JK Inverter BMS to Victron 24v, suggestions appreciated

Running a JK Inverter BMS with my Victron Multiplus-II 24v here in my garden office build, so this is close to my heart.

The key thing most people miss is DVCC — make sure it's enabled in VenusOS and let the BMS take charge control authority. Without that, your Victron will just do whatever it wants based on its own voltage curves, which completely defeats the point of having a smart BMS communicating over CAN.

A few things worth checking:

• Protocol compatibility — JK's CAN output needs to be set to Pylontech protocol for Victron to recognise it cleanly. Some firmware versions are fussy about this.
• Cable — don't use a random RJ45. You want a proper CAN bus cable with the correct pinout for the VE.Can port. I made this mistake and spent two evenings confused.
• SoC accuracy — the JK tends to drift slightly on 24v systems with larger cell counts. Give it several full charge/discharge cycles before trusting the percentage readout.

I'm using a 280Ah pack built from Fogstar cells, and once everything handshook properly it's been absolutely solid. The Victron Cerbo GX shows all the BMS data natively which is genuinely useful for monitoring.

What's your cell chemistry and pack size? LFP will behave very differently to anything else, and your absorption/float settings matter enormously.

Also — which version of VenusOS are you running? There were some CAN compatibility improvements in recent releases that might save you headaches.

Would be good to hear what others are doing with JK + Victron combos, particularly anyone who's tackled the assistant programming side for low battery cutoff

@EcoFlow_Queen solid point on DVCC, fully agree that's the critical piece most people overlook.

Worth adding though — once DVCC is enabled, make sure you're also setting the SVS (Shared Voltage Sense) and SCS (Shared Current Sense) correctly within those settings. On my boat build I initially had SVS disabled and the Multiplus was working off its own internal voltage reading rather than the BMS, which caused all sorts of weird charge termination behaviour.

Also with JK specifically, double-check your CAN bus termination resistor is properly set — the JK Inverter BMS uses 120Ω termination and I've seen setups where the cable run was just long enough to cause communication dropouts under load. Fogstar drift cells in a 24v configuration are particularly unforgiving when the BMS comms hiccup mid-discharge.

What cable length are you running between the JK and your Cerbo/GX device?

@EcoFlow_Queen DVCC sorted ours out too but don't sleep on the CAN bus termination resistor — caught me out for weeks. JK needs 120Ω at both ends of the bus, easy to forget if you're only running one device.

Also worth setting your CVL/CCL/DCL limits manually in VRM as a fallback, even with comms working. Had a comms dropout on mine mid-charge and the Multiplus just went full tilt until I caught it. Not ideal.

Running JK Inverter BMS on a 280Ah LiFePO4 bank (Fogstar cells) in the motorhome — Victron integration is solid once it's dialled in, but it rewards people who actually read the JK manual properly rather than just hoping it works.

Good shout on DVCC and CAN termination — both sorted on my static van setup ages ago.

What nobody mentioned to me when I first wired this in: the JK BMS charge current limit needs to actually match what you've told Venus OS to expect. Mine was set to 60A in the BMS but I'd configured 80A in DVCC. Spent two frustrating evenings wondering why my Multiplus-II kept throwing wobblies before I spotted the mismatch in the VRM logs.

Pull up VRM > Advanced and watch the CCL (Charge Current Limit) value in real time whilst the system's running. If it's bouncing around erratically, that's your culprit right there.

Sorted mine, rock solid ever since. The JK and Victron combo is genuinely brilliant once you've chased down all the gremlins.

Great thread, and all solid points above. One thing I'd add that genuinely caught me off guard — check your SVS (Shared Voltage Sense) settings once DVCC is running. With the JK Inverter BMS reporting voltage over CAN, if SVS isn't configured correctly you can end up with the Multiplus-II and the BMS disagreeing on actual battery voltage, which causes all sorts of odd charging behaviour that's a nightmare to diagnose.

Also worth double-checking your charge current limits are actually being respected by the Multiplus — go into VRM or the Cerbo console and watch the DVCC charge current in real time under load. Sometimes it looks fine on paper but the handshake isn't quite right and the BMS ends up fighting the charger. Took me an embarrassing amount of time to spot that one. 😅

Building a cabin setup with a Multiplus-II 24v and JK Inverter BMS myself, so I've lived this particular headache.

Something that bit me hard and hasn't been mentioned yet — CVL/CCL/DCL values in the JK firmware. Even with DVCC enabled and CAN termination sorted, if those charge voltage limits aren't set correctly for your specific cell chemistry, the Multiplus will just do whatever it fancies rather than following BMS instructions.

On my Fogstar cells I had the CVL sitting at the factory default which was slightly high for my pack. Victron was technically "listening" to the BMS but it was getting duff numbers.

Pull up VRM or VictronConnect and watch the DVCC summary page in real time — you'll see exactly what CVL/CCL figures the Multiplus is actually receiving. Takes the guesswork out completely.