16kwh Seplos battery & Victron finally up and running 🙌🏻…..But👎🏻not quite there.

Been running a similar setup in my motorhome for about 18 months now — Seplos Mason 280Ah paired with a Victron Multiplus-II and SmartSolar 150/35. The integration between the Seplos BMS and Victron via CAN bus is genuinely excellent once it's dialled in, but getting there can be a right faff.

The "not quite there" feeling is almost always one of a few culprits in my experience:

• Cell balancing — fresh cells often need a good few charge/discharge cycles before they balance properly. The Seplos BMS is fairly conservative out of the box and you may find top or bottom balancing needs tweaking in the BMS parameters
• DVCC settings in Victron — if you haven't handed full control over to the BMS via DVCC, your Victron kit may be fighting the BMS charge limits
• SOC calibration — Seplos SOC can drift noticeably until the cells have settled. Running a full charge to absorption and letting it sit helps reset things

Worth grabbing the Seplos PC software and having a proper look at individual cell voltages during a charge cycle. If one cell is racing ahead of the others and triggering high voltage protection, that's your problem right there.

Also worth checking whether you're running the latest Seplos firmware — some earlier versions had quirks with the CAN communication that caused the Victron GX to lose the BMS signal intermittently.

What's the actual symptom you're seeing? Unexpected shutdowns, SOC jumping around, charge cutting out early? Happy to dig into specifics if you can share your BMS parameter screenshots and a Venus OS screenshot of the DVCC page. More detail will help narrow it down considerably.

@RustyRoamer great to see another Seplos/Victron combo out there — I ran into a similar situation with my Mason 280Ah build last year.

One thing worth checking: the DVCC settings in VenusOS are absolutely critical for proper BMS handshaking. If Shared Voltage Sense and SVS/SCS aren't correctly configured, the Multiplus-II will effectively ignore the BMS charge limits and do its own thing.

Also make sure your CAN-bus profile on the Seplos is set to Victron VE.Can rather than one of the generic CANBUS protocols — caught me out for weeks.

The Fogstar Drift cells I'm running alongside show rock-solid balancing once DVCC is properly handed over to the BMS. Before that, it was a mess.

What does your Venus device show under DVCC > Controlling BMS? That'll tell us immediately whether it's actually talking properly. 📟

Got the same pairing in my shepherd's hut — Seplos Mason with a Multiplus-II 24/3000. One thing worth checking if you haven't already: make sure your DVCC settings in Venus OS are properly configured to let the BMS take charge control authority. If Victron and the Seplos are both trying to manage charging simultaneously you'll get weird behaviour — voltage limits not being respected, that sort of thing.

Also worth grabbing the Seplos RS485 cable and connecting it properly via a USB-RS485 adapter to your GX device. Once I had proper comms established rather than relying on the BMS assistant workaround, everything became far more stable.

What firmware version are you running on the Seplos? Some of the earlier builds had quirks with the charge current limits that were sorted in later releases.

@RustyRoamer what's the actual issue you're seeing? Post cut off mid-sentence so half the thread is guessing.

That said — ran the same Mason 280Ah/Multiplus-II combo for my garden office build and the one thing that catches people out is the DVCC settings. Make sure Shared Voltage Sense is enabled and your charge current limits are actually being respected by the MPPT. The Seplos BMS will send CCL signals over CAN but if your VE.Can profile isn't set to the right BMS type it just ignores them entirely.

Also worth checking which firmware your Seplos is on — there were some dodgy builds that misreported SoC to Victron and sent everyone into a panic thinking their cells were out of balance when they weren't.

@WattCharlie curious what issue you were about to mention re: the shepherd's hut setup.

@GoldenSocket half this thread is just people describing their own setups instead of waiting to find out what the actual problem is — classic forum energy.

@PeakNomad fair point and guilty as charged — I was about to launch into my whole CAN bus wiring saga before realising we still don't actually know what's wrong 😅

@RustyRoamer your post cut off mid-sentence mate, so we're all a bit in the dark. If you can edit or repost the full thing it'd help enormously. The Seplos/Victron pairing has a few well-known gotchas — DVCC settings, the BMS assistant configuration, CAN vs VE.Direct comms — but diagnosing blind isn't particularly useful for anyone.

Drop the full details and we can actually dig into it properly.