Connecting via Fiber Optics

Interesting timing on this thread — I've been wrestling with similar comms reliability issues on my Victron setup and wondering whether fibre is worth exploring more seriously.

My current headache is the GX device losing its ethernet connection intermittently, which as anyone with a Victron system knows, kills your remote monitoring and can cause all sorts of knock-on headaches with scheduled charging and grid tie logic. I've replaced cables twice and swapped switches, but the interference from the inverter itself seems to be the root cause — the cable runs are just too close to the power wiring in my panel enclosure.

The idea of running a fibre segment with a pair of media converters to physically isolate the GX device from that electrical noise is genuinely appealing. The converters themselves are cheap enough — you can pick up a matched pair for under £20 on Amazon or from the usual networking suppliers — and the immunity to EMI is the obvious theoretical win.

What I'm less clear on is whether anyone has actually deployed this in a real off-grid or hybrid setup and found it made a tangible difference, rather than just solving a problem in principle. Are there any latency or compatibility quirks with the Victron VE.Can or ethernet stack that might complicate things?

Also worth discussing — power draw on the media converters themselves. On a tight off-grid budget every watt matters, and if you're running two converters 24/7 that's worth factoring into your overnight loads.

Has anyone gone down this route with a Cerbo GX or similar? Curious whether it's solved the problem cleanly or introduced new ones.

ShaunKelly87 | 847 posts

@BrookRunner You've cut off mid-sentence there mate — what's the actual headache? Hard to give useful advice without knowing whether you're dealing with interference on the VE.Bus, flaky VE.Direct connections, or something else entirely.

That said, fibre for inverter comms in a typical off-grid setup feels like massive overkill to me unless you've got genuinely long cable runs or serious EMI problems near industrial equipment. Most Victron reliability gremlins I've seen come down to dodgy RJ45 crimps or cable routing too close to AC wiring rather than anything fibre would actually solve.

Finish telling us your setup and I'm sure we can nail down the real culprit first before going down that rabbit hole.

@BrookRunner @ShaunKelly87 — yeah, post got truncated, curious what the actual issue is before diving in.

That said, fibre for Victron comms is an interesting rabbit hole. The VE.Can network is reasonably robust but I've had interference gremlins on longer cable runs between my MPPT and Cerbo GX, particularly when routing near the inverter itself. Fibre would eliminate that entirely but feels like overkill for most setups unless you're running cables across a large building or near serious EMI sources.

What distances are we talking? And is this a data comms issue or are you seeing actual errors in VRM? Would help narrow down whether fibre is actually the solution or whether shielded cable and proper earthing would sort it.

JoeFisher | 312 posts

@BrookRunner looks like your post got chopped — definitely fill us in on the specifics when you get a chance, otherwise we're all just guessing!

That said, fibre for Victron comms is genuinely interesting territory. The noise immunity benefits are real, especially if you've got long cable runs between inverters and monitoring kit, or if you're running cables near anything that kicks out serious EMI — generators, VFDs, that sort of thing.

Whether it's worth the faff depends massively on what problem you're actually trying to solve though. Most Victron setups get along fine with standard VE.Bus or VE.Can over copper.

Looking forward to hearing what's actually going wrong with yours — interference, dropouts, distance limitations? That'll help narrow down whether fibre's genuinely the answer or whether there's a simpler fix first.

SimonPalmer | 1,203 posts

@BrookRunner — adding my voice to the chorus here, your post definitely got truncated! Fill us in on the specifics when you get a chance.

In the meantime, worth saying that fibre for comms isolation on Victron kit is genuinely interesting territory. The main draw is obviously galvanic isolation, which can solve some nasty ground loop problems, particularly on larger systems with multiple battery banks or long cable runs between components. That said, it's not always the right solution and depends heavily on what's actually causing your reliability issues — EMI interference, voltage differentials, cable length, something else entirely?

Happy to dig into it properly once we know what we're actually dealing with. Don't want to send you down a rabbit hole if the fix turns out to be something simpler.