Hooking grid ties in parallel?

Discussion in 'Connecting to the Grid' started by bluejay, Jan 29, 2011.

  1. bluejay

    bluejay WindyNation Engineer

    Does it matter if the positive and the negative are connected on the first in the group or is it more efficient to hook the positive power on one and the negative on the end one in the chain? Does it matter? I know one will hog the energy until to much and the other are needed. Just was curious if it will overload the first one if alot of amps are coming in with all incoming power connect to its terminals :?:
  2. bluejay

    bluejay WindyNation Engineer

    Sorry Murray, I know you are trying to get some organization to the forum and this prolly should of been put in the grid tie forum...A mod should move it there if possible,most forums have people to do the mundane tasks and keep order. ;)
  3. Minnesota

    Minnesota WindyNation Engineer

    I did a bunch of GTI tests on my YouTube channels and the results are interesting.

    First off, you can't connect them in series like a battery, so forget that idea.

    Second, if you connect 2 or more in parallel then one will dominate. I've mated 2 Power Jack 300s, and then 2 SUN 250s, and then a mix of the 2 types. They don't like sharing a source but you will get slighly higher overall output with 2 or more in parallel.

    My tests were with a solar source of 17v and 120-140w. My next set of tests will be with 17v and >250w. In this case I expect one will max out and the other will pick up the slack.

    The MPPT function does not allow pairing or sharing to be balanced ... one will take over, though it can take a minute or more for them to sort that out. Here is a good video of my test:

    Hope this helps.
  4. bluejay

    bluejay WindyNation Engineer

    I appreciate the response M but you didnt even remotely answer my ?....I know they arent to be put into series..
    In parallel I have ran 5 of of the 300w powerjacks{for solar}(suck) but had the neg on the top invereter and the positive on the bottom one..

    I was curious if the electric behaves different if say the pos and neg were hooked up to the power on the first one and the rest were chained to it...Seems like hooking opposite inverters would be a smoother flow of power for distribution then put all of it into one(alot of amps)..
  5. murray2paddles

    murray2paddles WindyNation Engineer

    Hey Blue,
    I think it is a heck of a good question regardless of where it is posted.
    I do not have any experience on the solar testing with them but Larry and I have been working together. He is doing the testing on multi turbines and mixing different amounts and watt sizes on the front end and the back end. I am supposed to stay with the single turbine testing and mixing my inverter set ups to compare also.
    Whoops, better go back a bit, when I say front end, I mean using the Sun 10.8-30 & back end the Sun 30-55.
    In this mix I am also using a Power Jack 1200 28-55 V. and a set of 4 SWEA 250's. for 1000 watt

    We have just recently placed an order from China for a few more inverters each to round off all the different options we are hoping to try. Unfortunately we have to wait for their holiday to be over until the shipping dept will send ( Chinese New Year ). This is teaching Larry how to have patience :lol:

    Unfortunately both our winds have been very low lately and have really slowed down our testing. when Larry comes back from the weekend maybe he can update everyone a bit on how up to 4 turbines are working together.
    I should be able to share some info from what I have seen so far running in parallel & supporting different volt ranges.
    One Turbine , Windy 500 feeding a Sun 500 10.8-30 on the front and a Power Jack 1200 28-55 for the back end. So far this has been the smoothest pair working together that are not of the same make. The Sun would carry the volts up to the high end of 400 watts and then as the closeness of the Volts mixed and one was closing down the other continued with little problems. The Power Jack then took over on the high volts. Both inverters were wired directly from the DC side of the rectifier.
    The Power Jack also had a dump load supporting it. The danger was that the Sun did not have a dump set up and I relied only on it's volt overload to shut it down.
    In the low V / winds you could se that the Sun's MPPT was in charge and clamping the turbine to lower Volts. When the Volts dropped the Sun would take over control of clamping down the turbine once again .

    Next test for me was moving from the shop to the house and losing my patience on just testing one turbine only :roll:

    This time I was using a WN. 500 & the 750. A little more wiring involve on this set up, but mostly due to the type of inverters and options to try. Normally I have the 750 feeding 4 SWEA 250's. So now I wired the 750 and a WN 500 from their rectifiers to a Sun 500 , 10.8-30 and also had the 750 connected to the SWEA for the high volts.
    I was really looking forward to seeing how this set up would work because the SWEA is tuned to start at 20 v so I was anticipating a big sharing of volts in that 20-30 range. Easiest way to say it , don't do it !

    It was interesting to see that the one Sun inverter was controlling both turbines with it's MPPT clamping down the volts on each. If you diconneced one turbine the volts stayed the same yet the watts dropped to approximately half. When the two different makes of inverters were trying to share those lower Volts there was great confusion and not very steady readings. When the volts did raise enough for the Sun to diconnect this automatically released the MPPT control of the turbines and there was such a high Volt spike this would shut down the SWEA from volt overload prtection and cause a braking of the turbine and of course lower the Volts again and now the cycle would start all over again with the Sun trying to disconnect and the SWEA saying it's too much !

    It was real clear that the SWEA inverter system had to stand alone. They were 4 separate inverters each tuned differently to work with each other, only.

