Multiple inputs, wind & solar circuits

stmar
stmar Solar Expert Posts: 370 ✭✭✭
I have a junction box where my wind turbine and solar cables come into my system. Should the negatives be on the same terminal block or should they be isolated from each other? I have 3 circuits, 2 wind and 1 solar.

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Multiple inputs, wind & solar circuits
    stmar wrote: »
    I have a junction box where my wind turbine and solar cables come into my system. Should the negatives be on the same terminal block or should they be isolated from each other? I have 3 circuits, 2 wind and 1 solar.

    That depends on what you mean by "wind turbine and solar cables". There's more than one way such could be wired up, and it has to do with how the charge controller(s) fit(s) in.

    Some examples:

    1). A very simple small system may have turbine and solar feeding directly to the battery and a single dump controller attached to that does all the regulation.

    2). A more complex system has a separate charge controller between the solar and batteries, the turbine feeding the batteries directly, and then a dump controller regulating the battery Voltage.

    3). A very complex system has a charge controller for the PV array and another controller and dump load for the turbine.

    Eventually the positive and negative from both the solar and the turbine will meet at the batteries. It's a matter of detail as to how they do it.
  • stmar
    stmar Solar Expert Posts: 370 ✭✭✭
    Re: Multiple inputs, wind & solar circuits

    Mine is more like #2. The solar goes through a ProStar30 controller and the wind turbines have internal regulators, Air X 403. At this time the wind turbines are down and this would be a good time to rethink things. I have a dump controller but have not installed it, did not know if I needed it.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Multiple inputs, wind & solar circuits
    stmar wrote: »
    Mine is more like #2. The solar goes through a ProStar30 controller and the wind turbines have internal regulators, Air X 403. At this time the wind turbines are down and this would be a good time to rethink things. I have a dump controller but have not installed it, did not know if I needed it.

    In this case the output from the solar charge controller and the output from the turbines come together at the batteries. I'm not sure how good the AirX regulation is; never heard of anyone having any luck with them (except for one that was extensively modified). Frankly you shouldn't expect much from them.

    If when connected you find the turbine is pushing the battery above the Voltage limit then you need the dump load controller. When one of those is used it is the 'ultimate' controller for charging the bank as it will limit the input from all sources. That means you sometimes have to make fine adjustments to get the actual Absorb Voltage you need, and not all controllers have such fine adjustments. It also needs to be able to handle the full output power of all sources, and technically the NEC requires two such diversion controllers - because they always think this stuff doesn't work.
  • stmar
    stmar Solar Expert Posts: 370 ✭✭✭
    Re: Multiple inputs, wind & solar circuits

    I am not in a hurry to put the wind turbines back in action. We have strong winds in Wyoming and I have not had good luck keeping the turbines intact. Now that I have the EU2000 it makes the turbines even less desirable. But I do have one I repaired so may play with it at a later date along with the dump controller. When I finalize my generator plug/circuit I think I will isolate the negatives from the solar and wind cables just to be on the safe side. Thanks for the input.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Multiple inputs, wind & solar circuits

    And as a precautionary note, whenever you do connect to wires together make sure the result can handle the current. In this case two power sources coming together: one supplies 'X' Amps, the other supplies 'Y' Amps and after the connection the current will be 'X+Y' Amps. The wire from that point on must handle that much.