'm new to any type of grid tie system but I've been reading up (posts here at WN) and am very interested in learning more so I can try to reap the most from (on average) very poor wind and solar conditions that we have here. (Getting above many neighboring tall fir trees is not an option so I live with turbulence, changing wind directions and less than stellar solar exposure).

    Over the last decade or so I've come to realize that (due to conditions noted above and restricted budget) AE is really just a fun hobby for me. (But this doesn't stop me from wanting to learn more and enjoy the hobby).

    Just some background:
    If you haven't seen it my current system is posted here to give you an idea of what my little system is about.
    I plan to add to the solar ... thinking about getting two 110 W Kaneka Hybrid PV Modules and bringing my old 2 phase motor conversion and a DC motor (that Murray gave me ... Thanks again Murray!) back on-line. Perhaps with all of the above I can see a few watts on a very windy, sunny day. :D

    Regarding Wind Rated Grid-Tie Inverters:
    1) In your opinion, are plug-in grid-tie inverters, such as the SunG, generally ok to use in the eyes of public utilities or building codes? (I can understand if you don't really want to answer this question but I'm trying to get a feel for where they might stand on these). IMO, they're safe to use as long as they are properly fused, wired correctly etc. and have a cut-out function (and relay to dump load) if the grid goes down.

    2) Are some SunG (Wind Rated) Inverters DC input and some AC input?
    I'm wanting to find one that has AC 3 phases and will help me get the best from the variable output from my WindTura 500. (But ... it's confusing the way these are advertised, see #3 below).
    Think I found the answer ... they have both types.
    ** Larry, are the Sun-G wind rated inverters that you've been using the Model SG-500 (and did you have to specify if you wanted 3-phase or DC type)? It's all so confusing since there seem to be many different configurations, versions etc. Like now I'm seeing 600 Watt instead of 500 Watt on some.
    I've got an email into Ronnie Freeman to see what he's got (maybe he can clarify).

    3) I did some searches for the SunG and, of course, found some on ebay or amazon but it sure is difficult to find consistent or detailed information or specs on them. One ad I was looking at showed two different pictures of the input for the same inverter, one pic had three connections (what I would expect, one for each of 3 phases AC from PMA) and the other pic had only two connections (positive and negative). :confused:

    4) If I do get one of the SunG's I'll likely get a 250-300 Watt but would consider getting a 500 or 600 Watt if there are some advantages other than just accommodating the greater input. Do the lower watt inverters draw less current from the system or are they relatively the same in this regard?

    5) Any recommendations on particular sellers of SunG inverters?

    Thanks for any information that you can provide regarding the SunG
  2. Minnesota

    Minnesota WindyNation Engineer

    I think these GTIs are safe. They recognize that the grid is down and they stop inverting, so no lineman is at risk of getting shocked. That is the main concern of the utilities. `If you plan to net-meter, most USA utilities require an outside shut-off switch from the GTI to the panel or service line, and that the GTI be UL listed (which these GTIs aren't currently). It is not that expensive to get UL approval so I do expect it will happen. The quality of these have been improving over the last few years as I've repaired a bunch of them. One utility in Florida has approved a guy's wind and solar net-metered system that used these GTIs. The system passed the anti-islanding test and he had the shut off switch installed properly. I've not heard of one case of a utility fining a person or shutting off their service for using these GTIs even though they do have the right to.

    As for how each GTI model behaves with various turbines, that is less clear. The wind MPPT function is programmed-in and is subject to change. The SunG-wind GTIs clearly prefer turbines that never generate high volts, common with car PMAs. Some car PMAs generate over 300 volts! That said, turbines that can operate up to 60V in winds under 32 MPH are a good fit as a 800w turbine at 60V only draws 13 amps so the line and stator losses will be reduced. The Windtura 750 and the HY1000-24 seem to work well with the 22-60V Sun wind GTI, but there frankly is not a lot of data to go on.
    TomT likes this.
  3. timber

    timber WindyNation Engineer

    Thanks Minnesota!
    We can hope (for the sake of AE advancement) that the makers of these units do get a UL listing sometime in the near future.
    I suppose if the units sell like hotcakes without a UL listing there may not be as great an incentive for them to get the listing soon but, in the long run, I would think it would improve their bottom line.

    With my wind conditions I don't think I'll ever see voltages higher than 30V so it sounds to me like there is a chance I could see some benefit from SunG-wind GTI.
    I'm still not clear on whether they make a 250 or 300 Watt (Wind) GTI but if they do I think that's the one I want to get.
    I'll do some research on that, but as you already know, it's really difficult to know exactly what you are getting in regard to software.
    Hopefully Larry will be able to let us know what he's found in the way of (250-300) Lower Watt Wind GTIs (if any).

