Multi RS 48/6000-230V problem in VRM/Victron Connect

Bit of a saga to share, and wondering if others have run into similar.

Recently swapped out my old MultiPlus II 48/3000 on the narrowboat for a Multi RS 48/6000 — primarily because I wanted the extra headroom during those winter months when I'm running more loads and the backup demands are higher. No solar input on this particular unit, just using it purely for AC charging and inverting.

The trouble started almost immediately in VRM. The dashboard is showing the device, but some of the readings are either missing or clearly wrong — output power figures look off, and Victron Connect on my phone isn't displaying the charging status correctly. It seems to think the unit is in a different mode than it actually is.

A few things I've noticed:

• The Multi RS seems to behave differently in VRM compared to the MultiPlus II, even with identical firmware on the Cerbo GX
• Charger-only mode configuration feels less intuitive on this unit
• Some parameters that were straightforward to set on the MultiPlus II appear buried or behave unexpectedly

My suspicion is there's something in how the Multi RS reports itself to the GX device — it's a fundamentally different architecture to the MultiPlus range, and I'm not sure VRM has fully caught up yet.

Has anyone else made this specific swap and encountered oddities in VRM or Victron Connect? Particularly interested if anyone's running one in charger-only mode without MPPT. Would be useful to compare notes before I raise a formal support ticket with Victron.

@CraigCross ooh the Multi RS is a different beast entirely to the MultiPlus II — different comms protocol if I remember right? Think it uses SolarEdge-derived stuff under the hood which can confuse VRM a bit initially.

Had something vaguely similar when I swapped kit at the cabin, VRM just... sat there looking blank for ages. Ended up being a firmware thing.

Few questions though:

• Are you on the latest Venus OS on your GX device?
• Is it a Cerbo GX or something older?
• VE.Can or VE.Bus connection?

The Multi RS specifically needs VE.Can I think — not VE.Bus — which catches people out constantly. That might actually be your whole problem right there if you've wired it like the old MultiPlus.

Worth double-checking the Victron compatibility matrix too, it's surprisingly specific with the RS range.

@EcoFlow_Gal is right — the Multi RS uses a completely different VE.Can backbone rather than VE.Bus, so your Cerbo/GX device needs to be talking the right language or VRM just stares at it blankly like my mother-in-law at a WiFi router.

Hey @CraigCross, yes been through something similar when a mate upgraded his setup. Worth double-checking you've got the Multi RS firmware fully up to date before anything else — there were some early versions with proper gremlins in VRM reporting. Also make sure your Cerbo GX firmware is current too, as older versions had limited support for the RS series. One thing that caught us out was the VE.Can termination — you need the 120 ohm terminator fitted correctly at both ends of the bus, otherwise comms get flaky and you'll see all sorts of weird dropouts in VictronConnect. What firmware version are you running on the Cerbo? And are you seeing complete dropouts or just incorrect data being displayed? That'd help narrow it down. Also worth checking the VE.Can cable is seated properly — sounds obvious but it's bitten people before!

@CraigCross one thing that trips people up with the Multi RS — it needs a specific VE.Can profile set correctly on the Cerbo. Go into the Cerbo settings, find the VE.Can port config, and make sure it's set to VE.Can & Lynx Ion BMS or just plain VE.Can depending on your battery setup. Wrong profile and it'll just sit there invisible.

Also worth checking your firmware on both ends — the Multi RS had some early bugs where VRM showed it offline even when physically connected fine. Victron pushed fixes but you need fairly recent builds on both the Cerbo and the unit itself.

Had a similar headache when I added a Cerbo to my garden office setup, different kit but same VE.Can nonsense. Victron Connect on your phone should at least show it over Bluetooth directly as a sanity check.