tieing two or more mills together

Discussion in 'General Questions' started by irv, Aug 23, 2010.

  1. irv

    irv WindyNation Engineer

    I plan on putting 3 to 5 SMALL mills on the top of a large barn . the question is , what is the best way to wire them together for a common output ?
    the barn is 30 high , 100 foot wide and 120 foot long , so these mills may be about 40 high . the goal is to run all the lights in the barn plus // thanks Irv
  2. BeachBum

    BeachBum WindyNation Engineer

    I can only tell you what I would do if that were my barn. Based on what you described you have lights right now. That being said, you probably have a separate power panel in your barn. If it were me, I would not go to the expense and effort of creating a battery bank. I would probably use a combiner box (waterproof sub-panel) on the roof, and run the appropriate size Romex (maybe #8) down to the panel, to a grid tie inverter, then to the appropriate size breaker in the panel. I would backfeed the grid to store the power I produce on the utility pole.
    Check with your utility company about the rules for doing this first. Most will let you do this with the correct "UL Approved" grid tie inverter. SMA Windy Boy is a good choice for the size system you described, but there are many others (just not many for a turbine array of that size using one inverter). You may choose to use separate inverters for each wind turbine, like the SWEA unit or the ebay unit from China. If you plan to build a hybrid system using batteries that is also tied to the grid, Outback makes an excellent unit. If you plan to live dangerously and make this install without permission, I would at least have an experience electrician check everything (especially wire size) so you don't burn your barn down. ;)
    Good Luck,
  3. murray2paddles

    murray2paddles WindyNation Engineer

    Hi Irv,
    Well I don't have a barn but from all the mistakes I have made already I would step back and count how many lights you have now in the barn, what is their watts per light and how long per day will they be used. ( average taking into account short winter days ) Then what else are you hoping to run and figure out the watts required per day for those items then you will have an approximate total hydro required.

    Sounds like a chore but then you will have a better idea on what size of turbines will be required to meet those needs and then you can make a more informed decision on how best to use that hydro !
    " To grid tie or use a battery bank " When you have decided that then you will be able to ask how best to tie them together.
  4. irv

    irv WindyNation Engineer

    Hi Guys / and thanks , but I dont think I asked the question correctly , how doe's one WIRE one turbine or more , such as the NW 500 together for a single output ? exsample , you have two 500 watt max mills and you want one 1000 watt max output . must you convert all mills to DC and then combine the DC and then go to a charge control and then to batterys and then to a inverter to get AC ???? What is a good way . I dont want to grid tie , Thanks again /IRV
  5. BeachBum

    BeachBum WindyNation Engineer

    Murray is right about calculating your load requirements. You will need to balance this with your battery bank. Murray has a lot of experience with batteries and multiple turbines. As for the thought of converting to DC, I won't. DC requires fat wires for short distances. I would stay AC until I had to go DC at the charge controler. What do you suggest Murray?
  6. bluejay

    bluejay WindyNation Engineer

    I would run both turbines wild ac to each of there own rectifiers on your board then the dc could be safely combined into the battery bank.
  7. murray2paddles

    murray2paddles WindyNation Engineer

    I agree with bluejay. after the separate rectifiers feeding into the battery bank the same dump load will take care of the bank.
    But still figure out what your needs will be 1st. This will help you determine the size of turbines you will require and really important the amount of batteries to give you the amp hrs needed.

    Hey Beach, did you get the note from me on your anemometer tower project. I need to learn from you.
  8. BeachBum

    BeachBum WindyNation Engineer

    I've been out of town this week, and wanted to respond to you properly, with some photos. I believe my unit is made by Taylor. I got it online through Target.com. I'm pretty satisfied with the the system so far. It does have a wireless display that I mounted on the wall in my house. I know there is another company that sells wind meters at Home Depot, if you have one near you. I'll try to include some links so you guys can look this up. I will definately sent you more info when I get home. Sorry I didn't reply on private, I'm in a seminar for solar installs this week.
  9. BeachBum

    BeachBum WindyNation Engineer

    They're calling it a Taylor Wireless Weather Station with Anemometer
    Here's the link:
    If the link doesn't work, just go to target.com and search "Taylor wireless Anemometer"
    The cost is $79.99
  10. murray2paddles

    murray2paddles WindyNation Engineer

    Thanks Beach, I have it bookmarked now. Good to hear you were pleased with it.
    Do you know the wireless range ?
    What height pole did you use ?

    To have an accurate reading I suppose I should be putting it up as hight as my turbine towers !

    Traveling today so will have a chance to check out a Canadian Home Depot. Seems as though they really stock different products for different parts of N. America.
    Good to hear you were at the solar symposium. Learn lots so I don't have to. lol

  11. windyguru

    windyguru WindyNation Expert

    Hi guys,
    I too have been traveling all week. Just got back very late last night.

    With respect to Irv's question, I would agree with what everyone said. Run 3-phase AC from all your separate turbines as far as you can. The 3-phase bridge rectifiers should be mounted fairly close to the battery bank (Less than 10 feet will be fine. Check a wire guage chart for the wire thickness needed after you rectify to DC. You should be fine with 8 gauge per turbine if you are only running the wire a couple of feet).

    Each wind turbine gets its own 3-phase bridge rectifier. After you rectify each wind turbine, you can tie the DC output wires of each turbine together. At this point you have a choice. Do you want to tie the turbines together in parallel or series. Tieing the turbines together in parallel, will add the current (amps) of each separate turbine together (i.e. two turbines tied in parallel each making 4 amps at 12 volts, will give you 8 amps at 12 volts). Connecting two turbines in series will add the voltage of each separate turbine together and the current will stay the same. REMEMBER this should be done AFTER you rectify each turbine. You can connect as many turbines as you want in this manner and you can do a combination of series and parallel wiring if you have more than two turbines.

    One last note, as you tie more and more turbines together in parallel, the current traveling through that wire keeps increasing. Keep this in mind. If you connect five turbines together in parallel, you are going to need a wire that can handle ~200 amps. That is going to be thick and expensive wire. Now you can see why it pays to do this as close as possible to the battery bank.
  12. irv

    irv WindyNation Engineer

    Thank you all /// very helpful ,
  13. murray2paddles

    murray2paddles WindyNation Engineer

    when you said 3 - 5 smaller turbines, what size is smaller ?
  14. irv

    irv WindyNation Engineer

    I am using a windy 500 , I have one running , and will buy another . I live in central Oregon and that size mates with the wind here very well , also
    my pocket book . 15 to 20 mph is a nice wind here ( there is almost always a light wind here) , 25 to 30 is a hard blow , the only time it goes over that is if we have thunder storm. I am now building a new frame and will gear the windy 500 up just a little . will post picture when runing .When I have a good match ,turbine to wind , I will tie some together . I think small but many well work well on this farm . /// thanks , Irv

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