Tank monitoring with Victron GX Tank 140, accuracy matters

Ben Stein

Ben Stein

Publisher of Panbo.com, passionate marine electronics enthusiast, 100-ton USCG master.

4 Responses

  1. Ben Ellison Ben Ellison says:

    My boat already has (Wema) resistive tank senders and last winter I wired them to the Victron Cerbo with mainly good results. Setting up the tanks and custom calibrating them (if necessary) look very similar to your Venus screens. You can also custom name tanks — so there’s no confusion about Port and Starboard fuel tanks on Gizmo — and all four of my tanks show up properly on NMEA 2000 displays.

    Overall, I think that this bonus Cerbo feature is as configurable as the CZone module I used with the same senders almost 10 years ago, except that no PC or gateway is needed. https://panbo.com/bep-czone-signal-interface-a-nmea-2000-winner/

    But note the qualified “mainly good results.” Last week I put 50 gallons of diesel into the nearly empty 140 gallon starboard tank and Cerbo deemed it 66% full! I’m guessing that this is a sender problem, as the port fuel and water tank levels have made sense so far (and sometimes the black water tank too, especially if Gizmo slams hard enough on someone’s wake).

    At any rate, while it’s neat that Victron is even putting the tank levels on my sharable VRM site — https://vrm.victronenergy.com/installation/105905/share/ea38a0bd — at least two are quite inaccurate, though not their fault. So I’m back to sticking tanks and maybe custom calibration.

  2. Anonymous says:

    my boat has ultrasonic transducers on fuel tanks (2), and water tank, that read 0-5V ,
    (likewise the cerbo doesnt support voltage sensors,) hence fitted a tank 140,
    in parallel with the BEP display – very happy with tank 140 capabilities to extend the cerbo inputs.
    now planning a submersible pressure transducer for black tank.. on the fourth input.

    ..i recall i had some nmea2000 confusion … watch out for the N2K instances produced by cerbo , i recall they are counter intuitive to the tank140 input numbering

  3. Butch Davi says:

    Very interesting, Ben.

    When we were RVing we mostly stayed in campgrounds with full hookups or at least water and sewer hookups. We simply left the gray water drain open until our last night on the site, when we closed the valve. This was to allow a few gallons of gray water to accumulate for the following day. Just before leaving we opened the black water tank and drained the sewage. When the black water had fully drained we closed the valve and opened the gray water tank drain valve to allow the gray water to rinse the drain valves and sewer hook up. Many (most) RVs were equipped with a black tank water hose attachment which was used to rinse the black water before closing the valve and opening the gray water valve.

    Some RVers made the mistake of leaving the black water drain open full time whenever they had sewer hookups. That very serious mistake often led to the dreaded brown mountain in the tank. Although we never had the problem we were paranoid and poured a bag of ice through the commode immediately before driving off to provide some scrubbing action if the black tank bottom.

  4. Peter Alexon says:

    How did you wire the sensor to the Tank 140? Any wiring diagram?

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