Cerbo GX vs Cerbo GX MK2 — the marine system controller compared

If you're building a Victron-based 48 V boat system, the Cerbo GX is the single device that pulls everything together. It is not, on its own, a charger or an inverter or a battery monitor — it's the orchestrator that lets the chargers, inverters, MPPTs, BMSs, and shunts behave as one coordinated system. Without it, each device would run independently, voltages drift, the BMS's charge-current limit is ignored by half the chargers, and the helm has no single screen showing what the electrical system is doing.

Victron released the original Cerbo GX in 2019 and the upgraded Cerbo GX MK2 in 2024. Both run the same Venus OS firmware, both connect to the same VRM Portal for remote monitoring, and both are pin- and screw-compatible with the same enclosure footprint. The differences are real but mostly about networking, processor headroom, and a handful of port changes — not about what the device fundamentally does.

This guide walks through what the Cerbo does in a marine install, what changed in the MK2, and which one is right for a new build or refit. If you've landed here because you're configuring a multi-unit Victron array and just need the Cerbo step, see Configuring a three-phase Victron charger array.

→ The configurator outputs the loads and battery sizing that the Cerbo will end up coordinating →

What the Cerbo GX actually does

In a typical marine install, the Cerbo simultaneously talks to:

• The inverter/charger array over VE.Bus (one to six MultiPlus-II / Quattro units, single-phase or three-phase)
• MPPT solar controllers over VE.Direct or VE.Can (one per array, up to a dozen)
• The BMS over VE.Can / BMS-Can (Lynx Smart BMS, REC, Batrium, BYD, Pylontech, etc.)
• Battery shunts (BMV-712, SmartShunt) over VE.Direct
• DC-DC chargers (Orion XS, Orion-Tr Smart) over VE.Direct
• Tank sensors (water, fuel, holding) on dedicated tank-input pins
• Temperature sensors on dedicated temp-input pins
• Relays (two open-collector outputs) for generator start, AC contactor, etc.
• Digital inputs for things like bilge-pump tally, door switches, alarms

Out the other side, the Cerbo:

• Renders a touchscreen UI on a GX Touch 50 / 70 / 70 v2 connected via HDMI
• Serves a local web console on its Ethernet IP (full UI in a browser)
• Publishes telemetry to VRM Portal over the internet (cellular, WiFi, or Ethernet)
• Exposes Modbus TCP to MFDs, third-party tools, and Node-RED flows
• Publishes MQTT for home-automation systems and custom integrations
• Hosts Node-RED and Signal K (optional, on-device)

That central role is what makes DVCC (Distributed Voltage and Current Control) possible. Without a GX-class device, you can run a single charger and a single battery shunt — but you cannot have multiple chargers respect a single BMS-published charge-current limit, because there's nothing to arbitrate. The moment you have an inverter array and MPPTs and a CAN-bus BMS, a Cerbo becomes mandatory.

Cerbo GX (original) — hardware overview

The original Cerbo GX shipped in late 2019 as the successor to the Color Control GX and Venus GX. It's a small black plastic module, about 145 × 90 × 27 mm, with a wide DC input and a generous port count.

Ports and I/O

The rich port count is what makes the original Cerbo so useful in a complex install. A 50 ft cruising sailboat with three MPPTs, a SmartShunt, a Lynx Smart BMS, an Orion DC-DC, and a GX Touch can fill every port and still have headroom.

Processor and storage

By 2024 standards this is modest, and it shows. Venus OS runs cleanly, but loading the local web UI on a phone takes a beat, Node-RED flows with more than a few dozen nodes feel sluggish, and live VRM dashboards can lag behind the device by 10–15 seconds when the network is slow.

Power

A Cerbo wired to a flooded engine-start battery will eventually flatten it during winter lay-up. Wire it to the 48 V propulsion pack via a 48→12 V DC-DC and the BMS will keep it alive.

Cerbo GX MK2 — what changed

Victron launched the Cerbo GX MK2 at METSTRADE 2024 as a refresh, not a redesign. Same enclosure footprint, same screw spacing, same Venus OS firmware, same VRM features. The differences are inside the box.

