Xantrex Mppt issue

Hi all.

I am relaying this on behalf of a friend of mine who is and experienced solar installer with some problems with the Xantrex XW60, even the repair service couldn´t help on this.
The thing is that with this model ( 2 units the same problem ) the system just load 10A while with an Outback 60 it goes to its maximum. With the menu nothing helps even changing the grounding to none or reseting the batteries voltage.
Any idea about this problem ,firmware bug or something?

Thank you in advance.

Comments

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex Mppt issue

    Check the Ah setting ( battery capacity ), make sure the unit is not is absorb or float modes, that you have remote temperature sensors on both the OB and XW units and does this happen only when both units are connected or when the also run alone?

    If your still have issues, note the array, battery voltage and current levels and charger state .. with those you should be able to understand what is the cause of the limited performance

    I've recently done some very exhaustive competitive testing on both controllers for a client and the XW has not shown any obvious bugs or flaws
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    Re: Xantrex Mppt issue

    The only obvious thing I could suggest without more data from your friend and you restating the problem (hard to understand) is that the Outback units do not have GCFI and the system is negative bonded at the inverter. You can not have the negative bond at the inverter on the XWCC as it provides the bond.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Malasombra
    Malasombra Solar Expert Posts: 24
    Re: Xantrex Mppt issue

    Thank you both.

    Afaik this happens with just one 1 unit working at the same time. Changing the xw to the ob the power goes rocketed.
    He told me the that the ground option is OFF if it helps. I will tell him your ideas and recheck the grounding points and bonds.

    Thanks.
  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Xantrex Mppt issue

    the Jumper that you say is off is a separate issue the neutral or ground from the solar panels needs to go directly to the controller and not be bonded to battery negative if it is you will get weird results
  • Malasombra
    Malasombra Solar Expert Posts: 24
    Re: Xantrex Mppt issue

    Hi all

    The panels structure and the inverter ( ground wire ) are the only items with grounding. No negative wire to ground, no where. And checking the specs in spanish says the XW is only for negative-grounded systems ( english version is different about this ) , so after a big D´Oh we will see how this affects this issue.

    Regards
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex Mppt issue

    The XW-Mppt is a 4 wire Mptt controller. The Solar Panel leads must ONLY connect to the chargers "+" and "-" solar input, not anything else. Then the output of the chargers "+" and "-" go to the battery's

    Not connecting earth ground to the charger will have no effect on performance, it only for the US NEC electrical code for having ground fault protection on the array wiring

    Sounds like the controller is wired where the solar panels "-" is connected directly to the batterys "-", that will not work with XW-Mppt but will with the Outback unit
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    Re: Xantrex Mppt issue
    The XW-Mppt is a 4 wire Mptt controller. The Solar Panel leads must ONLY connect to the chargers "+" and "-" solar input, not anything else. Then the output of the chargers "+" and "-" go to the battery's

    Not connecting earth ground to the charger will have no effect on performance, it only for the US NEC electrical code for having ground fault protection on the array wiring

    Sounds like the controller is wired where the solar panels "-" is connected directly to the batterys "-", that will not work with XW-Mppt but will with the Outback unit

    Very true and my point since this unit is not working the OP may have had ground current and blown the internal 1 amp 600V fuse. Without continuity in the fuse there will be not output. It could also be a bad unit!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex Mppt issue

    Unit was replaced with another and same lack of performance ( read OP posts ), also, if the GFDI is blown the controller I believe the XW displays this information on the LCD, the unit put out energy according to the original post, about 1/10th that of an Outback unit

    There must be a language issue here as some very basic questions are not being answered, like how the unit is wired and the input and output LCD screens from the charger while operating

    Its either miss-wired or not configured correctly, two controllers doing the same thing when swap point to the installation, not the XW-Mppt. My bet its they have it wired as a common negative, which won't work on the XW as that would short out the internal shunts for input/output current measurement.
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Xantrex Mppt issue
    The XW-Mppt is a 4 wire Mptt controller. The Solar Panel leads must ONLY connect to the chargers "+" and "-" solar input, not anything else. Then the output of the chargers "+" and "-" go to the battery's

    Not connecting earth ground to the charger will have no effect on performance, it only for the US NEC electrical code for having ground fault protection on the array wiring

    Sounds like the controller is wired where the solar panels "-" is connected directly to the batterys "-", that will not work with XW-Mppt but will with the Outback unit

    That is too bad the XW60 was designed this way, although, if wired correctly, works great and is much cheaper to design than the "normal" method.
    The RVPP worked this way as well, but that's antiquated now.

    I say this mainly because it can (and will) confuse users ad installers because they are used to being able to use just one common negative wire, as with the C40 and MX60, etc.

    Take care,
    boB
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex Mppt issue

    The choice to use low-side measurement was it allowed a cost effective way to have precision current sensing on both the array and battery currents.

    This allowed a robust and functional dynamic mppt tracking by using the array current which is loop compenstated for battery side AC inverter ripple.

