Monitoring EG4 Solar Charge Controllers

Has anyone had much luck getting EG4 charge controllers to talk nicely with other monitoring setups? I'm running a Victron system on the narrowboat and I've been toying with the idea of adding an EG4 controller for a secondary array, but the monitoring integration side of things is making me hesitant.

A few questions I can't find clear answers to:

• Does the EG4 play well with Victron's GX ecosystem, or are you essentially stuck with their own app?
• Is there a way to pull data into something like Home Assistant via RS485 or Modbus?
• Anyone using a Raspberry Pi as a bridge to get everything into one dashboard?

I've seen some posts on American forums suggesting the RS485 adapter route works, but I'm not sure how well that translates to UK setups where we tend to favour Victron as the backbone.

My main concern is ending up with two separate monitoring systems — the Victron Cerbo GX on one screen and some standalone EG4 app on another. On a narrowboat space is tight and I'd rather have everything consolidated if possible.

Would love to hear from anyone who's actually done this rather than theoretical suggestions — what worked, what didn't, and whether it was worth the hassle compared to just sticking with an additional Victron MPPT and keeping it all native?

Hey @ExJoiner, interesting one this! I've not personally mixed EG4 with Victron on a boat setup, but worth flagging that EG4 controllers typically use RS485/Modbus for comms rather than Victron's VE.Direct or VE.Can protocols, so they won't natively appear in VRM or the Cerbo GX without some workaround.

A few folks have used a Raspberry Pi running Node-RED or similar to bridge the two, which works reasonably well but does add another point of failure — not ideal on a narrowboat where you might be away from easy repair options for weeks.

Have you considered whether a Victron SmartSolar might just be the simpler path if you're already invested in that ecosystem? Genuinely curious what's drawing you toward the EG4 — price difference, availability, specific specs? That might help narrow down whether the integration headache is worth it.

@ExJoiner the integration headache with EG4 controllers is the comms protocol — they typically use a proprietary RS485 implementation rather than proper VE.Direct or VE.Can, which means Victron's GX devices won't natively recognise them.

What some people have done successfully is run a Raspberry Pi alongside the Cerbo GX, pull data from the EG4 via a USB-RS485 adaptor, then push MQTT into VRM or use the Node-RED integration. It works, but it's faff.

Honestly, if your core system is already Victron, you'd save yourself considerable grief just adding a Victron MPPT — even a 100/30 or 100/50 fits neatly into a narrowboat setup and drops straight onto VE.Smart networking with your existing kit. The EG4 units make more sense when you're building an EG4-centric system from scratch rather than bolting onto an established Victron installation.

@ExJoiner worth knowing that EG4 controllers often expose a Modbus RTU register map over that RS485 port, even if EG4 don't advertise it prominently. I've had reasonable success pulling data from similar Chinese-manufactured controllers using a Raspberry Pi running Node-RED, bridging into MQTT and then feeding Victron's VRM via a GX device.

The critical bit is obtaining the actual register map — sometimes buried in firmware release notes or extractable via community reverse-engineering threads on GitHub.

That said, on the boat I've found keeping charge controllers native to the Victron ecosystem (MPPT 100/30 in my case) considerably reduces integration friction. If you're already invested in Cerbo GX, adding a non-Victron controller always introduces a weak link.

What's drawing you toward EG4 specifically — cost, amperage rating, something else? That context would help narrow down whether the integration effort is genuinely worthwhile.

@AshChild is right about the Modbus registers, and that's actually the path I went down with my cabin setup. Once you've got the register map (sometimes you have to dig through firmware release notes or third-party GitHub repos rather than official docs), you can pull data into a Raspberry Pi running Node-RED or similar and push it into VRM via a Victron MQTT bridge.

The sticking point on a narrowboat specifically is going to be noise on the RS485 line — 12V DC environments with inverters nearby can introduce enough interference to cause intermittent dropped frames. Worth using a proper isolated USB-to-RS485 adapter (the ones with the FTDI chip rather than cheap CH340 clones) and keeping cable runs twisted and short.

The Victron ecosystem doesn't natively speak to EG4, so manage expectations — you're effectively building a custom integration rather than plug-and-play.