Pylontech and Orion TR Smart DC/DC? Cerbo GX?

Been going back and forth on this one for my garden office build and could do with some input from anyone who's actually running this combination.

I'm planning to use a couple of Pylontech US2000s with an Orion TR Smart 12/12-30 to top them up from a vehicle alternator when I occasionally run a cable out to the van. The Cerbo GX will be the brains of the operation alongside a Multiplus.

My concern is around the Pylontech BMS and how reliably it communicates shutdown commands through the Cerbo when things go wrong. I've read a few posts elsewhere suggesting the BMS protection isn't always bulletproof — particularly around over-voltage situations if the Orion TR is pushing charge in without the Cerbo properly coordinating the cutoff.

A few specific questions:

• Does the Cerbo actually receive BMS charge/discharge limits from the Pylontech over CAN bus and relay those to the Orion TR Smart reliably?
• Should I be setting conservative voltage limits directly in the Orion TR as a hardware-level backup, rather than relying solely on the Cerbo to manage it?
• Anyone using VE.Smart Networking here to keep the Orion TR in sync with the rest of the system?

I'm wary of depending entirely on software-level protections when lithium is involved. Feels like the sort of thing where you want belt and braces.

Would be really interested to hear from anyone who's got this stack running in anger, especially in a similar part-time or remote setup rather than a full-time off-grid system.

Running almost exactly this in my van so can offer some firsthand experience.

The Pylontech/Cerbo combo is solid — the CANbus integration means the Cerbo reads state of charge, cell voltages, temps, everything natively. No faffing about with manual settings.

One thing worth knowing: the Orion TR Smart doesn't communicate with the Cerbo directly, so you'll want to check your charge profile is set correctly in the Orion's app rather than assuming the Cerbo is managing it. The Pylontechs want a fairly specific charge voltage (around 53.2V for 48V units).

Also make sure your VE.Smart networking is set up if you're running other Victron kit — lets the devices share battery data and makes the Orion behave more intelligently.

What solar input are you planning? That'll affect how much the DC-DC charger actually gets used in practice.

Worth flagging something @GeorgeJohnson83 might not have considered — the Orion TR Smart in non-isolated form cannot be used between two battery banks sharing a common negative. For a garden office fed from a vehicle or separate source that's fine, but double-check your topology first.

On the Cerbo GX side, Pylontech US2000s talk to it natively over RS485 using a VE.Can-to-RS485 cable — no third-party BMS needed. The Cerbo will display individual cell voltages, state of health, the lot. Genuinely impressive integration.

One practical gotcha I hit on my narrowboat build: make sure your Pylontech firmware is current before commissioning. Older firmware versions can cause the Cerbo to throw spurious alarms. Victron's VictronConnect app walks you through it easily enough.

Don't forget the Cerbo needs a VE.Can connection to talk to the Pylontechs properly — USB-to-CAN adapters and hope are not a valid comms strategy, ask me how I know 🚢

Has anyone actually tried running two US2000s in parallel with the Cerbo and had issues with the state of charge readings drifting between the two batteries? I've got a similar setup planned for my static caravan and I'm a bit worried about whether the Cerbo accurately represents both units or just treats them as a single bank.

Also — @ExSquaddie49 you've mentioned the non-isolated Orion issue, but is the isolated version genuinely plug-and-play with this setup or are there still gotchas to watch for? I've seen the Victron docs but real-world experience is always different. Trying to nail down whether a 30A isolated Orion TR Smart is sufficient for a garden office load or whether I should be looking at the 50A version.