shunt wire

ws9876
ws9876 Solar Expert Posts: 448 ✭✭✭
in Off Grid Solar & Battery Systems #1
why are some diagrams of shunt wiring showing a small pos battery wire going to the meter and others only breaking the neg battery wire..?
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
    Maybe the small pos wire powers the meter, and "breaking the neg battery wire" measures the current?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,615 admin
    #3
    The shunts are generally connected to the negative battery cable (you want to bus at "ground potential" to make sure that the shunt to meter wires cannot carry any short circuit current/catch fire in a short).

    The positive wire to the meter is for electronic meters that need DC power (power the LCD/LED display, run the "computer" if present to keep track of AH/WH/etc.). Can also be used by meter to monitor Battery Voltage (Watt calculations, battery condition).

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