Sell voltage reading and Xantrex 6048

packrat
packrat Registered Users Posts: 7 ✭✭
in Grid Tie and Grid Interactive Systems #1
I have a 48 volt, 5.3KW, grid tie system with battery backup and I have my sell volts set to 52.8. The battery voltage shows 51.8. If I change my sell voltage the battery voltage is always 1 volt lower. I have checked with a meter and the display voltage is the same as the meter. Is this normal or is the Xantrex not setting sell voltage properly? Other than that it seams to be working right.
Thanks
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #2
    Re: Sell voltage reading and Xantrex 6048

    There are two or three places where you can get a disagreement (as I recall from reading posts here):
    1. Meter could have 0.5-1.0 volt error
    2. You can get a voltage drop from the battery to the inverter across your wiring
    3. I believe some of the Xantrex meter readings are temperature corrected back to 77 degrees F (i.e., if your batteries are hot or cold, the meter software will adjust reading back to standard battery temperature conditions).
    It is perfectly OK to adjust the sell voltage up a bit to account for errors in the system if you are satisfied your DMM is accurate and the system is operating well otherwise (repeatable meter readings with 1.0 volt difference for example).

    -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: Sell voltage reading and Xantrex 6048

    #3 is your cause ... the voltage shown are temperature corrected values.
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  • packrat
    packrat Registered Users Posts: 7 ✭✭
    #4
    Re: Sell voltage reading and Xantrex 6048

    Thanks for the replies to my question. If it is temperature corrected to 77 degrees,
    right now it says the battery temp. is 75 degrees and there is still a one degree between the sell volts and the battery volts. It is still one degree difference when it goes into sell mode in the morning when the battery is 57 degrees. Am I missing something?
    Tom
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  • grunt
    grunt Solar Expert Posts: 37 ✭✭
    #5
    Re: Sell voltage reading and Xantrex 6048

    There is a one watt voltage difference on mine too ( 6048 ). I have AGM sun extender batts and they really don't change temp at all but I still have the temp sensor hooked up. The basement on the other hand changes 20 degrees through out the year but as always my voltage is always one volt exactly lower then what I set it at so I set it one volt higher and all works out fine.
    I would not worry about it too much. Still I got to say I am curious too.:roll:
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