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Smartshunt reading not the same as camper panel (Voltages)

StilleyStilley Member Posts: 13
in Battery/Electrical & Solar
Hey there, I cross posted this on the Tab Owners Facebook page just as a heads up

Wondering why we might be getting a different voltage reading on our smartshunt in the Victron app compared to our panel that’s located inside our camper. Our app is saying our voltage is at 12.19 while the panel is 10.8 obviously not ideal but we’ve been just going off of the app so were a bit unaware.
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  • Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,952
    we need a little more information.  Is it a new shunt?  What model and year TaB?

    The monitor panels are not as accurate as a shunt, assuming the shunt is set up correctly.
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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  • StilleyStilley Member Posts: 13
    Sharon_is_SAM said:
    we need a little more information.  Is it a new shunt?  What model and year TaB?

    The monitor panels are not as accurate as a shunt, assuming the shunt is set up correctly.
    I am so sorry! This is a new 2025 TAB 360 

     Does this look right besides the fact that it was installed upside down haha 
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  • elbolilloelbolillo Member Posts: 512
    And what type of monitor panel is installed inside?
    _____________________________________________________
    Ken / 2023 Tab 400 “La Bolita” (29,000+ miles) / 2024 Toyota Sequoia
    2025 - 1 Trip - 25 nights - 2 National Parks
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  • Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,952
    I think there should only be 1 lead on the “to battery” shunt terminal.  
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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  • HoriganHorigan Member Posts: 757
    There are other posts here about new trailers being mis-wired at the shunt. Only the negative wire from the battery should go to the battery side of the shunt. 
    Rich
    2019 T@b 400
    2013 Toyota Highlander 3.5L V6
    Bellingham WA
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  • StilleyStilley Member Posts: 13
    Horigan said:
    There are other posts here about new trailers being mis-wired at the shunt. Only the negative wire from the battery should go to the battery side of the shunt. 
    Ahh, I didn’t know that this would affect the reading but it’s obvious that it would right? Haha. I have very basic knowledge on batteries, but if this were the case and it has the extra wire (which it does) would it be reading too high after all? 
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  • StilleyStilley Member Posts: 13
    Sharon_is_SAM said:
    I think there should only be 1 lead on the “to battery” shunt terminal.  
    That is also what I’m gathering, I found another post on this. Could this be affecting the voltage reading on the app, If so, how exactly? Sorry minimal knowledge on this!
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  • BaylissBayliss Member Posts: 1,421
    @Stilley, as @Sharon_is_SAM noted, there should only be ONE wire between the shunt post labeled "TO BATTERY MINUS" and the negative terminal of your battery.

    Therefore, remove the second wire (the one that runs between the "TO BATTERY MINUS" Shunt post and the battery negative ("-") side of the blue MPPT Solar Controller) from that shunt post and move it to the shunt post that is labeled "TO SYSTEM MINUS."  Assuming everything else is connected correctly, that should resolve the issue.

    I am a more visual person, so I am including a diagram of how my electrical system is connected for reference only.  In  the diagram, my Shunt is depicted in the right-center area of the diagram.  Your specific setup is different than mine, but if you follow the lines for the connections, you will see what I have described above.

    **********

    IMPORTANT:  Since you stated that you are not fully familiar with electrical work, for safety's sake I would recommend that before you move any wire(s), disconnect the wires attached to the 12V battery posts before doing anything with the Shunt connections.

    TIP:  Whenever you remove/reattach 12V battery wires, remember this simple rule:  "Negative OFF first, ON last."  As you can see in the second photo below, I wrote that rule on the negative ("-") battery wire on my trailer so I don't forget.

    In other words:

    When removing the battery wires - - disconnect the negative ("-") first, then disconnect the positive ("+") cable.

    When connecting the battery wires - - connect the negative ("-") side first, then connect the positive ("+") side.

    AND, whenever holding a wrench/socket wrench to add/remove the battery wires, make sure you do not accidentally allow the metal tool to touch both the "+" and "-" battery posts at the same time, or very bad things will happen!

    Good luck!!

    P.S.  Add a description of the year and model of your trailer to your signature line.  It will help forum members a great deal to have that information available.  You can take a look at my signature line, or those for other members, for examples of the type of information that is helpful









    2019 T@B 320 S Boondock Lite; 2025 Toyota Tundra CrewMax 4x4
    (Alde: 3020; Refrig: Isotherm Cruise 65 Eleg; Battery: BB 100Ah LiFePO4; Solar: Renogy 220W Portable Suitcase; Victron BMV-712; Pwr Cntr: PD-4135KW2B; EMS: PI-HW30C)
    Greg & Marlene (Tucson, AZ)


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  • pthomas745pthomas745 Administrator, Moderator Posts: 4,219
    This is the thread about the incorrect shunt wiring from the Factory.  Posted back in May.

    2017 Outback
    Towed by 2014 Touareg TDi
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