Can Cerbo GX turn things on and off?

Been going down a similar rabbit hole recently with my motorhome build, so this feels timely.

Running a 48v lithium bank (Fogstar Drift cells) with a Victron Orion-Tr Smart stepping down to 12v for the 12v loads — lighting, water pump, that sort of thing. The question I kept bumping into was whether the Cerbo GX could actually control when that converter runs, rather than just monitor it.

Short answer from my experience: yes, but it depends on the variant.

The Orion-Tr Smart (non-isolated, in my case) can be switched via a remote on/off wire. If you wire that into one of the Cerbo's relay outputs, you can trigger it based on virtually any condition in the system — time of day, state of charge, whatever. Set it up through Node-RED on the Venus OS if you want proper flexibility, or use the built-in relay rules for simpler logic.

I've got mine switching off overnight when the SOC drops below a threshold, stops the converter quietly draining the bank through standby draw. Made a noticeable difference to morning SOC readings.

Worth noting though — the Cerbo relays are fairly low current (I think 4A?), so you're not switching the load directly, just signalling the converter. Check your wiring accordingly.

Has anyone done this with the isolated Orion variants? Curious whether the remote input behaves the same way. Also wondering if anyone's used the virtual switches in Venus OS rather than the physical relay — seemed fiddly last time I looked but that was an older firmware.

@Geordie the Cerbo can definitely switch things via its relay outputs — there's two on-board relays you can configure with conditions in VRM or locally.

That said, for controlling an Orion-Tr Smart specifically, the remote on/off pin is your friend. Wire that to a Cerbo relay and you can automate it based on SOC, voltage, whatever suits.

I do something similar in my cabin setup — Cerbo kills non-essential loads when the bank dips below a set threshold. Works reliably.

Worth reading the Cerbo GX manual section on relay programming, it's actually pretty clear for Victron docs. Node-RED via Venus OS Large gives you way more control if you want to go deeper down that rabbit hole.

@Geordie the Cerbo relay is brilliant for this but don't overlook the virtual switches in VRM — you can trigger the Orion remotely without even being near the van, which is either very clever or a great way to accidentally flatten your starter battery from a Tesco car park.

On the boat I've got the Cerbo relay controlling my Orion-Tr Smart via the remote on/off pin — works a treat. What I'd add is that the relay logic can be chained to battery state of charge thresholds, so you can set it to only allow the DC-DC to run when your lithium bank is above, say, 20% SOC. Protects the cells without you having to think about it.

Worth checking your Orion-Tr Smart variant though — the isolated version has a dedicated remote H/L terminal that plays nicely with the Cerbo relay, whereas the non-isolated models are slightly different in how you wire that control circuit. Had to double-check my own wiring on this before I got it right.

@KevScott that remote on/off pin approach is exactly what I've been eyeing up for my garden office build — but here's what I can't figure out: does the Cerbo relay output supply enough voltage/current to actually drive the Orion's remote pin directly, or do you need an intermediary relay in between?

The Victron docs are characteristically... thorough in the way that means I've read the same page four times and I'm still not certain.

Also curious whether you've set any conditions on when the relay fires — like only enabling the Orion-Tr if battery SOC is above a certain threshold? Seems like that'd be the sensible approach to stop the DC-DC hammering a depleted bank, but I don't know if the Cerbo's relay logic is flexible enough to handle that without turning into a full MQTT project.

Worth adding that if you're using the remote on/off pin approach @KevScott mentions, just double-check the voltage logic on your specific Orion-Tr Smart variant — some want a high signal to enable, others pull low to disable, and getting that backwards causes head-scratching. I wired mine up on a campervan conversion last summer and initially had it doing exactly the opposite of what I intended!

@VoltPaddy regarding your garden office concern (whatever it was before the post got cut off), the Cerbo's Node-RED integration is worth exploring if the built-in relay logic feels too limited — you can build proper conditional flows combining battery SOC, temperature, and time-of-day triggers all in one place. Much more flexible than juggling separate automations.