Victron unveils faster Cerbo GX MK3 and emergency reverse charging for Orion XS

Victron recently answered two of the most common complaints about two of its most popular products. The Cerbo GX gets its third hardware generation, with a much faster processor for owners who have pushed the MK2 to its limits. The Orion XS hardware is unchanged, but a firmware update finally lets it charge in reverse, for now only to rescue a flat starter battery.

Cerbo GX MK3

Victron unveiled the original Cerbo GX at Metstrade in the fall of 2019. In late 2023, the MK2 was announced with some changes to the port configuration, but the underlying processor carried on unchanged. Now, seven years after the original, we have the MK3 with an identical port selection but a much-upgraded processor.

GX Model	SoC	RAM	Cores & speed	Arch.
Cerbo GX MK1 & MK2	Allwinner A20	1 GB DDR3	2 × Cortex-A7 @ 1.2 GHz	32-bit
Cerbo GX MK3	TI AM625	1 GB DDR4	4 × Cortex-A53 @ 1.4 GHz	64-bit
Ekrano GX	Allwinner H3	1 GB DDR3	4 × Cortex-A7 @ 1.2 GHz	32-bit
Nucleo GX	Allwinner H3	1 GB DDR3	4 × Cortex-A7 @ 1.2 GHz	32-bit
MultiPlus-II GX / EasySolar-II GX	Allwinner H3	512 MB DDR3	4 × Cortex-A7 @ 1.2 GHz	32-bit

Overall, the Cerbo GX hardware has held up surprisingly well. But Victron has added a lot of functionality and that new functionality places additional demands on the hardware. Interestingly, the recently introduced Nucleo GX uses the same processor as the Ekrano GX, rather than the TI AM625 in the Cerbo MK3.

Feature	Allwinner A20 (Cerbo GX MK1 & MK2)	Allwinner H3 (Ekrano GX, Nucleo GX)	TI Sitara AM625 (Cerbo GX MK3)
Release year	2013	2014	2022
Architecture	32-bit ARMv7-A	32-bit ARMv7-A	64-bit ARMv8-A
CPU cores	2 × Cortex-A7 @ 1.2 GHz	4 × Cortex-A7 @ 1.2 GHz	4 × Cortex-A53 @ 1.4 GHz
Process node	40 nm	40 nm	16 nm
RAM as fitted	1 GB DDR3	1 GB DDR3	1 GB DDR4

Comparing the hardware used by the Cerbo GX MK1 and MK2, Ekrano, Nucleo, and finally Cerbo GX MK3 shows the MK3 to be the big outlier. The Ekrano GX and Nucleo GX move to quad CPU cores but little else. The TI AM625 in the MK3 adds a 64-bit architecture, faster cores, newer RAM technology, and the reduced heat and power consumption of a 16-nanometer fabrication process.

Although there are no port changes and most of the other specifications remain the same, there is one major spec difference between the MK2 and MK3. The maximum number of VE.Direct devices goes from 15 on the MK2 to 25 on the MK3. Fifteen devices may sound like a lot, but I see more and more installs with solar chargers, DC-to-DC chargers, and AC-to-DC chargers all ganged in groups of two to as many as six of each type of charger. JJust those three charger types, each in a group of six, exceed the limit.

Since the Cerbo was introduced, we have seen Node-RED, Signal K server, third-party temperature sensor support, digital switching, and many more features added to Venus OS. Those features all require resources, and when paired with ever-larger installations, they can exhaust the existing hardware. Victron says the vast majority of installations continue to run smoothly on the existing hardware. However, more complex installations with greater use of Node-RED, Signal K server, and higher component counts may find the limits of the current hardware.

One of the indicators I’ve noticed with MK1 and MK2 Cerbos is the time taken to load Node-RED. If you load Node-RED through Victron’s proxy, as is the default via VRM, it takes quite a while, but much of that delay results from proxying traffic. However, just loading the actual Node-RED interface and nodes is noticeably slower on a Cerbo than on a Raspberry Pi 4 or 5 also running Venus OS. The MK3 seems to be just as fast as the Pi. Otherwise, the MK3 feels faster, but who knows; maybe that’s a placebo effect.

Orion XS bidirectional charging

For several years, one of the worst-kept secrets of the Orion XS line of DC-to-DC chargers has been the hardware’s ability to support bidirectional charging. That means that, once the software is implemented, a DC-to-DC charger set to send energy from an engine battery bank to a house battery bank could also turn around and charge the engine battery when the house battery bank is being charged. Unfortunately, numerous conversations over the last few years revealed that the logic of how to control this feature proved more difficult than Victron originally thought.

This fall, Victron released updates to both VictronConnect and the Orion XS firmware to enable what it calls emergency reverse charge. This mode allows Orion XS 12/12-50A, 12/12-70A, and 1400 chargers to charge in reverse at up to half their rated current. So, an Orion XS 12/12-50A that is normally capable of charging at up to 50 amps can charge in reverse at up to 25 amps. Charge voltages are fixed at 14.4 volts for a 12-volt nominal battery and 28.8 volts for a 24-volt nominal battery. Lastly, charging is limited to 15 minutes, with a fixed 5-minute cool-down and settling period afterward.

Emergency reverse charging is only available when the Orion XS is in charger mode (not power supply mode) and charging is off because of either input voltage lockout or engine shutdown detection. At least currently, emergency charging can only be activated from within VictronConnect version 6.43 or later. AAt first, I was a little surprised to see both currents shown as negative numbers. However, seen next to the standard charging modes, that display decision makes sense. The app indicates that both batteries’ energy flow at both batteries is the opposite of standard operation.

I have tried it a few times and everything implemented works exactly as advertised. I’m encouraged that this is a starting point for more bidirectional functionality. The biggest thing I would love to see is a lower amperage but continuous reverse charging ability. For example, a DC-to-DC charger installed to send power from the engine alternators to the house bank could also be used to tend the start batteries. Typically, that tending doesn’t require significant amperage. So, anything even approaching the half forward charging achieved in emergency charging would be great.

Neither update is flashy, but both show Victron listening. The MK3 gives heavy Node-RED and Signal K users the headroom they have been asking for without changing a single port. The Orion XS update turns a long-rumored capability into something you can use the day your starter battery lets you down. If Victron follows through on the reverse charging features it says are coming, that story is just getting started.