Headline changes

1. Native WiFi 5 (802.11ac, 2.4 + 5 GHz). The original Cerbo's later production runs had built-in WiFi, but it was a single-band 2.4 GHz module. MK2 supports both bands and modern security (WPA2 / WPA3). Range and reliability on a steel-hulled boat are noticeably better.
2. Native Bluetooth. The original had no Bluetooth at all — VictronConnect would only see a Cerbo via the local network. MK2 lets you commission directly from a phone over Bluetooth, the same way you'd talk to a SmartShunt.
3. Faster CPU. A quad-core ARM Cortex-A53 replaces the original's single-core A7. The web UI loads visibly faster, Node-RED feels responsive, and Venus OS can run more concurrent services without thermal throttling.
4. More RAM. 1 GB DDR4 versus 256 MB DDR3. This is what unblocks Node-RED, Signal K integrations, and concurrent VRM streaming.
5. USB-C added. A single USB-C port replaces one of the USB-A ports. Useful for laptop-to-Cerbo direct serial debug and for the new generation of GSM modems that ship with USB-C.
6. Slight port reorganisation. VE.Direct port count is reduced (commonly to 3) but the freed real estate is used for the USB-C and improved heat-dissipation. For installs that genuinely need 4+ VE.Direct devices, a VE.Direct-to-USB converter or VE.Can-equipped MPPT addresses the gap — and most installs don't actually use all four.
7. Improved internal antenna design. WiFi and Bluetooth use a redesigned antenna, with significantly better performance behind a metal bulkhead.

What did NOT change

• VE.Bus, VE.Can, BMS-Can, Ethernet, HDMI, tank/temp/digital input counts and pinouts.
• DC input voltage range and idle consumption (still 8–70 V, ~3 W).
• Enclosure size and screw pattern — the MK2 drops into an existing Cerbo cutout without rework.
• Venus OS firmware — both run the same builds. Once Victron drops support for ARMv7 (the original's architecture), the MK2 will inherit the future feature set on its own.
• VRM Portal account and device pairing — you can swap a Cerbo for a Cerbo MK2 on the same boat and reuse the existing VRM site without losing history.

Side-by-side comparison

The MK2 commands a roughly €50 premium over the original at the time of writing. Both are still in the catalogue — Victron has not announced an end-of-life date for the original Cerbo, and Venus OS will continue to run on it.

Which one to spec — by use case

New build or full refit — MK2

For any 2026+ install you're starting from scratch, default to the MK2. The price difference is marginal against a €30 000+ electric refit, the WiFi 5 + Bluetooth combo simplifies commissioning meaningfully, and the headroom on CPU and RAM is the right side of futureproofing as Venus OS gains more on-device services (Node-RED, Signal K, MQTT-heavy integrations).

Replacing a failed original Cerbo — MK2

The drop-in replacement story makes this trivial. Same cutout, same screws, same VE.Bus / VE.Can / VE.Direct cabling. Pair the new device to the existing VRM site (Settings → VRM Online Portal → use the same site ID) and history is preserved.

Working install you're not changing — stay on the original

The original Cerbo isn't going anywhere. If your boat has one, it's running Venus OS, it's talking to VRM, and you're not running into headroom problems — there's no compelling reason to swap it. Use the €330 elsewhere.

Installs with 4+ VE.Direct devices — original Cerbo, or MK2 with a VE.Direct-USB converter

If you genuinely have four VE.Direct devices (uncommon, but possible — e.g. four MPPTs feeding a large solar array on a long cat) the original Cerbo's extra port may be worth keeping. Alternatively, a single VE.Direct-to-USB cable plugged into the MK2's USB-A port adds back a fifth VE.Direct port and the OS treats it identically. Most marine installs end up with 1–3 VE.Direct devices and never see this limit.

