Newbe Generator Question

System
System Posts: 2,511 admin
in Off Grid Solar & Battery Systems #1
We are new to solar, but do have our system up and running. We currently have 9 panels for about 2000w, and outback charge controller, mate, flexmax 80, and 16 6 v crown batteries.
We are a little confused because our system came with a transformer and bypass assembly. I think the bypass assembly is for a second inverter and the transformer for hooking up a 240 generator, but clarififation here would be great. What we are trying to do now is hard wire a generator in. Our gen is 8000w, but will be a manual start. are there breakers involved in this or can we just run the hot from the gen to theac input let 1, and the neutral and ground to their respective TBB? we have 25a breakers to the transformer, but there are no free slots to hook up the gen there.
any input would be great!!!
Thanks so much,
Curt
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Newbe Generator Question

    What model of inverter/charger do you have? Some of the inverter/chargers have problems when trying to synchronize to a generator (were designed for grid power with a more stable frequency).

    Regarding grounding--here are a couple threads:

    Generator system ground vs chassis ground
    Towards the end of this thread is a very nice discussion of proper generator grounding.

    You have to check how your current AC and Safety grounding are currently wired up... You want to avoid having a neutral bonded both to safety ground in the house and in the generator (generators >~5kW usually have the neutral/earth bond inside the genset).

    You don't want more than one point where earth and neutral are bonded together--you can get current flowing in both the neutral and earth ground--and if you use AC GFI (ground fault breakers)--the ground loops can cause GFI Breakers to trip.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • System2
    System2 Posts: 6,290 admin
    #3
    Re: Newbe Generator Question

    we have a outback flexware 500 with a VFX3648. It is supposed to be generator ready, we are just confused on the ac input with it.
    Thanks!
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  • hillbilly
    hillbilly Solar Expert Posts: 334 ✭✭
    #4
    Re: Newbe Generator Question

    The "bypass assembly" sounds like it might be a transfer switch, which would be two circuit breakers mounted in opposing directions and tied together so that which ever way it's switched one is always "off" and the other would be "on". The idea is that you don't want to connect two AC power sources together; in your case the Inverter's output, and the generators output. I'm a bit unsure of the whole setup you're describing, but I think Outback should have some wire diagrams on their website (I'm kind of surprised that they didn't include some with your purchase, they did with my inverter). If not, I know that Midnitesolar.com has a nice, easy to follow diagram for their E-panels (which would likely at least give you a better idea how things should be protected, ie where you need breakers).

    I'm not sure how the transformer will play into this, as I'm not sure if you're using a 240V generator or 120V, or if this is just one inverter or two. There are some options as to how to configure that depending on what you're doing. You do want a Breaker on the Generater AC input side of things, not sure about not enough spaces...?
    Check out some of the wiring diagrams, hopefully that will clear up some of the questions.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: Newbe Generator Question

    I certainly have little direct knowledge of the Outback products... However, their website does have a nice set of drawings documenting various configurations--Perhaps one of them can help?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • E-dub
    E-dub Registered Users Posts: 13 ✭✭
    #6
    Re: Newbe Generator Question

    Yes, as Hillbilly mentioned the bypass switch is for "bypassing" the inverter if there is a problem so you can run the house straight from the gen.

    Also, Outback usually has detailed wiring instructions on the inside of one of the panel covers. These are usually in nice detail. Otherwise, shouldn't the AC hot from the generator go the bypass assembly? The hot from the bypass would then go to the AC Input 1 on the inverter. The same for the neutral.

    If you want to skip the bypass then, yes, the generator hot goes to AC Input 1 and gen neutral to AC Neutral In. However the question is, do you have 1 VFX3648 and is there no AC breaker box? If you have the AC breaker box (on the left side of the inverter) then you need to start there with your generator hot/neutral inputs.

    Rick
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  • blackswan555
    blackswan555 Solar Expert Posts: 246 ✭✭
    #7
    Re: Newbe Generator Question

    The diagram at the bottom of the page of BB`s suggestion "X240 gen balancing" outlines, But it is dependent on,
    A. Your gen, Is it single phase or dual/split ? eg 110v or 220v or both ?
    B. How many inverters you have ?
    C. Your loads, again single or dual/split ? 110 or 220v ?

    How "pre" wired is it ? (Some pics would help) But if is fully, You would normally be looking for the "AC HOT IN" bus bars fitted to the back of the enclosure,

    Have a good one
    Tim

    PS A post on the outback forums may be useful, http://outbackpower.com/forum
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