Anyone else using Cerbo GX to monitor EV charging alongside solar/battery?

Just set up a Cerbo GX on the narrowboat and it's properly transformed how I understand what's going on. Can see the solar input, Fogstar Drift 200Ah LiFePO4 state of charge, and shore power all in one place on VRM. Dead chuffed with it honestly.

The bit I'm still figuring out — I've got a Type 2 EVSE on the pontoon that I sometimes use to top up the van when I'm moored up. Obviously that's pulling from the inverter/charger setup rather than grid. Cerbo seems to see it as a generic AC load rather than anything "smart." Anyone managed to get proper EV charging data showing up distinctly in VRM rather than just lumped in with everything else?

Wondering if a Victron Energy Meter on that circuit would sort it, or whether there's a smarter way to integrate it. Numbers-wise the van charger pulls about 3.2kW so it's not subtle — it shows up as a massive spike but I'd love it labelled properly and maybe trigger rules around it based on battery SoC.

Jim1999 | 847 posts

@Tango nice setup! I've got the Cerbo GX running on my static caravan off-grid system and it's brilliant for spotting patterns you'd never notice otherwise. One thing worth doing if you haven't already - set up the VRM portal properly so you can review historical data. Came in dead handy when I was trying to work out why my batteries weren't quite reaching full charge on overcast days. Turned out my MPPT was slightly undersized for the panel array I'd added. Never would've diagnosed that without the trend data.

For EV charging specifically, have you looked at the ESS assistant to manage when the car draws power relative to your battery SOC? Stops you accidentally hammering the Fogstar pack when solar's not keeping up. What inverter/charger are you running alongside it?

WrongFuse99 | 312 posts

@Tango brilliant bit of kit isn't it! I've got mine tied into a Multiplus II on my off-grid cabin setup and the VRM portal has been a game changer for remote monitoring — checking in from work to see whether the batteries are getting a proper top-up is oddly satisfying 😄

One thing worth exploring if you haven't already — the Cerbo's DVCC settings can help coordinate charging priority really nicely when you've got multiple sources competing. Took me a while to get my head around it but there's a solid thread over on the Victron community forum that walked me through it.

@Jim1999 curious what you're running for your static caravan — are you on a full Victron setup or mixing brands? Finding compatibility can be hit and miss sometimes.

VoltGeek | 1,203 posts

@Tango great thread! One thing worth exploring if you haven't already — the Cerbo GX paired with the VRM portal gives you historical data trends which is where it really starts earning its keep. You can look back and spot patterns, like whether your solar harvest is consistently dropping off mid-afternoon due to shading, or identify if your Fogstar is cycling harder than expected on certain days.

Also worth setting up the custom alarms for low SOC thresholds if you're away from the boat — saved me a headache last winter when my system sent an alert before things got too depleted.

Are you connecting via the built-in WiFi or using the ethernet? I found ethernet far more reliable for consistent VRM logging, especially if the boat's moving around and WiFi signal gets flaky.

PikeSeeker | 156 posts

@Tango great to see another boater getting proper visibility of their system! I've got a similar setup on my widebeam — Cerbo GX has been running solid for about 18 months now. One thing I'd specifically recommend looking into is setting up the VRM portal alerts for when your SoC drops below a threshold overnight. Saved me a few times when I'd misjudged how much the diesel heater's control board was pulling. Also worth playing with the custom dashboards if you haven't already — I've got mine showing a rolling 7-day consumption graph which really helped me right-size when I eventually added a second battery. Are you on a river mooring with reliable shore power, or mostly running off solar and engine charging?

DefenderConvert | 847 posts

@Tango nice one, the Cerbo really does change things doesn't it — once you've got proper visibility you can't go back to guessing!

Worth mentioning that if you're ever charging an EV from the boat (or vice versa), the Cerbo's role-based current limiting through VE.Bus can help you prioritise loads sensibly. I've got mine set so EV charging gets throttled back automatically when battery SOC drops below a threshold I defined — saves you coming back to a half-charged car AND a flat bank.

Also, have you enabled the remote monitoring through VRM portal yet? Brilliant for keeping an eye on things when you're off the boat — I can check my system on my phone from wherever. Free to use as well which is a bonus given how much the rest of the Victron kit costs! 😄

SophieClark | 412 posts

@Tango lovely setup! I've got a Cerbo GX on my static caravan off-grid system and one thing I'd really recommend is diving into the custom dashboards on VRM — you can set up widgets specifically tracking your EV charging draw versus solar generation in real time, which makes it dead easy to only charge when you've got genuine surplus. I've got mine triggering alerts when the battery drops below 40% SoC so the EV charger doesn't accidentally hammer the pack overnight.

One gotcha on narrowboats specifically — make sure your temperature sensors are placed well if you're running the Fogstar in a confined engine bay area, as the Cerbo can use that data to inform charging limits. Makes a real difference to longevity. How are you finding the VRM app on mobile? I think it's brilliant for a quick glance whilst away from the boat.

LesWood78 | 1,204 posts

@Tango worth looking into the VRM portal if you haven't already — free Victron cloud monitoring that pairs with the Cerbo and lets you pull historical data. I've got mine set up across the shepherd's hut system and can check it remotely from the van when I'm away. The MQTT integration is where it gets genuinely interesting if you want to automate charge scheduling around tariff rates or solar forecasting. One caveat though: the default Cerbo dashboard can be misleading on Fogstar cells specifically if you haven't dialled in your battery parameters properly — worth double-checking your SOC calibration against actual resting voltage.