xw-mppt 60 installation problems

Dapdan
Dapdan Solar Expert Posts: 330 ✭✭
in Off Grid Solar & Battery Systems #1
Hey all,

Can anyone assist me, I am have some problems with my new xw-mppt. I have connected everything as instructed by manual and I am getting a fault message on the CC when I connect the battery. It is saying "fault active" and not going into the prompt screens as the manual describes.

Any help would be kindly appreciated.

Cheers...
Damani
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Comments

  • nigtomdaw
    nigtomdaw Solar Expert Posts: 705 ✭✭
    #2
    Re: xw-mppt 60 installation problems

    Just an early thought,do you have a negative battery earth bond, as I did in my system, if so try removing the groung fault protection fuse in the XW60 then see what happens. My system has a Neg Earth bond and that was X's response.

    If this cures the XW bootup fault fine, but Im not advocating this is your final solution just showing u a possible cause, as Im not covered by the same electrical code as the US is. You may then have to redesign part of your system to allow the XW60 MPPT to utilise its GF fuse protection system .

    The above is only my suggestion and please seek further advice b4 continuing.

    Nigel
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #3
    Re: xw-mppt 60 installation problems

    Nigel is probably right as usual....Your negative battery cannot be connected to earth ground as the XWCC will do this and provide ground fault circuit interuption of PV.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: xw-mppt 60 installation problems

    I may be wrong--but I thought you can negative ground the battery bank with an XW CC just fine. I am wrong--there is a Ground Terminal on the XW CC Charge controller that goes through the 1 amp Ground Fault detection fuse. That is the only "CE" approved method of grounding the XW CC.

    [remove incorrect statement on grounding]

    Check the PV Array connections. They should go directly from the array to the one Charge Controller with no extra connections. Check there are no shorts between the positive array lead and ground. No sharing the array between other charge controllers, etc.

    Lastly, if the XW CC uses a 1 amp ground fault detection fuse (I think it does)--make sure that the fuse is not blown and it is properly installed. The CC should "detect a ground fault" if the fuse is blown/missing/broken.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #5
    Re: xw-mppt 60 installation problems

    Bill,
    The negative ground point is at the XWCC and only at the XWCC. Many systems have negative ground at various places and adding an XWCC to an existing system will and believe me does cause this error to be displayed if there are other bond points.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #6
    Re: xw-mppt 60 installation problems
    BB. wrote: »
    I may be wrong--but I thought you can negative ground the battery bank with an XW CC just fine.

    You can - sort of. It has to be grounded through the controller ground terminals though. See page 13 in the manual http://www.xantrex.com/web/id/1876/DocServe.aspx
    Note that both the panel negative ground and the battery ground go to the ground lug on the controller, and then all grounds go to the main system ground bus terminal.

    The idea is that you want a single point ground, or you can get ground loops, or false triggering of the GFI - or both.

    In low voltage systems with a standard controller you can often get away with grounding the battery negative and the the panel negative (though still not a good idea) seperately (though still not a good idea). Single point grounds have been pretty much the standard for decades, but until recently most PV systems could ignore it and get away with it.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #7
    Re: xw-mppt 60 installation problems

    If the OP wants to run the XWCC in his system as wired he can defeat the GCFI by removing the jumper in the wiring bay. I forgot about this as it is not a good idea to do this. This jumper is the negative battery bond internal to the XWCC.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #8
    Re: xw-mppt 60 installation problems

    While you CAN defeat the GFI system, the real problem can come from ground loops, and possibly lightning hits.

    Aside from some false readings on some systems, ground loops can also cause severe galvanic corrosion if any metal is touching the ground. I lost the pictures I took, but a while back we repaired a system where the customer had used a metal fence as a ground, and all of the metal posts in the ground were totally eaten away.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #9
    Re: xw-mppt 60 installation problems

    You guys are correct... While you were typing, I went and found the grounding manual and the Xantrex XW CC does require grounding through the one "ground terminal" on the controller.

    Boy, this is sure a change from the NEC's previous theories on safety grounding... Before, the "safety ground" had to carry 100% of any short circuit such that a protective device would be tripped (fuse, breaker, etc.) and stop the current flow.

    Now--a 1 amp fuse blows to stop the "ground connection" but everything is still energized--but you get a nifty Red LED to tell you something is wrong...

    End of DC ground fault detection rant. I will fix my above post (always read the manual first :blush: )

    Here is the tech note on positive grounding (which removes the GF fuse and disables the fuse detection circuitry) and allows the battery to be grounded (in either positive or negative ground).

    The jumper just disables the fault detection (I believe). Removing the fuse (or blowing the fuse) "lifts" the ground connection inside the controller).

    Back to the manual, Fault Active says:
    Fault Active: A fault condition is present (see Active Faults and Warnings screen). For more information about the fault, press Enter to view the Active Faults and Warnings screen.

    So pressing "Enter" does not work?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #10
    Re: xw-mppt 60 installation problems
    Windsun wrote: »
    While you CAN defeat the GFI system, the real problem can come from ground loops, and possibly lightning hits.

    QUOTE]

    Hopefully no one will ever get to experience what ground loops can do to a boat thousands of miles from shore in seawater. The OP should use the GFI as designed. He paid for it in the price of an XWCC, might as well use it!

    Bill,

    There still is a #6 wire from the earth bond to negative, there just is not any PV output or input to the CC in a fault.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Dapdan
    Dapdan Solar Expert Posts: 330 ✭✭
    #11
    Re: xw-mppt 60 installation problems

    Hey guys,

    Thanks for the in depth response as usuall. Here are some point of fact of my system:

    1. I have one grounding point that is shared with all the CC (c60 and now xw) and the inverter.

    2. I don't have the battery negative bonded to earth.

    The up side is that I solve the problem (or maybe I think I solved it) I went through the menu and realised that the CC did not automatically picked up the system voltage (as it said it does) and It was at 48v instead of 24v so I changed it to 24v manually and I was able to complete the commissioning of the CC and observed it harvest through out the day. It certainly is a significant improvement on the previous C60. Basically 8 panels into the xw is nearly the same as 10panels into the C60 (comparing today to yesterday)


    Again thanks to all you guys for the input and I will have a read on the manual again especially on the ground loop, GFP and negative bond issues.

    Cheers...
    Damani
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  • dsp3930
    dsp3930 Solar Expert Posts: 66 ✭✭✭✭
    #12
    Re: xw-mppt 60 installation problems

    I have a similar question on grounding ...

    Background:
    - The GFI jumper (pins and all) is NOT installed on my SCC. Must not have been part of the board revision.
    - I have the GFI fuse removed (since there was no jumper)
    - I have the Midnite 63A DIN GFI breaker installed for GFI protection as per Midnite instructions inside my E-Panel (Distribution Panel)

    Is this setup adequately providing a battery ground?
    Am I correctly GFI protected?

    As a side note ... I have the Delta lightning protectors on my AC1/AC2/Load bus, PV bus, and in my PV combiner box. Has anyone taken a lightning hit and been able to attribute one of these doodads with saving their system?
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