Victron Cerbo Tank Sensor Guide: Mopeka, Ruuvi, GX Tank

A Victron Cerbo tank sensor setup can show fresh water, waste, fuel and propane levels next to your battery data, both on the GX screen and remotely in VRM. There are three ways to connect sensors: wired resistive senders, the GX Tank 140 for current and voltage senders, and Bluetooth sensors like Mopeka and Ruuvi. Here’s how each one works, based on Victron’s Cerbo GX manual and the GX Tank 140 product page.

Electrical work can be dangerous: follow the manual, fuse and size every cable correctly, and use a licensed electrician for anything connected to household wiring.

A Cerbo GX tank sensor video.

Victron Cerbo Tank Sensor Options

Option	Connects via	Best for
Built-in tank inputs	4 resistive inputs on the Cerbo	Standard resistive senders
GX Tank 140	USB (also powers it)	4-20mA and 0-10V senders
Mopeka	Bluetooth LE	Propane and other tanks, no drilling
Ruuvi	Bluetooth	Temperature, humidity, pressure
Wired temperature sensors	4 temperature inputs	Battery or compartment temperature

Sources: Victron Cerbo GX manual; GX Tank 140 product page.

Built-In Resistive Inputs

The Cerbo GX MK2 and MK3 have four resistive tank level inputs and four temperature sense inputs. These suit the common resistive senders found in many RVs and boats. You set the sender type and the tank’s fluid type in the GX menu.

GX Tank 140

The GX Tank 140 reads up to four tank sensors and accepts 4-20mA current senders as well as 0-10V voltage senders. It connects and is powered over USB. Two of its inputs supply 24V to power the sender. The other two need an external supply, and the unit has a power-in terminal with fused outputs for that. You can set upper and lower limits for senders that use only part of the scale, and damping from 1 to 60 seconds. It raises an alarm if a sensor reads out of range.

Mopeka Bluetooth Tank Sensors

Mopeka sensors measure liquid level ultrasonically through the tank wall, in both pressurized and unpressurized tanks. Depending on the model, they mount on the top or bottom. They send the level, temperature and their own battery voltage to the GX over Bluetooth Low Energy.

Ruuvi Temperature Sensors

Ruuvi tags send temperature, humidity and air pressure to the GX over Bluetooth. They work well for fridges, battery compartments and cabins.

Fixing Weak Bluetooth

Victron says that even GX devices with built-in Bluetooth can get better range from a USB Bluetooth adapter. Mount the Cerbo away from metal enclosures, and see the manual’s list of compatible adapters.

On Boats: Send Levels to Your MFD

A GX device can put tank levels on the NMEA 2000 network so a chartplotter can display them.

Victron lists every GX Tank 140 variant, with datasheets, on its official product page.

Worked Example: An RV With Three Tanks

A travel trailer with a Cerbo GX, a resistive fresh-water sender, a resistive grey-water sender and a 20lb propane bottle:

The fresh and grey senders wire into two of the Cerbo’s four resistive tank inputs.
In the GX menu, set each input’s fluid type and sender standard, then calibrate the empty and full readings.
A Mopeka sensor sits under the propane bottle and reports its level over Bluetooth, with no drilling or plumbing.
A Ruuvi tag in the fridge reports temperature, so the GX overview shows water, propane and fridge status beside battery state of charge.

Worked Example: A Boat With Industrial Senders

A motor yacht with two diesel tanks fitted with 4–20mA senders and a fresh-water tank with a 0–10V sender:

The GX Tank 140 connects to the Cerbo GX over USB, which also powers it.
The two diesel senders use the inputs that supply 24V, so they need no extra wiring for power.
The fresh-water sender uses a third input, powered through the unit’s power-in terminal and fused outputs.
Damping smooths readings when the boat rolls, set anywhere from 1 to 60 seconds.
The GX sends all three levels to the chartplotter over NMEA 2000.

Calibrating a Tank

Open the tank’s settings on the GX device.
Choose the fluid type, such as fresh water, waste water, fuel or LPG.
Set the tank capacity so the GX can show volume as well as a percentage.
With a resistive sender, choose the sender standard or enter its empty and full resistance.
With the GX Tank 140, set the upper and lower limits if the sender uses only part of its range.
Fill or empty the tank and check the reading matches.

Setting Alarms

Each tank can trigger low or high level alarms on the GX. A fresh-water low alarm at 15% or a waste-water high alarm at 85% helps you plan a refill or dump stop before it’s urgent (example settings). Alarms also appear in VRM, so you can get notified away from the vehicle.

Choosing the Right Sensor

Tank or need	Good fit
—	—
Factory resistive senders in an RV or boat	Built-in Cerbo tank inputs
4–20mA or 0–10V industrial senders	GX Tank 140
Propane bottle or tank, no drilling	Mopeka Bluetooth sensor
Fridge, cabin or battery compartment temperature	Ruuvi tag
Battery temperature, wired	Cerbo temperature inputs

Bluetooth Range Tips

Keep the Cerbo GX out of fully metal cabinets where possible.
Add a compatible USB Bluetooth adapter and position it where it has a clearer path to the sensors.
Check sensor battery voltage on the GX now and then, since Mopeka and Ruuvi sensors run on their own batteries.

Using Tank Data Day to Day

Once tanks show on the GX, the Overview page puts water, waste and propane next to battery state of charge. In VRM, tank history shows how fast you use fresh water per day, which makes it easier to plan how long you can stay off-grid before a refill (example use).

FAQ

Does the Cerbo GX need a GX Tank 140 for tank sensors?

Only for 4-20mA or 0-10V senders. Resistive senders connect directly to the Cerbo.

Can I see tank levels remotely?

Yes. Levels are logged to the VRM Portal.

How many tanks can a Cerbo GX show?

The Cerbo has four resistive inputs, and each GX Tank 140 adds up to four more. Bluetooth sensors add to that.

Can I see propane level from my phone?

Yes. With a Mopeka sensor on the GX, the level shows in VRM and Remote Console.

Does a Ruuvi tag measure tank level?

No. Ruuvi tags measure temperature, humidity and air pressure.

Sources: Victron Cerbo GX manual (Technical specifications; Connecting supported non-Victron products); GX Tank 140 product page; victronenergy.com, accessed Oct 2026.