    To my knowledge its the only functional dynamic mppt tracker on the market that works in all load conditions ... I have yet to test another unit that doesn't mess up in some way due to this issue.

    boB, in your to be released charger, are you doing dual high side current sense?
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Xantrex Mppt issue

    There seem to be quite a few of these "cost effective" methods in the XW60... There are times I wished I had input and output current sense but I see now that it really isn't "necessary", but certainly see how it can be helpful sometimes. No input sense yet here. It's not cost effective. :D Maybe some day or revision. We're not 100% done yet though. ;)

    There are a few problems with the XW60 that I know of. We'll let you know about these sooner or later. But, hey, all products have "some" shortcomings, whether because of "cost effectiveness" or just plain lack of knowing or usually, its that darn series of compromises that are a part of all designs. ALL of them... Classic or XW or whatever. Hopefully the overall shortcomings and compromises are minimized these so the customer gets a great deal.

    boB (in beautiful Montana this week)
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Xantrex Mppt issue
    This allowed a robust and functional dynamic mppt tracking by using the array current which is loop compenstated for battery side AC inverter ripple.

    Are you saying that the XW60 uses the 120Hz inverter ripple to an advantage by letting it be part of a natural "sweep" in addition to the other dynamic tracking algorithm ?

    boB
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    Re: Xantrex Mppt issue

    Very interesting! I will add that the XWCC is very fast in responding to loads and does not overshoot like the Legacy CC I use to have. It appears to be adjusting the mppt every 3 seconds.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Xantrex Mppt issue
    Very interesting! I will add that the XWCC is very fast in responding to loads and does not overshoot like the Legacy CC I use to have.

    Now that is a very good thing ! SG can help to explain why that part works so well.

    boB (going into the big city today I think) :D
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex Mppt issue

    boB, the DSP control loop compensation can be tweaked so the even if there is 120 hz ripple on the battery side, the Array side is closer to DC values, making any type of Mppt more precise and less influenced by ripple.

    The current FM series stalls Mppt at high current with large inverter or GridTie loads as it attempts to track mppt using battery values ... its a threshold where the ripple is greater than the perturb value and tracking stalls ... all chargers I have done detailed testing on except the XW have this issue as they all use battery values for tracking

    overshoot is just poor control loop regulation, the XW uses a 100mhz TI DSP and is not math or algorithm bound, that's another reason for its good performance.

    I wasn't happen with some of the changes they made to my design but the end product is the still the best of the available chargers on the market today, no other charger out harvests the XW, even with the changes Xantrex made
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Xantrex Mppt issue
    boB, the DSP control loop compensation can be tweaked so the even if there is 120 hz ripple on the battery side, the Array side is closer to DC values, making any type of Mppt more precise and less influenced by ripple.

    So, are you saying that the XW60 is a current mode control design rather than Voltage control ?

    I've got one but didn't look quite that closely. I looked like it was sensing the negative input and output terminals directly, and not the inductor instantaneous current.

    Thanks,
    boB
  • Malasombra
    Malasombra Solar Expert Posts: 24
    Re: Xantrex Mppt issue

    Hi all again and sorry for the delay.

    Now the XW is under test in a warehouse corner and working/testing. The maintenance service tried it in a simulator founding nothing weird.
    I have checked the manual in different languages and now im even more puzzled :cry: than b4.
    The wiring is the same in both brands , from panels to mppt ,then accus. There´s not a negative wire from panels to batt directly. In fact i find "wired as a common negative" that Solar Uppy mention quite odd. Any schems would be great.

    I will keep you posted if any discovery and will try to decipher this thread ( not easy to follow you guys in your giberish :blush:)

    Thanks.
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    Re: Xantrex Mppt issue

    Describe the failure again exactly in the new location. Is it working there???? The previous suggestion was that you had the solar negative and the battery negative reversed! You could have bad charge controllers but 2 of them doing the same thing woud be rare. It is also hard to understand what you write. You are doing better than most of us if the situation were reversed.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • creakndale
    creakndale Solar Expert Posts: 27 ✭✭
    Re: Xantrex Mppt issue

    Malasombra,
    I purchased one of the very first Xantrex XW-MPPT60-150's to roll off the assembly line back in September 2007. The unit was defective upon receipt but Xantrex paid shipping both ways and fixed the defect. However, most of the time, the MPPT function does not operate properly.

    On a cloud free day, the MPPT has a decent chance of working all day. If a cloud goes by and the PV output current drops as expected, the MPPT can get confused and end up operating near the array's open circuit voltage (Voc). This results in much less current into the batteries. Most of the time it will not recover from this condition even after it "wakes up" the next day.

    The easiest way to clear the MPPT lockup is by going to the "Device Menu" and selecting "Standby" (or "Hybernate") and then back to "Operating".

    Since my MPPT mode is flawed, I use the "Input Menu" to force the Charge Controller into "Manual" mode with a "Reference" of ~75% of the array's Voc. This has worked flawlessly. I suggest you try operating in "Manual" for awhile if you haven't already tried it.

