Xantrex XW6048 - fault F49 - DC over voltage

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Comments

  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    In my earlier response about battery size, I forgot about the ripple current the AC sinewave inverter puts on the battery.  The ripple current from inverter sinewave power profile will put ripple current on battery at twice the AC line frequency rate.

    The net charge to battery may be zero due to PV charge controller supplied power but for high inverter output AC power push, the ripple current that is impressed on batteries can be quite large.

    With a solar charge controller tied to batteries, the PV output is mostly a smooth continuous PV illumination based current push to batteries and inverter DC input.  The batteries act as large filter capacitor to smooth the inverter's AC power profile ripple current.  

    This means the battery size must be large enough to take the large ripple current even though the average power taken from battery is zero.






  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    I think I understand now, is it sort of like water hammer is to plumbing, slamming of the water for a split second it bounce back and essentially the inverter it turning on and off starting and stopping that load from the batteries.  We need bigger capacitors  ;)  
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    edited September 2022 #124
    If your application is to primarily provide AC power supplementation with only occasional grid power outage you are better off to use PV grid tie battery-less inverter to supplement AC power.  Using an XW with DC coupled PV power puts a large continuous ripple current on batteries that will wear them out. 

    You could use an AC coupling arrangement, but I would probably keep GT inverter directly on grid mains most of time to avoid the issues with reverse power surge push into XW output when grid is down.  GT PV inverter power output control with frequency shifting by XW is slow reacting. 

    With no grid power, battery backup operation, during high PV production, if you switch off a large house load there is a sudden overproduction that must be sucked up by XW inverter until it does the frequency shifting, GT inverter recognizes it and backs down its production.  This can also happen when grid drops out eliminating ability for PV power grid push.  This can take up to a couple of seconds to correct during which the XW is getting hit with the large back surge current from PV GT inverter.

    There is no battery charge current regulation for AC coupling back surge, other than inverter shutting down for DC input voltage over high end limit.  Generated power always has to go somewhere.
  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    This is helpful in understanding all this.  Our situation is I wanted significant loads to be backed up essentially via solar, but our utility wants $20 a month of a PV meter and then $.02 per kWh credit back, that wasn't going to work so what I have now is to disconnect from the grid during on peak or high rate and re-connects during off peak or low rate.  I did consider leaving the XW connected to the grid (it is set to not sell back to the grid but the lowest input I could set was 1 amp. so it was drawing 240w all day. 
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • pcguy2u
    pcguy2u Solar Expert Posts: 151 ✭✭✭
    edited September 2022 #126
    Hey Brock, are you using a timer to make that determination?  I've been tinkering with this device to switch to the utility (could alternatively use a generator) to charge the batteries and/or remove the load on the batteries and to default to the batteries when they are up to the task.
    My transfer switch is a Generac 200amp and the whole house switches with the transfer switch.  My current bank of batteries is almost enough to do this off grid testing, but it is dependent on worst case factors.  Hence my looking into more batteries...
    For now, no permanent changes are contemplated until the dust settles with PG&E and their attempts to modify the solar environment instead of modifying their business model.

    Nick
  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    The funny thing is for 15 years we actually had a normally open lead from our meter, it would close for on peak and critical peak and stay open for holidays and weekends.  Our local utility got bought out and now, for some reason they say our meter can't control it anymore, go figure.  I have a plain old digital timer feeding the contactors, so holidays are a manual switch for us.  The only annoying part is if they schedule a critical peak during off peak times, I have to run home or have someone at home turn everything off, very annoying.  You would think they would have liked it the way it was before where they could hit a button and all kinds of loads shed from the grid...

    Even on a "busy" day with the kids home the most we have pulled is about 5 kWh of the 20 kWh bank so I am not as worried about a low battery disconnect, although then it would be more automated overall.
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,731 ✭✭✭✭✭✭
    edited September 2022 #128
    Brock said:
    What is an open loop charge/discharge?  I do have the xantrex set to only 25 amps charge if needed in the middle of the night.  Each 48v 100a battery has its own 100amp BMS so I really have 400 amps at 48 (54) volts with 800 amps surge, which I hope to never need.  Most of the time I am pulling under 1000w or about 20 amps from the bank or 5 amps per pack. 
    Open loop would be the XW or it's chargers not actively managing charge/ discharge from  BMS data. You will not get Soc data on the SCP or Insight devices out to the Cloud. The BMS in closed loop would actively monitor the xanbus network. You probably are fine with a 400AH bank.

     A 100AH bank could be damaged by XW in a big surge or charging from a large source if it were open loop.

     The homes below with the green 100  (in bat Soc) are closed loop systems that get Soc out to the cloud or your phone.



    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • t00ls
    t00ls Solar Expert Posts: 245 ✭✭✭
    I have the same problem...dc over voltage...on the xw4548 it is f63

    I found the problem to mine is the amperage sensor that detects how many amps are coming in from the batteries after the board with all the capacitors on it

    the thing in this picture on my post .....the solder connections are bad
    https://forum.solar-electric.com/discussion/comment/404751#Comment_404751

    this could be your problem