Installs with heavy Node-RED / Signal K usage — MK2

If you're integrating with N2K MFDs via Signal K, running custom Node-RED logic, or doing a lot of MQTT-driven home-automation work, the MK2's CPU and RAM make a real difference. The original tops out around 30–50 Node-RED nodes before lag becomes user-visible. The MK2 handles several hundred without complaint.

Migration notes — swapping original for MK2

For a working boat, the swap is about 30 minutes of physical work and 15 minutes of software:

1. Back up the original's settings. On Venus OS: Settings → General → Backup → write to USB stick.
2. Note the VRM site ID. Settings → VRM Online Portal → Site ID.
3. Power down the DC bus at the BMS contactor (or pull the Cerbo's input fuse).
4. Disconnect each cable, label as you go (most installers don't, then spend an hour re-tracing).
5. Unscrew the original from its mount. Mount the MK2 in the same holes.
6. Reconnect cables in the same positions:
   • VE.Bus → top RJ45 (single port, can't get this wrong)
   • VE.Can / BMS-Can → labelled RJ45s
   • VE.Direct → moved from 4 ports to 3, prioritise BMS-Can'd MPPTs first
   • HDMI → GX Touch
   • Ethernet → router
   • DC input → fused 8–70 V supply
7. Power up. The MK2 boots into Venus OS.
8. Restore settings from the USB stick: Settings → General → Restore.
9. Re-pair to VRM with the original site ID. History from the previous Cerbo carries forward.
10. Verify DVCC is still controlling: Settings → DVCC → check controlling BMS, charge-current limit, SVS / STS.
11. Run the verification test plan from the three-phase configuration guide if your install has multiple chargers.

If you don't restore from a backup, you'll need to re-pair every VE.Direct device individually (Settings → Battery monitor selection, Settings → Tank input setup, etc.). The backup file saves an afternoon.

Common questions

Does the Cerbo MK2 work with old MultiPlus-II / MPPT firmware? Yes. The Cerbo doesn't impose firmware versions on the devices it talks to. If your MultiPlus-II is on a 2021 firmware and DVCC was working with the original Cerbo, it will continue working with the MK2.

Can I run a Cerbo without a GX Touch? Yes. Most installs operate the Cerbo headless, accessing the UI via:

• VictronConnect over Bluetooth (MK2 only) or the local network (both).
• Web console at http://venus.local (mDNS) or the device's LAN IP.
• VRM Portal from any browser on the internet.

A GX Touch is convenient at the helm but is not required for the system to function.

Does the MK2 use less power? Idle consumption is the same (~3 W). The faster CPU is in a deeper sleep when idle, so the gap doesn't widen even when you stack more services on top.

Can I run two Cerbos on one boat? Technically yes, but it's not recommended. Only one can be the DVCC controller — the second adds complexity without redundancy (if the controlling Cerbo dies, the second doesn't automatically take over). For redundancy, install a single Cerbo and keep a spare in the spares kit.

Does the GX Touch 50 / 70 work with the MK2? Yes, both display models work identically with both Cerbo generations. The GX Touch 70 v2 (released alongside the MK2) adds a brighter screen and slightly better daylight visibility — useful at an outdoor helm but not strictly required.

Is the original Cerbo end-of-life? Not as of 2026. Venus OS continues to support it. Victron's pattern is to keep older generations in the catalogue for 5+ years after a successor lands, so expect support through at least 2029.

Putting it together

The Cerbo GX (either generation) is the device that turns a pile of independent Victron components into a coordinated marine system. Without one, DVCC isn't possible, multi-charger arrays can't share a BMS-published current limit, and the helm has no unified view of the electrical system.

For new builds, the MK2 is the default — better networking, faster UI, more headroom, and the same drop-in footprint. For existing installs that work, don't swap unless something's wrong. The original Cerbo is in the catalogue, supported by the same firmware, and most users won't notice a difference at the helm.

For the broader topology and configuration questions that the Cerbo orchestrates, see Configuring a three-phase Victron charger array, the Victron three-phase inverter/charger selection guide, the electric boat BMS guide, and the charger and inverter selection guide.