    Also, be aware that there was a Technical Bulletin issued for the XW-MPPT60-150 (976-0177-01-01 Rev A) for units manufactured from June to September 2007 dealing with a defect. See:
    http://www.xantrex.com/web/id/2331/docserve.aspx

    I was planning to send my XW unit back to Xantrex for MPPT repair when I saw the acquisition by Schneider Electric and decided to hold off until things settle down. Plus, shipping the unit to Canada is a pain.

    creakndale
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Xantrex Mppt issue
    The previous suggestion was that you had the solar negative and the battery negative reversed!

    WoW ! I hadn't thought of that possibility B4 ! Another good reason not to be quite so "cost effective". :D

    boB
  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Xantrex Mppt issue

    I would guess you have something simple going on either

    A- solar panel negative is hooked to the battery negative somewhere

    B- the negatives from solar panels and batterys are reversed

    I have no idea what the second scenario would do maybe when the sun comes up i will try it and post back.

    Xantrex did make there unit more "Cost Effective" then any of the other units i have tested. My gut says if you have a working Outback leave it in there it will most likely out perform the XW any how
  • Malasombra
    Malasombra Solar Expert Posts: 24
    Re: Xantrex Mppt issue

    Thank you all for your responses.

    One of the Xw is in his own workshop and running normal ,still in testing . The thing is that he had installed more than 30 Ob units without any problems and left using xantrex for god. I am pushing him to clarify why this hardware is not working as should be or what in hell is so special in its electronics.
    In here http://forum.solar-electric.com/showthread.php?p=29085#post29085 i asked for a buglist or firmware flaws (similar to outback) so i´ll pass the bulletin creakndale linked and check for more.
    Will try to get a picture from wiring, would be funny to find a misslabeled pole socket D´oh

    ( much easier is to practice english on the beach ,but.............)
  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Xantrex Mppt issue

    the XW installs completely different then the outback. it is very important that the solar panel negative lead go right to the XW it CAN NOT tie to the battery negative or ac Neutral or ground any where.

    This is confusing and really a pain in the but for us installers especially on larger systems
  • lorelec
    lorelec Solar Expert Posts: 200 ✭✭
    Re: Xantrex Mppt issue

    In defense of low-side sensing....I'm guessing that the main reason it was chosen for the XW controller was to simplify the design of the current sense circuitry. High-side sensing of higher voltage rails becomes problematic because the parts involved (typically op amps or instrumentation amps) need to rated to operate with that voltage (maybe 150v for the XW?)...and many aren't. There are ways around that, but the alternatives usually cost more and can involve more parts. Low-side sensing, while troublesome from an installation perspective, is simple, low-cost, and reliable. I don't use low-side sensing on my controller, but even so, I find that using separate ground wires for array and battery can help to quiet some of the ripple from particularly noisy MSW inverters, so I suggest in my manual that separate wires be used. Maybe it's magic or maybe it's my imagination...or maybe it's something more scientific involving the inductance of the wire or some kind of common-mode effect. I've never really looked into it.

    The "counterfeit component" issue with the XW is an interesting one. Anyone know exactly what component was involved?

    Marc
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    Re: Xantrex Mppt issue
    lorelec wrote: »
    The "counterfeit component" issue with the XW is an interesting one. Anyone know exactly what component was involved?

    Marc

    I read about it, and can't remember.... in the service notes at big X. You could search it. We use S level (space) parts at my other job and there are all kinds of weird things that can happen to components. Some of the "old guy's" here say they test and stress the components just long enough so they will function through the billing cycle!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Malasombra
    Malasombra Solar Expert Posts: 24
    Re: Xantrex Mppt issue

    Hi all
    A quick update.

    The unit under observation is now fully functional. After checking that the failure was on vertical position and not horizontally he proceed to open the electronics bay and a flat wire connector was not correctly inserted.
    With the seconds unit the thing will be more difficult to explain because .........it´s gone. A couple of days a go and after an emergency call from his customer at 7:00am (batt depleted again) changed it for an OB and threw the xw from the roof ( ballistic ).

    Keep you posted with news if any.

    Regards
  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Xantrex Mppt issue

    glad to hear you figured it out. and also good to know the Xw will take a trip off the roof in rage and still work. There has to be a commercial in there somewhere??
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Xantrex Mppt issue

    first there was timex and now there's xantrex as it seems they take a lickin and keep on tickin.:p
  • Malasombra
    Malasombra Solar Expert Posts: 24
    Re: Xantrex Mppt issue

    mmmmmmm
    Gone in this case means = dead. After the autopsy i will let you know the results .

    Regards
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Xantrex Mppt issue
    Malasombra wrote: »
    threw the xw from the roof ( ballistic ).

    Dare I ask why the XW was on the roof ? Hopefully, not installed there.

    I just can't imagine the labor involved to carry it up, just to throw it off.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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