Nucleo GX vs Cerbo GX: Which Victron GX Device Fits Your System

The new Nucleo GX from Victron Energy is a good fit for a VE. Direct only system with no VE.Bus inverter/charger. It costs a few bucks less per unit and runs on a faster quad core processor than the Cerbo GX MK2. Whether that savings holds up once you add accessories depends on two things: your need for GX relays and I/O inputs (digital/tank/temp). This article will walk you through both options before you order either device.

Most buyers default to the Cerbo GX simply because it’s the name they know. But the Cerbo's real advantages, onboard relays and resistive tank inputs, only pay off if your hardware actually uses them. If it doesn’t, you’re paying for I/O you will never touch. The three questions below will make the right choice obvious.

1. Do You Have a VE.Bus Inverter/Charger, or only VE.Direct Components?

If your system does not have a MultiPlus, Quattro, or other VE.Bus inverter/chargers, the Nucleo GX gives you full GX functionality for less money and more processing headroom. The Nucleo connects up to 25 devices over VE.Direct and USB, plus more over VE.Can, which covers systems built around MPPT solar chargers, SmartShunts,small inverters, and a Multi RS, as they do not operate with VE.Bus protocol.

If VE.Bus is part of your current system or planned for later, start with the Cerbo since the VE.Bus is already built in. You’ll find that if you add one to a Nucleo GX system,you’ll need to buy a MK3-USB interface just to get a connection the Cerbo already has. 

2. Do you use the Auto Generator start/stop function?

A 2-wire start generator, where a single maintained contact closes to start and opens to stop, runs natively on the Cerbo GX's onboard relay. No extra hardware is required. Connect that same generator to a Nucleo GX and you’ll need a GX I/O Extender 150 just to generate the relay contact the Cerbo already has, which removes the Nucleo's lower price advantage.

A 3-wire start generator requires even more products. Onan, Generac, Kohler, and units commonly need separate start, stop, and run-sense wiring, not a single maintained contact. Neither GX device outputs that natively. Both the Cerbo and the Nucleo need an Elevation AGS module, or similar device, to convert the relay signal into the pulse sequence the genset expects. Once that module is in the build, regardless of which device you started with, the Cerbo's built-in relay stops being an advantage. The only remaining question is whether you already have a Cerbo to supply that first relay signal, or need a GX I/O Extender 150 to get one from the Nucleo.

3. Is Your Tank Resistive, or Voltage/Current Based?

The Cerbo GX includes four resistive tank inputs onboard. If your tank senders are resistive (ohm based), the Cerbo reads them directly with no extra accessory. The Nucleo GX has no tank inputs at all, and resistive senders are not what the GX Tank 140 accessory is built to read in the first place.

If your tank senders output current or voltage, the Cerbo's onboard resistive inputs cannot read them. A GX Tank 140 is required regardless of which device you choose. That means the Cerbo's tank advantage only applies to resistive senders. Once senders are voltage or current based, both devices need the same accessory, and the Nucleo's lower price stands on its own.

Which One Should You Order?

1. Does your system include a VE.Bus inverter/charger?

If yes, start with the Cerbo GX.

2. If VE.Direct only, does your generator need a 2-wire start?

If yes, the Cerbo GX wins on cost and simplicity.

3. Is your system simple, with no need for inverters/chargers or tank inputs?

The Nucleo GX wins in this set-up, given that you do not want an onboard touch screen.

Ready to order? Shop the Nucleo GX or Shop the Cerbo GX MK2.

Still not sure? Talk to our helpful team. We'll walk through your generator and tank sender specs to make sure you order the right gear the first time. 

Frequently Asked Questions

Is the Nucleo GX cheaper than the Cerbo GX?

Yes, at published retail pricing. The Nucleo GX lists around $266, and the Cerbo GX MK2 lists around $273.That gap can shrink once accessories like the GX I/O Extender 150 or GX Tank 140 are added to match a specific generator or tank sender type. Confirm current pricing before ordering, since retail prices change.

Can the Nucleo GX run generator autostart? 

Yes, but it needs a GX I/O Extender 150 to supply the relay signal, since the Nucleo has no onboard relay. The Cerbo GX has this relay built in.

Do I need an Elevation AGS module with a Cerbo GX? 

Only if the generator needs a 3-wire start. A 2-wire genset runs on the Cerbo's onboard relay alone, no Elevation AGS required.

Does the Cerbo GX support 4-20 mA or 0-10 V tank senders? 

 No. The Cerbo's onboard tank inputs are resistive only. Voltage or current based senders need a GX Tank 140 on either device.

Does the Nucleo GX have a touchscreen option like the Cerbo?

No. The Nucleo has no HDMI port. Local display is handled through an Android GX WiFi Display instead of a wired touchscreen panel.

Is the Nucleo GX good for marine use? 

It can work on a boat, but it was built primarily for ESS and off-grid installations around the Multi RS. Systems needing VE.Bus, tank, or relay functions out of the box are usually better served by the Cerbo GX.