Can my lynx bmx ng turn off my inverter smart via ve.direct?

Been thinking about this one for a while so figured I'd throw it out there.

Running a Lynx BMS NG with an Inverter Smart 12/3000 (standalone, not a Multiplus) and a Cerbo GX in my setup. The BMS talks to the Cerbo over VE.Can no bother, and the Cerbo connects to the inverter via VE.Direct.

What I'm trying to nail down is whether the Lynx BMS can actually trigger a proper inverter shutdown through that chain — so BMS → Cerbo → VE.Direct → Inverter Smart. Like if the cells hit a low voltage limit, will the BMS instruct the Cerbo to pull the plug on the inverter automatically, or does it just throw an alarm and leave you to sort it manually?

I know the Multiplus handles this differently because it uses VE.Bus and the integration is tighter. VE.Direct feels a bit more one-way in my experience — mostly just reporting back to the GX rather than accepting commands from it.

Had a look through the Victron docs and it's not crystal clear. DVCC seems relevant here but I'm not 100% sure it covers inverter shutdown specifically, or just charge/discharge current limits.

Anyone running a similar topology? Particularly interested if you've tested what actually happens when the BMS raises a high/low cell alarm — does the inverter cut out or carry on regardless?

Would be good to get some real-world feedback rather than just spec sheet reading. Setup is off-grid full-time so getting this wrong isn't really an option.

The Lynx BMS NG doesn't have a VE.Direct port — it communicates via VE.Can to the Cerbo. The actual inverter shutdown path goes through the BMS's allow-to-discharge signal, which the Cerbo picks up and then acts on via DVCC.

Whether the Cerbo can actually command the Inverter Smart to shut down over VE.Direct depends on your firmware versions. There was a period where this was unreliable on standalone inverters (not Multis). Worth checking the Victron changelog — I recall there being a specific firmware requirement on the Cerbo side for DVCC to properly control non-Multi inverters.

Practically speaking, some people run a secondary hardwired BMS relay to the inverter's remote on/off terminal as a belt-and-braces fallback. I'd not rely solely on the software path for a proper low-voltage cutoff.

Good points from @DucatoProject. Just to add a bit more detail — the shutdown path you're after would typically go Lynx BMS NG → Cerbo GX (via VE.Can) → Inverter Smart (via VE.Direct). The Cerbo acts as the middleman and can absolutely pass along a BMS charge/discharge request to the inverter.

What you'll want to check in VenusOS is that the inverter is set to respond to BMS signals — look under the device settings for "ESS" or "external control" options. The Lynx NG's pre-alarm and disconnect signals should translate through correctly.

That said, I'd still recommend keeping a proper battery protect or relay in the loop as a hardwired backup — don't rely solely on the communication chain for protection. Has anyone here actually tested the response latency on this setup?

Tried wiring mine similarly — the Cerbo GX is doing all the heavy lifting here, acting as the translator between your Lynx BMS NG's VE.Can chatter and the Inverter Smart's VE.Direct instructions. Without the Cerbo in the middle you've essentially got two blokes shouting in different languages at each other. 🤷

Worth double-checking your DVCC settings in VEM OS though — if those aren't configured properly the BMS charge/discharge limits won't actually propagate to the inverter correctly even when everything's physically connected. Classic Victron "it works but does it actually work" situation.

Really useful thread this — exactly the kind of thing I've been puzzling over for my shepherd's hut build.

One thing I'm not clear on from the replies above: if the Cerbo GX is translating the BMS NG's VE.Can signals and then triggering the inverter shutdown via VE.Direct, what's the typical response time like? Is it fast enough to actually protect the cells in a genuine low-voltage event, or is there meaningful lag between the BMS flagging an issue and the Inverter Smart actually cutting out?

Also wondering whether the DVCC settings in VE.OS play into this at all — I've seen mention of DVCC effectively giving the Cerbo more direct authority over connected inverters. Would that tighten up the response versus relying purely on the BMS's own disconnect signalling?