Newbie Wiring Diagram Reality Check

Discussion in 'Wiring Methods' started by Chris McCaffrey, Dec 4, 2012.

  1. Hi All,
    Here's a diagram of how I've got my turbine wired. It is based on the Xantrex Controller diversion mode diagram + my interpretation of where to put the rectifier and meter since those aren't included in the Xantrex diagram. Does this look right? Is it OK to have single wires down to the battery, then use one of those metal bars w/ screw holes in it to consolidate? Multiple wires down to each battery post was creating a mess.
    Sunapee wiring 1.png
    What I'd really like to do is add a grid tie inverter as below. Goal is to 1st charge the batteries, then if they're full go to the grid, then if the grid is unavailable or there's greater than 500w, go to the dump load. Any advice is much appreciated!
    grid tie.png


    Attached Files:

  2. leamywind1

    leamywind1 WindyNation Engineer

    Hello, Maybe I can help?
    Your diagrams look good/correct. The only problem is see is you must make sure the dump coils do not exceed 16 amps as the GTI dump relay is only rated for 16 Amps. Using a 24v battery system you could dump lets say using 24vdc (coils) x 14 amps =336 watts. So if your turbine is 400w or more you may fry the relay in the GTI when the grid goes down upon a big gust. There is a chart for these dump coils/relays on this forum some where. I am speaking of the wind rated China GTI's of course just to confirm

    Instead of using the GTI dump controller you may want to use an external relay instead. Dumping when the bats are full is a grat idea but again that little relay in the GTI is not to worthy as many find out the hard way.
    I run all GTI's (no bats) and they are all run 22-60VDC GTI's with 48v coils. 600w worth of coils x 48v is 12.5 amps per 1kw turbine. So if the grid goes down my birds still spin up to 48vdc before they see the load fo the coils
    The other option is to us a 10-30vdc GTI on the load side of the watt meter, put a diode in so it only sees the turbine voltage. This will allow no back feeding of the 24v bat bank (pos side) to go into the GTI. If the GTI gets to 24vdc then it will share with the batteries (battery clamping), if it gets to 30vdc or overvolt your CC will dump. If the grid goes down then your CC will run the show. If your CC is set for 28vdc to dump then it would dump at 28vdc keeping things well under control. This may be a more economical way to go. However it would be going to the grid first 99% of the time this way.:)
  3. Leamy, I got a question on the dump load amps for you. If I have 3 of the china 500 watt grid tie inverters hooked in parallel (24-60 volt) using a 1000 watt dump load coils would I still burn out the 16 amp relays in the inverters? Running 3 - 800 watt 24 volt turbines hooked in parallel to 3 - 500 watt 24-60 volt sun grid tie inverters. The connection to the dump is made through the last inverter in parallel. Help would be appreciated. Thanks
  4. leamywind1

    leamywind1 WindyNation Engineer

    Just to clarify. You want to run (3) 800w turbines to (3) 500w GTI's all in parallel. Then use 1 inverter dump system at 16 amps off one GTI for the full dumping of all three turbines letting 2 0f the tree inverters goto overvolt while the one takes care of all dumping? So, the other two inverters dump controllers are not being used? Using a total of 1000w dump coil. If you are dumping at 60 VDC and you use 48v coils or coil that would be roughly 1000w/48v which is 20 amps. I would imagine the coils want to pull the turbines right down to 48 vdc. That's how mine are working but i use 600watts per GTI, not 1000w as that is too much for the GTI relay. My relays are far. I do not dump alot becuase my winds do not get above 25 MPH ( i did have a great test with Hurricane Sandy 55MPH winds) that much but i do know to stay below 16 amps on the GTI's dump relay. I have opened up every GTI from Sun G (wind rated) from 250 to 1kw and they all are 16 amps. I have all of them. lol You could use all three dump controllers (1) per GTI which would be better in a parallel set up, (300 w coil if you are using the WN type) per inverter at 48vdc with 22-60v GTI's. You could also use a 300w coil at 24v 1 per GTI using a 500w 22-60v GTI that's 300w/24v=12.5 amps. I am just using WN coils as an exsample you may find other ones that do better with the math. Last suggestion is you could contact the manufacture abotu all of this too.LOL

