MT50 and Battery Monitor help

tjw721
tjw721 Registered Users Posts: 2 ✭
in Solar Beginners Corner #1
Hello! I am brand new to all of this and want to see if you guys can help with these. 

I am fairly confident in the readings for the MT50, but want to make sure that with nothing being plugged directly into the load that the .01A is correct.


As for the battery monitor... this one is completely confusing. I don't know how to read any of these numbers, at the time of the picture the voltage didn't match. Any help to understand would these be amazing!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    I am not sure what the external/internal resistance readings/settings are... Do you have a link to the battery monitor Manual?

    If you have nothing connected to the charge controller LVD output--It is possible that 0.1 Amps is within the margin of error (i.e., 0.0 +/- a couple of digits).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • fratermus
    fratermus Registered Users Posts: 48 ✭✭
    #3
    Note:  the face and battery icons on the MT50 are best ignored.
    2017 Promaster 159" offgrid campervan
    750w:100Ah LFP
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  • tjw721
    tjw721 Registered Users Posts: 2 ✭
    #4
    BB. said:
    I am not sure what the external/internal resistance readings/settings are... Do you have a link to the battery monitor Manual?

    If you have nothing connected to the charge controller LVD output--It is possible that 0.1 Amps is within the margin of error (i.e., 0.0 +/- a couple of digits).

    -Bill
    Bill- it was purchased on Amazon with a manual but it was washed in the laundry by mistake. I can't seem to make sense of it. I need to set the numbers but also understand what I'm looking at. Here is a picture from the Amazon listing. 
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    I am guessing this is the power meter:

    https://www.amazon.com/Multimeter-DROK-Consumption-Resistance-Voltmeter/dp/B07YBVHBGV

    and the manual:

    https://images-na.ssl-images-amazon.com/images/I/81SNPg5M-NL.pdf

    The external resistance is simply the Battery Bus current / Load current = Load Resistance.

    The internal resistance seems to be the (Battery Resting voltage - Battery Voltage under load)/Load Current = Battery "apparent resistance".

    The battery AH capacity is an estimate over time.

    The rest seem to be load based numbers:
    • Voltage = current battery bus voltage
    • Current = present load current (10 amps maximum--Not a "high current/high power" meter
    • Power = Present Battery bus voltage * Load Current = Power in Watts
    • Running Time = is the number of Hours:Minutes (since reset) that the load has been drawing current (does not count if current = 0.0 amps)
    • Energy = Cumulative Volts * Current * Time (hours) * 1/1,000 = xxx kWatt hours (1 kWH = 1,000 WH) "energy used by load" since last reset
    -Bill


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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