Enphase envoy communiceert maar meetwaardes komen niet overeen

Bit of an odd one for the Batteries & BMS board but felt it fit better here than general chat...

So I've been wrestling with something similar in my garden office setup. Running a Victron Multiplus with a Cerbo GX, a small Enphase micro-inverter array on the roof, and a 15kWh pack using a JK BMS. Everything communicates fine on paper — VRM shows the Enphase data coming through — but the numbers just don't add up.

My Enphase app reckons I'm generating X, the Cerbo shows something noticeably different. Not talking rounding errors either, we're talking 8-12% discrepancy at times.

A few things I've been poking at:

• CT clamp placement — mine was borderline dodgy at install
• Polling intervals not syncing properly between the Envoy and the GX device
• Whether the Enphase Envoy local API is actually reporting the same figures as the cloud app (spoiler: sometimes it isn't)

The JK BMS side of things has been rock solid for me tbh — Fogstar cells, no drama there. The headaches are all upstream with the monitoring stack.

Anyone else running Enphase alongside Victron kit in a UK setup? Curious whether this is a known gremlin or something specific to my configuration. I suspect it's the Envoy local vs cloud discrepancy but I'd love someone to either confirm that or tell me I'm barking up the wrong tree entirely.

What's your monitoring setup looking like?

Hang on, the thread title's in Dutch? Bit lost there 😅

Anyway @CotswoldExplorer yeah the Victron Multi can be a right pain for mismatched readings. Had similar on my shepherd's hut build — turned out my Cerbo GX wasn't pulling the right data from the BMV-712 because I'd set the battery capacity wrong in VictronConnect. Completely throws the SOC calculations off.

Worth double-checking:

• Battery capacity setting matches your actual bank
• Peukert exponent if you're on LiFePO4 (should be closer to 1.05)
• Tail current set properly

Fogstar Drift cells here and once I sorted those settings the readings lined up almost perfectly. Might not be your exact issue but seems worth ruling out before digging deeper.

@DalesCruiser yeah the Dutch title threw me too — suspect a copy-paste gone wrong from a different forum.

@CotswoldExplorer this is worth nailing down properly. The Victron Multi's internal current sensor and whatever your BMS is reporting will almost always diverge slightly due to shunt placement and measurement timing differences. Key questions:

• Where's your shunt physically located relative to the BMS sense wires?
• Are you using a Victron SmartShunt or relying solely on the Multi's built-in measurement?

In my cabin setup I had a consistent 4–6A discrepancy until I made the SmartShunt the single source of truth and piped everything through VE.Direct into Cerbo GX. Once the BMS was configured to trust the external shunt rather than its own coulomb counter, figures lined up within 1A.

What BMS are you actually running? That'll determine whether this is even configurable.

@CotswoldExplorer yeah the Dutch title is a bit of a head-scratcher but I get the gist of what you're after.

Worth noting that the Enphase Envoy and Victron worlds don't really talk to each other natively — they're fundamentally separate ecosystems. If you're seeing measurement discrepancies, it's almost certainly because you're reading consumption from two different points in the circuit rather than an actual fault.

On my cabin setup I had similar confusion until I properly mapped out where each CT clamp was sitting relative to the inverter and grid connection. The numbers only made sense once I drew it out on paper.

Have you checked your VRM portal readings against what the Envoy app shows? That usually helps isolate whether it's a comms issue or just a measurement reference point mismatch.

Jumping in as someone also running a tiny house setup — I've had similar head-scratching moments with Victron readings not matching up.

One thing nobody's mentioned yet: are you checking whether your Venus OS firmware is current? I had wildly inconsistent readings on my Multiplus until I updated through the VRM portal. Night and day difference.

Also worth double-checking your CT clamp positioning if you're monitoring grid input — even being slightly off can throw the figures out significantly.

@DODQueen makes a fair point though, what exactly are the values that aren't matching? Grid vs battery readout, or something else entirely? Knowing which figures are disagreeing would help narrow it down — there are a few different culprits depending on where the discrepancy shows up in the system.