    Next step was keeping those two turbines together to take advantage of the lower winds but this time I set up a disconnect on the 750 to allow it to feed the SWEA only when the volts increased nearer the 20 -25 v range.

    I also set up the dump load wiring for the first time on the Sun, feeding into 3 windy dump coils for when my wind increased and the Windy 500 produced more than the 30 volts. Now what will be interesting to watch when this happens will be if it goes into dump load I want to see if the MPPT is also disconnected, if it is this will release the turbine to create higher volts and force it to remain in dump load until the wind rpm decreases. It could end up in a lot of wasted opportunity in gathering watts in higher winds. ( this turbine does ave a furling system so hopefully that will help out )

    Our next shipment of inverters will be more 250, 500 & 1000. In these different ranges we also have a mix of front end and back end volts.
    We started out trying to see if using different combinations of inverters with MPPT would assist in low wind production and if by using these combinations we could verify that you do not have to purchase separate inverters for each turbine if you are using more than one.
    Neither of us have a sponsor to cover the cost of our testing, it would have been nice but we knew right from the start that probably everyone testing and experimenting were already under the spell of " what if I tried this "

    Man, I just realized how much I wrote ! Well Blue if Josh does set up a forum manager I guess we are going to make him work hard to keep up too us . :lol:
  6. bluejay

    bluejay WindyNation Engineer

    Love the breakdown of all the testing and I am cleaning up my board and will post a video soon of how I am running my gridties..I like the ensupras for the 12v systems and will slowly replace all my power jacks with these.. And for the 24 volt system I like the sun-g600's..

    But once again my question still went unanswered :lol: and I am going to run all my stuff the way i was and one positive on one inverter and the neg on another inverter,with all pos chained together and all neg the same way..
  7. murray2paddles

    murray2paddles WindyNation Engineer

    Your right ! I talked for an hour and did not answer you :roll:

    But, I do agree with you on wiring them in a chain to stack them and build watt amount.

    When you decide to change over what will you do with your pieces you don't want ?
    That is a question I have for myself, if I want to upgrade what to do or how to sell what I have !
    Don't really like to sell on EBay, but !
  8. bluejay

    bluejay WindyNation Engineer

    So you just answered YOUR own ? Mur..we need a classified/trading section here.... :D
  9. murray2paddles

    murray2paddles WindyNation Engineer

    1st, I do like he idea of having a classified buy and sell. I hope we can do more on that.

    Now back to your original thread question, you have us thinking about this for our testing also.
    I hope we can get some thoughts on this.
    If we are using a Sun DC 250 & 500 both @ 10.8-30 , The purpose would be hoping that combining these two we can combine then for a totsl of 750 watt !
    Can two inverters of same V range but different watt be combined ?

    If so please share your thoughts on the correct way to wire / stack them .

    I wom't even bother to write down all the different wiring combinations and theories that we have tossed around so far, we would rather just clam up and hope to hear from some of you first on your thoughts !
  10. dlmcbm

    dlmcbm WindyNation Engineer

    Here is a guy on youtube--- http://www.youtube.com/user/VWRabbitdiesel I have been watching him for a while now. He has a lot of grid ties of various makes and models. He has done a lot of testing on them with solar panels. He might be able to help you all out on some questions.
  11. bluejay

    bluejay WindyNation Engineer

    Mur I think by doing different wattages I would hook the 500 hundred up to the pos and neg up directly and then daisy chain the 250 off of it.. If you are dealing with all the same inverters(manufacturers}(which makes sense,made the same) I have had good success with how I stated on opposite poles coming into the end inverters.
  12. leamywind1

    leamywind1 WindyNation Engineer

    Hi Blue/Inquires:
    I will take a stab at possibly answering your question with maybe more then you may need.lol
    I have never treid to wire the inverters as you are suggesting.HMM
    The closest I have found to where I can get them to match production with using the same inverters is this:

    I have 220v line going to 2 seperate outlets dedicated just for the inverters only. 120v for each outlet from my main electrical panel for the A/C side. 10/3 wire
    I have (2) 500w Sun G GTI's D/C input 10-30v plugged in 1 per outlet.
    All of my turbines have their own rectifiers. All of the positives are joined on 1 pos. and 1 neg. buss bar comming from each rectifier same with the negatives. This is using 4 turbines.
    Afetr that i have two more buss bars pos. and neg.
    These bars are connected from all of the pos. turbine wires with a #6 wire, same with the neg sides.
    These two additional bars allow me to coonect up the inverters.
    Each positive from each inverter is then connected to the positive bar same with the neg. of this second set of buss bars.
    That requires 2 sets of #10 wire per inverter. 1pos. and 1 neg. per inverter.
    The second set of buss bars allow me to monitor over all volatge, amps and Wh's from what the whole combined system does plus again hooking up my inverters. it also allows for more inverters or even room for battery clamping. The two positive and neg from the inverters are set right next to the main feeders (pos.-neg.) on these buss bars to allow the most equal power distrabution off of those buss bars.

