Installed grid-tie inverter today





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  1. #1
    Join Date
    Sep 2006
    Location
    Bloemfontein
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    43
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    Default Installed grid-tie inverter today

    Since I am busy developing a solar tracker controller that runs on a grid tie inverter, I installed a grid tie inverter for myself to help improve the algorithm for the large systems.

    I bought a Solis 4G inverter, which IMHO is not only well priced, but excellent quality.

    The system will not feed back into the grid, as it has a CT that monitors the condition.


    What makes a grid tie system attractive, is that it can actually pay for itself in a reasonable time, provided it is deliberately under sized so that one does not spend money on generating capacity that is not used most of the time.

    However, this is NOT a system that can provide any kind of backup during load shedding and many people does not understand that when installing a grid-tied system.

    I am quite excited to see how it will work.

    And it is nice to see the tracker move during the day.


    I named my Controller "Ahmose", which was a high priest of the sun worshipers.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  2. #2
    Join Date
    May 2009
    Location
    Hillcrest, Malaysia
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    63
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    18,583

    Default Re: Installed grid-tie inverter today

    Just be careful of the statement "not feed back into the grid".

    CT based control is a bit like Traction Control. It cant intervene until "YOU ARE FEEDING BACK INTO THE GRID". There has to be a (small) error to close the control loop, just like all closed loop control systems. (Think about your solar tracker, there has to be an error to respond to.)

    Once you start feeding back the CT detects this and the Inverter backs off. Once the Inverter backs off there is no control, so the Inverter lands up sitting in a no mans land of a small current feeding back which keeps the control loop happy.

    This is not normally a problem, except that some smart consumption meters see this small reverse current as tampering and shut down the supply.
    Cheers

    ZS5KAD
    3 V8's
    NA TwinTurbo SuperCharger
    A V6 and an inline 4

    The frogs are starting to notice that the water is getting warm but it is already too hot to do anything about it.....

  3. #3
    Join Date
    Sep 2006
    Location
    Bloemfontein
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    Default Re: Installed grid-tie inverter today

    Quote Originally Posted by Fluffy View Post
    This is not normally a problem, except that some smart consumption meters see this small reverse current as tampering and shut down the supply.

    Mine fortunately does not do shut down. I did check the specs.

    However, I am paying for the small current going back into the grid as mine counts it both ways.


    My next project is to build a small geyser controller with a solid state relay that can ensure that I always draw say 0.1A minimum from the grid, so that one can use the water as a "battery".

    For many house holds that does not have a solar geyser, that can be a great bang-for-buck device in combination of a grid-tie inverter.

    And you will be able to use that on a standard geyser.
    Last edited by biltong; 2019/11/14 at 06:53 PM.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  4. #4
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    43
    Posts
    3,200

    Default Re: Installed grid-tie inverter today

    I got the solar tracker controller working in Alpha version this weekend.

    It was great fun. By now, most functions are working, like waking up in the morning and going home in the evening.

    My system has battery backup too, so that I can drive the servos for wind protection if all the power is down.

    For now, still working on a solar sensor, as the algorithm is easy to get going.

    For now, still on solar sensors, but working hard to get my preferred method going on which I will report later.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  5. #5
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    63
    Posts
    746

    Default Re: Installed grid-tie inverter today

    Very interesting. As the Solis works great and being offered at a good price it is a worthwhile piece of equipment. Very happy with mine.

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