    Your video on opening up the Sun-G and Power-Jack inverters was interesting and most helpful ... thanks!
  4. TomT

    TomT WindyNation Engineer

    Check Ebay for the 300 watt wind GTI. They are not always there Forsale. So keep looking or setup an email alert so anytime new items show up you will be notified.
  5. leamywind1

    leamywind1 WindyNation Engineer

    Real quick as some of the these answers can be found in my post's. The smaller Sun G 250 or 300 (WDL) can not hold my HY 400 all the way down to get 300w of a rated 300w Sun G for exsample. That pma goes right through it meaning it hits over volt to fast before getting the rated 300 watts or even 200w. When you are using PMA outside of the Windy or Wind Max right now we have no confirm data until others do exstensive testing and report their findings. Since the steepness of these inverters can not be adjusted as far as we know, it is a guessing game for each different PMA. However a few of us have laid the groud work out for a windy nation or a wind max. After the ground work, the site inclluding obstructions and height will dictate the ultimate performance and of course more testing. Just chaining blades from 3 to 5 because a site does not have enough wind can change performance. So between the PMA, the site and the blades all have to be well know to achive the even close to rated power performance. Right now using anything but a WN or WM wouldl be an experiment from the very start however we would love to follow it.:)
    TomT likes this.
  6. timber

    timber WindyNation Engineer

    Ok, thanks Tom and Larry.

    The ebay deals do seem to have the best prices and I see many have free shipping as well. :D

    You've given me a few things to think about (I'll keep reading your posts on the Sun-Gs Larry). I think the Sun-500G-WDL is what will likely make the most of my Windtura 500, initially. It may be worth adding a 250-300 Watt grid tie later to catch the lower end and tie the two as you have shown us how to do. (The thread discussing this is very helpful in understanding how you've managed Low, Medium and High winds using the Sun-G inverters ... great stuff).

    I'm in the process now of trying a few other options before going with any grid-tie.
    I had 3-blade 35" Windgrabbers on the Windtura 500 but just swapped them with a 5 blade set @ 60" diameter to see if this will help any.
    Today I put together a synchronous belt and gears to increase the RPMs of the Windtura @ 1:3.2 ratio.
    Here's a pic of the Synchronous Belt Setup on an Electric Bike I made a few years back in case anyone is interested.

    Could be a waste of time but I had the parts laying around not being used, so why not give it a try.
    Once I get the Windtura dialed in to local conditions the Sun-G should be able to help make the most of any output via the MPPT feature.

    My current DC panel will go into the travel trailer to manage and keep up the batteries there where I'll have solar on the roof and a tilt-up pole setup for one of my smaller turbines.
    That's the plan ... thanks to all for your input.
    TomT likes this.
  7. timber

    timber WindyNation Engineer

    Regarding the voltage ranges of the Sun-Gs:
    1) When using a 22-60V GTI what happens when the PMAs voltage is under that ... does it still go into the grid?
  8. TomT

    TomT WindyNation Engineer

    GTI does not put anything into the Grid till the turbine or Solar panel reaches 22 volts on a 22-60 volt GTI.
    And that varies depending on how fast the voltage is rising.
  9. timber

    timber WindyNation Engineer

    Thanks Tom,

    I see now, this is why a lower voltage inverter used in parallel with a higher voltage inverter (which has dump load) can be beneficial.
    I need to find ways to harvest the lower wind speeds, turbulence and changing wind direction here but not miss out on the higher winds when they do show up ... this helps.
    I can understand and fine tune the mechanical end of a system by using various techniques but I'm also am learning that efficiency, using grid tie with MPPT, is likely to also be an essential component in making the best of any power produced.

    My current thought is to use a 250-300 Watt Wind Rated GTI to reap the low end with a parallel 500-600 Watt WDL to take on the higher end.
    I think my budget will allow this, especially since I'm taking storage out of the equation.

    Thanks for your input!
  10. Timber, I recently added a 300 watt wind rated Sun G 10.8-30v. in parallel to my Outback 2524. This setup is working out great! I am seeing watts produced everyday. When the winds are lower my Sun G takes the amps up to 250 watts, after that the Outback shares the amps. This setup allows my Sun G to hold at 240-250 watts and any extra passes smoothly through My Outback. I have never seen the Sun G over volt in this setup. Leamy came up with this Idea for me, much appreciated help.
    TomT likes this.
  11. timber

    timber WindyNation Engineer

    Good deal Dean-o,
    Glad to hear your system is working great using multiple stages of wind power.
    Yes, without the previous research and investments of a number of members here I'd never get close to understanding how best to use these GTIs.

    It's still only a dream but it sure would be great to see relatively inexpensive MPPT Grid Tie Inverters UL/ FCC approved and basic standards be developed so many people, not just the elite few (who can afford meeting current requirements/ costs) could migrate toward AE.

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