    The thing is running the inverters in parallel I have found do not work to good. You do not get the full output per turbine for an overall. Keeping each turbine seperated from one another seems to work the best with these inverters and their MPPT-steepness power curve. However you can still keep them seperated to their own GTI plus send them all at the same time to the batteries. It's a tricky system but it can be done using blocking diodes. Right now I have all 3 of my turbines going to a 250 w GTI 10-30v but each turbine also has it's own 1k 22-60 GTI so they are sepreated for the 22-60GTI's but joined together for the 250. This allows me to collect more low winds as well as get the maxium output out of them as each turbine will have it's own inverter up around 14 MPH winds. That's when the little 250 has enough and goes to overvolt. Each one running at a higher volatge at that point. So you could do the same thing with your batteries too. I also assume you are using (3) WN 750 PMA's?

    I do understand your piont of why you want to only use 1 inverter to dump when wiring them all in parallel. I am just not sure if 600w at 48v coils would keep all (3) (2400 watts) turbines under control.

    Does this help ya?
  5. Thanks for that heads-up. To make sure I understand - I've got 4x 24v 300watt resistors that each handle ~10amps, so that's 40amps capacity. The relay in the China inverter can only handle ~16amps. In a big gust my 750watt 24v turbine would deliver 30+amps and if the controller is bypassing the full batteries the current would go into the China inverter and fry the relay. Does the China inverter dump only the excess after 500w or does it dump everything. And is the relay handling all of the electricity going to the inverter all the time or just when dumping? What if I buy a 2nd inverter and install it in parallel and have both inverters wired to the same 1200w dump load, or break it into 2 coils for each inverter? If each inverter has a minimum amperage to start, would I then be doubling the wind energy necessary to get anything going to the grid?

    Side-bar question - you mentioned the batteries back feeding the inverter. Is there a way to do that on purpose on weekends when I'm and at the cottage? (this is to ease my paranoia of having my system connected to the grid when I'm not there). So the notion is I'd fill the batteries when away, then discharge them into the grid when there?

    Thanks for your expert advice!
  6. leamywind1

    leamywind1 WindyNation Engineer

    Hello Chris,
    Does the China inverter dump only the excess after 500w or does it dump everything.
    Usually it just dumps when the volatge exceeds it's limit. It's based of a volatge limit not amperage. The steepness -power curve in them are already factory adjusted so you have to hope for the best regarding which turbine you use with them vs the power curve. Basickly it takes a sh$% load of testing per turbine to get it to work just right.

    And is the relay handling all of the electricity going to the inverter all the time or just whewhen dumping?
    Yes, the inverter disconnects and sends all the DC power to the dump load coils at an overvolt and then reconnects when it is satisfied under it's voltage range.

    What if I buy a 2nd inverter and install it in parallel and have both inverters wired to the same 1200w dump load, or break it into 2 coils for each inverter? If each inverter has a minimum amperage to start, would I then be doubling the wind energy necessary to get anything going to the grid?
    One inverter will always take charge before the other so runing them together does not work well. you do not necessarrly need twice the power as one will lock on first with it's MPPT. What will happen is one inverter may goto dump before the other, then you are left witht the same problem of only a 16 amp coil load. I know they say they are stackable but that is per turbine, not multiple. The best way is to seperare each turbine to it's own GTI. I know that cost more money but that is the right way as most are now doing including me. I have tried multiple inverters. The only other way is to not use any of the dump load controllers at all, buy a relay that can trigger at 60vdc, have that relay work a 24vdc relay that is rated for 40-60 amps and connect that to all the coils. The 60vdc relay would be in parallel with the GTI's and turbines. Then you can dump upto a 40-60 amps of power, the power from the 24vdc relay would come powered from your bat bank when the 60vdc relay closes. now you could hook multiple relays to the main relay and dump as much power as you want. just make sure the 60vdc relay can handle the watts required for each 24v relay. the 60vdc relay must also beable to handle a volatge fluxuation to. i know they are out there as Tom on this forum is using one for his system.

    Yes, there is a way to make it work as you say regarding having the turbines keeping the bank charged and switch it to GTI's when you are there. I can do you a drawing if you would like just tell me how you would like to run it in detail. The drawings take some time to do so if you want one please think it over first and then let me know. PM me. Just remeber the more options you want the more expensive it gets.

