The display in VRM and Connect is wrong regading charging/discharging

Noticed something that's been niggling at me for a while now and curious whether others have hit the same wall.

Running a Victron setup in the motorhome — MultiPlus-II, Cerbo GX, pair of Fogstar Drift lithiums — and I've had moments where VRM is telling me one thing while the physical reality is clearly another. Most recently I caught it showing "Discharging" on both VRM and Victron Connect while the battery was quite obviously pulling amps in from shore power. SOC was climbing, current flow confirmed it on the shunt, but the labels were contradicting everything.

Mine wasn't the ESS scenario exactly (motorhome setup is a bit different), but the underlying weirdness feels identical — the data is broadly correct, the state label is just wrong.

A few things I've wondered:

• Is it a firmware timing issue where the label lags behind a mode switch?
• Could it be something in how the MPPT, inverter, and BMS are all reporting simultaneously and confusing the Cerbo?
• Or is VRM just occasionally painting the wrong picture from aggregated data?

It's mostly cosmetic I suppose, but when you're trying to diagnose an actual fault, staring at a dashboard that says "Discharging" when you know you're charging erodes your confidence in the whole monitoring stack pretty quickly.

Anyone else seen this, particularly on more complex setups with multiple charge sources? Wondering if there's a known fix or whether it's just one of those quirks you learn to live with.

PikeAndrea | 47 posts

@BayPete I had exactly this with my Fogstar Drift cells and Cerbo GX. The root cause in my case was that the battery monitor in VRM was set to the wrong source — it was pulling SOC data from the MultiPlus rather than the dedicated shunt. Worth checking in Remote Console under System Setup → Battery Monitor and confirming it's pointed at your BMV or SmartShunt if you've got one installed.

Also double-check whether your Drifts are configured with the correct capacity figure in the BMS settings — an undersized capacity value will make charge/discharge current percentages look completely backwards relative to what VRM reports.

What BMS are you running with the Drifts? That might narrow it down further.

@BayPete Fogstar's UART comms and Victron's DVCC playing nicely together is basically a myth propagated by people who've never actually tried it at 2am in a layby.

AGM_Guy | 203 posts

@BayPete Worth checking whether your Cerbo is actually receiving valid SOC data from the BMS or just falling back to its own voltage-based estimation — they can look identical on the dashboard but behave completely differently. Pop into Remote Console and check Settings > System Setup > Battery Monitor. If it's set to "Automatic" it might not be picking up the Fogstar BMS at all, and you'll get misleading charge/discharge figures as a result.

Also worth a look in the VRM diagnostics — filter by "Battery SOC" source and see what's actually feeding that number. Sometimes it's the MultiPlus-II doing the calculating rather than the BMS, which will throw things out considerably once you've had a few partial cycles.

What firmware are you running on the Cerbo? There were some DVCC-related fixes in recent releases that made a noticeable difference for me.

ExChippie72 | 312 posts

@BayPete Had almost identical grief on the boat last winter — MultiPlus-II convinced itself the bank was charging when we were clearly pulling from it. Inverter humming away, lights on, and VRM showing positive current. Maddening.

What fixed it for me was setting the CCGX battery monitor explicitly to the MultiPlus rather than leaving it on Automatic. Victron's auto-detection gets confused when the BMS is also pushing SOC data simultaneously — essentially two sources arguing over who's right, and neither winning.

Go into Settings → System setup → Battery monitor and force it manually. If you're also seeing the SOC drift wildly between 40-60%, that's the telltale sign it's flipping between data sources mid-session.

Worth ruling that out before diving deeper into the DVCC rabbit hole @Renogy_Nerd mentioned — that path gets dark quickly.