    At low wind speed yes one does start up earlier. It could be one or the other at times. I beleive this is just due to not enough power at first, volt, watts what ever the case. Once they both have enough to get started they seem for the most part to work together. One may be a littler higher with watts but within reason of the same production. They seem to start producing together as the wind-volts-amps increase. That is common electricity. Least path of ressistance. I have made 940 watts with two Sun G 500 GTI's for the top end so far. I was using a 24v battery clamp at the time because I did I not have enough inverters to keep more of a load on. This was in 20+mpH winds. I also have a wattsview data chart of this production. There is more testing to be done but the high winds are needed for me and Muarry to finish and they are just not there latley. I have a D/C input 1kw inverter comming 22-60V. The goal is to use a 250w 10-30v and let it join wthe the 1kw at the higher end. TBD. There are a lot of questions in this statement i know.

    I think with these inverters we will not see a perfect start up or perfect production match throughout. Even using multiple UL approved Enphase micro inverters for exsample with solar they still are not all a perfect production match. Closer then what we see with the China one's though. You get what you pay for. Personnaly I think to many people are reaching to far for the expectations of these inverters. They are what they are.lol

    It may be that instead of using dual inverters a single one may be more usefull. TBD (This is the quest Murray and I are on). Like when using a single solar inverter Sunny Boy, PV Power ect. Using the china inverters for everyone can be an expensive journey to get the rated power out of them and the truth is you really can not so we try to add more. This is where things can get screwy. So far I have had very good luck with running them this way. Daisy chaining them did not work for me for an efficiancy factor at all. The only piece of advice I can be sure of is that micro wind is not worth a UL inverter but solar is.
    I hope this helps in some way :D

  13. bluejay

    bluejay WindyNation Engineer

    Thank you Larry :D The logic behind more than one daisyed is because 1:
    I learned in the begining that with all the solar panels that the more powerjack 300w I added the more output I saw up until a certain point.
    2: With my sung-600w (have 2) it only made sense to me to daisy chain them because if you have a failure on one unit then the charge controller would be wasting electric.

    I did see one start to heat up under load but if the second was unplugged you could see some of the output go down. I will always daisy them all but like I said..power on the first to the pos terminal and the incoming power negative to the neg of the end(or 2nd if only 2) inverter..

    I agree with you about the UL for solar and that gets me thinking..If you have both and get buyback approval..Would it go on the numbers you call in(or they read) on your house meter or is it law that you have to have a second meter..you could slip you wind power into the house and would be a addition to your home meter readings so you would also be paid for that energy because your surplus would be on the books for the approved UL inverter,.... :cool:
  14. leamywind1

    leamywind1 WindyNation Engineer

    Hi Blue,
    I did not want to get off the subject of GTI for wind but my wiring method works for wind or solar in my situation. I think you are using batteries and switiching from battery power to grid tie? Very cool.
    Lot's of ways to wire that is for sure'. lol I have found that a back up battery system is better when it is spereated from a GTI situation. Less components and confusion-worries. I have two systems in place now, one for the grid and one for battery em. power. This is a whole other topic.
    You or you guy's will find this out when you go UL for solar.
    If you would like to PM on this we can exchanged a heck of a lot of information. To answer you last question, yes that is what i am doing. Also PM me on that if you need more information. There is just to much to explain in the forum. :D

    Here are some pictures of my GTI production regarding my last post and how they interact at lower and higher levels. I can only post two pics for some reason? I have a higher watt production picture but again it will not let me post the thrid one.

    This is a low wind start up with only one inverter working 5-6MPH

    This is when the wind is picking up about 8-9MPH you can see both inverters now putting out power about as even as I can get them. I will post the third in the 100w range next. Again this is only regarding wind turbine GTI production.

    I hope this helps

    Attached Files:

  15. bluejay

    bluejay WindyNation Engineer

    The batteries are only there for a load..There is a blocking diode so the turbine feels them but cannot draw off them The fuller they got over 22v the higher the volts would go (25-26v max, 22v draw from GT's)..The trip was at 26.00 but they always hovered around 23.72-24.14...Because the gt kept it clamped there was only small gusts of small juice to go into the batteries.All the rest were for the GT
  16. murray2paddles

    murray2paddles WindyNation Engineer

    Can you post a wiring diagram of your battery & grid tie set up showing your diode placement etc ?
    Do you use sealed / gel type batteries and where do you have your bank set up, indoors ?
  17. bluejay

    bluejay WindyNation Engineer

    10 guage solid copper,on a 12v system right now. Sealed agm 80 Amp batteries.The 900w dump + light is anchore into my brick chimeny out of the picture. Also just out of view on the right is 2 ensupra 12.8v GT's.Ones silver(500)and a black(550) new.Also further down yet on another circuit(does have a frezer on it also) is where my solar (4 x 300w) have been hooked for almost a year..[​IMG]
  18. murray2paddles

    murray2paddles WindyNation Engineer

    Thanks Blue
  19. bluejay

    bluejay WindyNation Engineer

    that still wasnt done fully but ..Basically every turbine will have one terminal feed to the battery and one to the grid ties.Its hard to see but that feed where it goes from the 10 g theres a diode and then the large 4 gauge wire goes down to the batteries under on a shelfing unit..

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