grid tie safety question

Discussion in 'Connecting to the Grid' started by chandler, Mar 21, 2012.

  1. Hey guys,

    I just purchased a 12oo watt power jack grid tie inveter off of ebay that i will be using with my solar panels ...I just wanted to see if anyone here has had any safety issues with their plug and play grid tie, I dont want to burn my house down!!! lol , my panels a re rated at 400 watts each and the open voltage falls within the parameters of the grid tie

    thanks!
     
  2. Minnesota

    Minnesota WindyNation Engineer

    The general answer is NO. They have fuse(s) on the DC side and on the AC side, so any excess current situations and they should protect themselves. I've not heard of any fires with these GTIs. That said, make sure you size your wires and connectors appropriately. Also be aware that the 1200w is a burst level, and you should run them with only about 600w worth of panels in my opinion. I've never heard of a 400w panel. Do you mean 4 x 100w? The largest I've seen is a Suntech 395w but it has an open circuit voltage of 99Vdc.
     
  3. i actually made a mistake , my panels are rated at 240watts each,(thanks for catching that) what size wires would you recommend, right now I have the grid tie connected with #6 wire
     
  4. Minnesota

    Minnesota WindyNation Engineer

    #6 is good for 55A and since your 240w panels will use ~7.7A each, you're good to go.
     
  5. ok good, thank you minnesota!
    now, I also bought a sun 500 watt grid tie for my turbine, i plugged it it yesterday for the first time and the red fault light came on , then the green light flickered for a while. There wasnt any wind, so eventually it shut down (no lights , not even fault light), this morning I unplugged it for about 12 hrs (no wind today either)and when i plugged it back in , there were no lights at all, is this nornal?
    I also tried to test it with my 12v battery bank and it still didnt turn on?
     
  6. Minnesota

    Minnesota WindyNation Engineer

    What is the voltage range for the GTI and what is the voltage of your Battery bank?
     
  7. input voltage for the gti is 10.8 to 30 v dc and my battery bank is at 12.9 v when i tested it with my voltage meter
     
  8. Minnesota

    Minnesota WindyNation Engineer

    The instructions say to connect the grid first, then the DC source. This is because any power coming in from the DC source needs a place to go (the load), and the grid is the load. Same goes the other way ... you must disconnect the DC source first. Failure to do so can fry the GTI.

    Sun-G GTI LED Status Conditions:
    If it is connected to the grid but the DC coming in is << 10.8V, then the RED and Green LEDs will be OFF. This is the normal nightime solar or no-wind condition.
    If it is connected to the grid but the DC coming in is > 10.8V and less than 30V, then the RED LED will be OFF and Green LEDs will be dance.
    If it is connected to the grid but the DC coming in is > 30V, then the RED and Green LEDs will be OFF. This is the normal overvoltage dump mode (SunG).
    If not connected to the grid but the DC coming in is < 10.8V, then the RED LED will be OFF and the Green LEDs will be OFF. There is not enough power to wake it up to light the RED LED.
    If not connected to the grid but the DC coming in is > 10.8V, then the RED LED will be ON and the Green LEDs will be OFF. This is the island protect mode.

    When the RED LED does not come on when it should and the unit apprears dead, that usually means one or both of the internal fuses have popped (generally the AC one).

    In your case with no wind but a good AC line, you might still be in the first listed condition above. Make sure you do have a properly sized dump load on the dump load terminals.
    See this Windy Nation article.
     
  9. Ok, so would the proper way to test the unit be to connect the positive and negative e from the battery to the GTI

    also, my 1200 power jack's green lights were flickering for a bit this morning,can it take longer than a few seconds to sync, input from the panels was 14amps
    thanks
     
  10. Minnesota

    Minnesota WindyNation Engineer

    If the voltage is close to the start-up threshold the green LEDs will "flicker."

    A solid test with a battery is to first make sure the GTI is connected to the grid. You can then attach the battery. The GTI should ramp up over a few seconds up to the maximum it can handle. Here is a video of a test I did like this:

     
  11. MN,
    Ive got my 1200 watt GTI working thanks! now I have a couple questions.
    my panels are rated at 240 watts each, i have them hooked up in parallel but im only getting about 260 watts during peak hours, but shouldnt I be getting about 480 watts into the WNAF? or should I connect the panels in series?

    also, I cant get the sun 500 GTI to fire up, I connected it to my battery bank, I have 6 6v batteries hooked up in parralel and series..where should i be running the lead and negative from, the middle batteries? i have 3 batteries on one side and 3 batteries next to those, like a rectangle

    thanks in advance!!
     
  12. Minnesota

    Minnesota WindyNation Engineer

    It is a bit of a mystery, but these GTIs only seem to work well with one well-matched GTI per panel (a 500w in your case). I've tried 2 identical panels of mine in parallel on one of my GTIs and the power only goes up perhaps 50% :mad:. I still don't know why that is. Also, some of these GTI are made up of perhaps 4 sets of 300w GTIs inside in parallel - something that also does not work well for scaling the power.

    To test your Sun500, just connect up 3 of the batteries in series, making 18V. The top battery (+) and the bottom battery (-) go to the GTI. Make sure you use fat cables to the GTI as you will be pulling perhaps 34 amps. You'll need #8 AWG or fatter.
     

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