ESS phase balancing issue: buying and selling electricity at the same time

Had something similar drive me absolutely mental last winter with my ESS setup in the motorhome conversion I'm doing (yeah I know, three-phase in a motorhome is overkill, don't @ me).

But more relevant for the tiny house — running a Victron Multiplus-II and noticed the grid balancing was doing something daft. Solar surplus was being pushed out unevenly across phases, so I was simultaneously exporting on L1 and importing on L2/L3. Net metering on my supplier's end doesn't care, but I'm still getting charged import rates on those legs. Essentially paying for electricity while giving it away for free. Brilliant.

I think the issue is how the DESS scheduling interacts with phase compensation settings. There's a ESS phase compensation option buried in VEConfigure that I'd not touched. Worth checking if yours is set to individual rather than total — that might be the root cause for some of you.

A few things I'd try:

• Check your phase compensation setting in VEConfigure
• Look at whether your CT clamps are reading correctly on each phase
• Fogstar/Victron community forums had a thread on this, worth digging up

Still not 100% sorted on mine if I'm honest. The DESS scheduling feels like it's doing its own thing sometimes regardless of what I configure.

Anyone else hit this? Particularly curious if people with proper domestic installs (not bodged tiny house situations like mine) are seeing it too. Is this a firmware thing or am I just configuring something wrong?

@OffGridMax ha, three-phase in a motorhome is absolutely sending me 😂 No judgement though — I've got a setup on the boat that makes people raise an eyebrow too.

The buying-and-selling-simultaneously issue is usually the ESS assistant getting confused about which phase is "responsible" for the grid setpoint. Worth checking your AC input current limit settings — I had mine fighting itself because the Victron ESS assistant was trying to balance across phases whilst the MPPT was dumping surplus into one leg.

In VictronConnect, dig into the ESS minimum SOC and grid setpoint values. Sometimes just nudging the setpoint from 0W to something like 50W stops that weird simultaneous import/export dance.

What firmware are you running on the GX device? That made a massive difference for me last time this cropped up.

@OffGridMax curious what grid code you're running on the Victron — had this exact buying/selling simultaneously issue on my home setup last year. Turned out my ESS assistant was set to optimise without BatteryLife which caused weird phase imbalance behaviour at low SOC. Switching to keep batteries charged temporarily while I sorted the grid setpoint fixed it.

Worth checking your AC input current limit too — if it's set too low the system starts doing odd things trying to balance across phases whilst simultaneously deciding it needs to export. Sounds like what you're describing.

What firmware are you on? There were some ESS phase compensation bugs in older versions that Victron quietly fixed around v2.90 on the CCGX/Cerbo.

@MidlandsNomad the grid code question is the key one here. I spent a genuinely embarrassing amount of time staring at VEConfigure before I twigged that my AC input current limits were set asymmetrically across phases — the Quattro was basically arguing with itself about what to export and import simultaneously.

Worth checking your ESS Assistant configuration too, specifically the minimum SOC and grid setpoint values. Mine was set to 0W grid setpoint which sounds right but actually causes this phantom trading behaviour on unbalanced loads.

Had the same head-scratching moment on my barn setup last February. Ended up diving deep into the Victron Community forums at about 11pm with a cup of tea going cold. The fix was almost insultingly simple once I found it.

What firmware are you both running on the CCGX/Cerbo?

@ExFarmer90 my tiny house Victron did the same thing — turns out it was less "intelligent energy management" and more "spending my money in both directions simultaneously like a drunk me at a funfair."

@PhilJackson absolutely nailed it with the "software having an existential crisis" description 😄

Worth adding the actual fix though: in VEConfigure, check your AC Input current limit per phase versus your ESS minimum SOC interaction. What's often happening is the phase compensation algorithm is trying to balance reactive power across phases while simultaneously honouring the feed-in limitation — so you end up with L1 selling whilst L2/L3 are buying to compensate.

The fix that worked on my cabin setup:

• Set phase compensation to "total of all phases" rather than per-phase
• Check ESS > Grid feed-in > Limit system feed-in is actually enabled
• Verify your grid code matches your DNO requirements (G98 vs G99 matters here)

The "total of all phases" setting essentially lets Victron net off the imbalance internally before deciding whether to trade with the grid. Night and day difference.