    I hope this helps
  7. Mr. Leamy (not sure what your first name is?),
    RE the suggestion of an exernal relay to switch power to dump load, I like that idea, but even the big electrical distributor near Boston didn't have such a thing for 24v circuit. If I get your suggestion, what I'm looking for is a relay that switches based on output from the turbine exceeding 500w, right? (so I don't fry the Sun inverter). Can you clarify what I should be looking for?
  8. leamywind1

    leamywind1 WindyNation Engineer

    My name is Larry. Yeah most electrical supply houses even in Pa will not have the DC parts we all need for wind. Ebay or other web sites is where you will find them. This is a control modual i am speaking of used with an extral relay and you can dump as much power as you want to waht ever your extranal relay is rated for. Set the main modual for like 54-55VDC to trip\-your discretion.

    For example have it pass 12vdc off a 12v bat bank or what ever DC power source you have to control lets say a 40 amp 12v relay, that 12v relay is connected to your dump coils-load. Run the modual in parallel with your DC input of the inverter. The modual sees the 55vdc from the turbine, closes pasing 12vdc to a NO 12v relay. That relay then closes when it gets 12vdc and will connect your dump load. A 12v car realy at 40 amps is like 10 bucks or less at any automotive store.I can suggest you may want to PM Tom on this forum as he is doing just this and may be able to add some insight on how it is working for him..

    Please read more on it from the link i have posted.
    Voltage Controlled Switch
    Check this out for help

  9. TomT

    TomT WindyNation Engineer

    This is the same one I use to turn my car solenoid on and off. The solenoid is hooked to my dump load. It also is cheaper than I saw at another web site.
  10. Hi. Thanks Larry & Tom. Still getting my head around this. Larry, you've warned that the relay in the inverters only handles ~16 amps. Do you know if the relay in the Xantrex controller is similarly weak? Hopefully not!

    Setting that aside for a minute, If my goal is charge the bats, then when they're full switch to the inverter, then if the grid is down or the wind greater than the 500w inverter can handle w/ my WN 750 go to 4x 24v dump loads, couldn't I use my Xantrex C40 charge controller to switch from batteries to inverter at 28v, then the voltage controlled switch you reference above to go to dump load at 60v to avoid frying the inverter? For the voltage control switch I'd want to get the "Active High: Relay activated when voltage goes over high setpoint" version, right? And I'd get the 24v, 30amp relay with that, also from the link above. Is 30 amp too low if my 4x dump load coils are rated to 50 amps (4x 300w 24v coils = 1200watts/24v = 50amps.)? Not sure I'd ever get that much out of WN 750, but I got 4x coils just to be safe.
  11. TomT

    TomT WindyNation Engineer

    I fried the first relay in the voltage controlled switch and had to replace it. That is why I have mine hooked to a heavy duty relay. I do use the active high voltage switch. It has to be run from a separate battery to work. I run mine off a small tractor battery. Put a charge on it every few months or it will drain it down.
    The dump load coils as you add them in parallel will lower the current flow through each resistor and also lower the resistance. Which works as a brake the more you add while keeping the coils cooler. Like mine. I had 600 watts and it would not slow the turbine down and the coils were getting hot during wind storms. So I went to 900 watts and now it slows the turbine down and the coils run cooler.
  12. Just curious, is there any physical difference between a WN 24v and 48v resistor? Thicker element?
    Anyway, if I've got 4 of the "24v" variety and a WN 750 watt turbine, how do I speculate the max amps I'd need the relay to be able to handle? Say the turbine gets to 1000watts in a gust, that'd be ~ 1000watts/24v = 41.6amps, right? So is a 30 amp relay going to handle the peaks? Or will the 4x resistors keep the thing so slow it never gets the rpms necessary to produce much power? Certainly looked slow as molasses when I connected the turbine directly to the resistors and I felt no heat.
    Thanks, as always for your input.
  13. leamywind1

    leamywind1 WindyNation Engineer

    "Any physical difference between a WN 24v and 48v resistor? Thicker element?"
    Not sure you may want to ask Josh that question. I have all 48 v coils

    I would go with at least a 50 amp relay or two 30 amp relays in parallel. 30 amp relay getting 41 amp may fry the contacts shut.

    Tieing the turbine right to the resistors is not allowing it to get up to speed, remember when it dumps it running at 800 rpm's and that is where your high amps are/heat.

    Just my 2 cents.

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