XW 6048 and Grid Support Voltage

Philip C
Philip C Solar Expert Posts: 45 ✭
in Grid Tie and Grid Interactive Systems #1
I'm having a hard time getting a particular unit to sell back to the grid when I set the Grid Support voltage above the bulk voltage.

Current Settings
6048 Charge Cycle "2StageNoFloat"
XW MPPT 60 CC Charge Cycle "3Stage"
Battery Type "AGM"
When Grid Support Voltage set to 58.2, does not sell
But when Grid Support Voltage set to 53, sells back to grid.


The system is a 5.8kW STC PV, 224AH 48V AGM, two XW MPPT 60 Charge Controllers, and one XW 6048 Inverter.

Any Help would be greatly appreciated.

Thanks,
Philip
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #2
    Re: XW 6048 and Grid Support Voltage

    Why do you want to set the sell voltage to 58 volts?

    Normally, you set the sell voltage to the batteries "float" voltage.

    The XW, as I understand it, will automatically set itself to the bulk and absorb charging voltage if it determines that the battery has been discharged for a significant amount of time--and after the battery bank has been recharged (bulk, absorb), the XW inverter will go back to the sell voltage (float)--Which is where you want the bank voltage to be for the long term.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #3
    Re: XW 6048 and Grid Support Voltage

    For best performance, you want the sell voltage to be just above a full battery voltage, typically 12.7V * 4 = 50.8V @ 77F/25C is full charge.

    I run mine @52-53 volts, the lower voltage if i'm selling at close to the 6kw rating of the XW is required for proper operation ... WHERE IS CREWZER
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  • Philip C
    Philip C Solar Expert Posts: 45 ✭
    #4
    Re: XW 6048 and Grid Support Voltage

    I agree in most cases you want to set the sell voltage to slightly below the float voltage. But supposedly the XW inverter and XW CC will communicate with each other and more efficiently sell back to the grid when sell voltage is set above the bulk voltage. So this is only true when using both products in communication with each other.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #5
    Re: XW 6048 and Grid Support Voltage

    Basically, the MPPT Charge controller is trying like crazy to charge the battery bank to 58 volts, and the XW Inverter is taking all of the energy that the charge controller is inputting "to the battery" and attempting to hold the voltage down to 52-53 volts--Thus is the inverter that is "regulating" the battery voltage/charging during Grid Tied operations.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #6
    Re: XW 6048 and Grid Support Voltage

    Not true, I was part of the XW design team FYI

    Anything above float and the support the inverter and chargers require from the batterys to act as a buffer is gone. Your own test show the results.

    The XW do communicate via Xanbus, but trying to run batteryless isn't one of the features, which when running at 58V is basically what you are doing as none of the enegry is going into the batterys.
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  • Philip C
    Philip C Solar Expert Posts: 45 ✭
    #7
    Re: XW 6048 and Grid Support Voltage

    This is good to know, thanks for your help.

    Another XW question for you, on the CC there is a Tracking Auto Reference voltage setting. Where do you want to set this? At Vmp or do you want to adjust for temps?
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #8
    Re: XW 6048 and Grid Support Voltage

    No, that's if you want to disable the Mppt tracking and run with a fixed voltage, out of the box, the XW-Mppt should need no setting changed for your setup
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