The Victron GX Tank 140 is an add-on for Victron GX devices that reads up to four tank level sensors. Its job is to handle the senders a Cerbo GX’s own resistive tank inputs can’t: industrial-style 4–20mA current senders and 0–10V voltage senders. Here’s what Victron’s product page and GX manuals say about it.
Victron GX Tank 140: Key Features
| Tank inputs | 4 |
| Sender types | Current (4 to 20mA) and voltage (0 to 10V) |
| Sender power | 2 inputs supply 24V to the sender; 2 need an external supply (power-in terminal with fused outputs provided) |
| Connection and power | USB to the GX device; no extra power wiring |
| Scale | Configurable upper and lower limits, e.g. a 0–5V sender |
| Damping | Adjustable, 1 to 60 seconds |
| Fault detection | Alarm when readings are out of range |
Source: Victron GX Tank 140 product page.
How It Fits a GX System
The GX Tank 140 plugs into a USB port on a Cerbo GX or another GX device and takes its power from there. The GX device then shows the tank levels on its display or a GX Touch, logs them to the VRM portal, and can send them over NMEA 2000 to a boat’s multifunction display (MFD). The Cerbo GX manual has a dedicated “Connecting a GX Tank 140” section.
GX Tank 140 vs the Cerbo’s Own Tank Inputs
The Cerbo GX has 4 resistive tank inputs, according to its technical specifications. Those suit the common resistive senders in many RVs and boats. Add the GX Tank 140 when your senders are 4–20mA or 0–10V types, or when you need more than four tanks.
Uses
- Fuel and water tanks on boats with industrial pressure senders.
- Off-grid water storage using a 4–20mA submersible level sensor.
- Generator fuel monitoring, combined with GX generator auto-start rules that can use tank levels.
Who It’s For
- Cerbo GX owners with non-resistive tank senders.
- Marine installs that want tank data on the MFD through NMEA 2000.
- Remote sites that need tank levels in VRM.
Good to Know Before You Buy
- Needs a GX device; it doesn’t work alone.
- Two of the four inputs need external sender power.
- Doesn’t read resistive senders, which are covered by the GX device’s own inputs.
Full specifications for the GX Tank 140 are on Victron’s product page.
How 4–20mA and 0–10V Senders Work
Both sender types turn a tank level into an electrical signal the GX Tank 140 can read.
- 4–20mA current senders send 4mA at the bottom of their range and 20mA at the top. Because the signal is a current, it holds up well over long cable runs, which is why many industrial pressure and submersible level sensors use it. Because an empty tank still reads 4mA, a reading well below that points to a wiring problem, and the GX Tank 140’s out-of-range alarm is there to catch it.
- 0–10V voltage senders output a voltage that rises with the level. Some cover only part of that span, such as 0–5V, which is what the GX Tank 140’s configurable upper and lower limits are for.
Worked Example: Scaling a 4–20mA Sender
Take a submersible sensor rated 4–20mA over 0–2m of water, in a tank that’s 1.6m deep. The sensor’s span is 16mA (20 − 4) over 2m, or 8mA per metre.
| Water depth | Signal (estimate) | Tank level |
|---|---|---|
| 0m | 4.0mA | 0% |
| 0.8m | 10.4mA | 50% |
| 1.6m (full) | 16.8mA | 100% |
Worked estimates from the sensor’s linear range. Use your sensor’s datasheet values.
So in this tank, 16.8mA is the reading to set as the upper limit, not 20mA. Otherwise a full tank would only read 80%.
Setup Steps
- Mount and wire the senders following the sensor maker’s instructions.
- Pick the input for each sender. Use the two inputs with the built-in 24V supply for senders that need power. For the other two, power the senders from the power-in terminal and its fused outputs.
- Plug the GX Tank 140 into a USB port on the Cerbo GX or other GX device. It’s powered from that port.
- Find each tank in the GX Device list, then choose the fluid type, volume unit and capacity.
- Set the upper and lower limits to match the sender’s real output at empty and full, as in the example above.
- Set damping between 1 and 60 seconds. A longer time steadies readings in tanks that slosh, such as on a boat underway.
- Check VRM and NMEA 2000 if you want tank levels on the VRM portal or a marine MFD.
Other Ways to Add Tanks to a GX
The GX Tank 140 is one of several options Victron’s GX manual covers:
| Option | Best for |
|---|---|
| Built-in Cerbo GX tank inputs | Resistive senders (European 0–180 Ohm, US 240–30 Ohm, or custom) |
| GX Tank 140 | 4–20mA and 0–10V senders |
| Mopeka Bluetooth sensors | Ultrasonic level sensing with no wires through the tank, including LPG |
| NMEA 2000 tank senders | Boats that already have an NMEA 2000 backbone |
| A second GX device on VE.Can | More resistive tank inputs |
For tanks with odd shapes, the GX device lets you set a custom tank shape with up to 10 points, so a half-height reading can map to the right share of volume.
FAQ
Does the Victron GX Tank 140 need its own power supply?
No. It’s powered over USB from the GX device. Only two of the sender inputs need an external sender supply.
Can I see tank levels remotely?
Yes, through VRM, as long as the GX device is online.
What’s the difference between a 4–20mA and a resistive sender?
A resistive sender changes resistance with the level and reads on the Cerbo GX’s own tank inputs. A 4–20mA sender outputs a current and needs the GX Tank 140.
Do I need all four inputs?
No. Connect only the tanks you have and leave the unused inputs disabled in the GX settings.
Will tank levels show on my chartplotter?
Yes. The GX device can send tank data over NMEA 2000 to compatible MFDs.
Why does my reading jump around?
Liquid moving in the tank changes the sender’s output. Raise the damping time, up to 60 seconds, for a steadier reading.
Sources: Victron GX Tank 140 product page; Cerbo GX manual (technical specifications, connecting a GX Tank 140, generator auto start/stop), victronenergy.com, accessed Oct 2026.
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