230V, 3phase Delta Load

Bit of an unusual one this, but curious if anyone's tackled a genuine 3-phase delta load off-grid without resorting to transformers.

Context for me: looking at potentially powering some older 3-phase workshop equipment on the boat (yes, I know — don't ask how that conversation started). The kit in question wants 230V line-to-line in a delta configuration, which is where it gets awkward with Victron's multi-unit 3-phase setups.

The standard Quattro 3-phase arrangement gives you 400V line-to-line with 230V phase-to-neutral — i.e., standard European star/wye. That's fine for most things, but a true delta load expecting 230V L-L is a different beast entirely.

From what I can work out, your options are roughly:

• Step-down transformer on each phase (messy, lossy, expensive)
• Single-phase workaround if the load can be rewired
• Specialist inverter that actually outputs lower line-to-line voltage natively

Has anyone actually done this cleanly? I've seen some discussion about using three smaller single-phase inverters in an open-delta arrangement but I'm not convinced that's stable under varying loads.

Fogstar and similar battery suppliers aren't the issue here — it's purely the AC output side. Victron's own documentation goes a bit quiet on this specific scenario.

Would be interested to hear from anyone who's powered genuine 3-phase delta machinery off a battery bank — narrowboat, off-grid building, workshop, whatever the setup. What did you actually end up doing?

@RKE_Builds ran into something similar when I was scoping out power for a workshop next to my static. Three proper Victron Quattros stacked in 3-phase config is the textbook answer, but the cost is eye-watering and delta specifically is a headache because most consumer-grade inverters output star (neutral referenced).

The honest reality: delta loads expect line-to-line voltage, so your 230V phase-to-phase becomes your problem. You're either re-winding that motor for star operation, fitting a VFD to bridge the gap, or yes, transformer.

VFD route is what I'd actually do. Decent inverter-duty VFD, single-phase 230V input, 3-phase output to your motor. Cheaper than three Quattros and it handles older motors gently on startup too — massive bonus with vintage equipment.

What's the actual load? Motor size matters enormously here before anyone gives you sensible numbers.

Three Victron Quattros stacked in three-phase config can do it natively — just bear in mind delta loads create neutral current issues that a wye inverter stack handles differently, so you'll want to verify your load's neutral requirements before assuming it'll play nicely.

If your older machinery is true delta (no neutral needed), three-phase Victron stacking is actually cleaner than you'd think — the units negotiate phase relationships automatically via the VE.Bus interconnect, and I've seen it done rock-solidly for workshop compressors running continuous duty.

Key pedant point: confirm whether your load is delta-connected internally or just happens to be three-phase — many older motors are delta/star switchable at the terminal block, which changes your approach entirely.

Budget reality check: you're looking at three inverter/chargers plus a beefy 48V battery bank — Fogstar Drift cells if you're building your own.

@RKE_Builds worth flagging that genuine delta loads (no neutral conductor) are actually easier to handle with three stacked Quattros than wye loads in some respects — the neutral current issue @OldSailor mentions disappears entirely since delta never references neutral.

The gotcha is phase balancing. Delta loads draw line-to-line, so if your load isn't perfectly symmetrical across all three phases, you'll see unequal current distribution and the Victron units will fight each other trying to compensate. VE.Bus comms handle this reasonably well but it's not perfect.

Practically speaking: make sure you're configuring via VEConfigure with three-phase delta selected explicitly, not wye. The firmware distinction matters. Also verify your Quattro firmware is identical across all three units — mismatched versions cause sync instability under load transients.

What's the actual load — motor-driven equipment? Knowing the kVA and power factor would help narrow down whether you need oversizing on the inverter side.

@OldSailor raises a good point about neutral current — worth expanding on that. With a true delta load, you've got no neutral path at all, which actually simplifies your Victron three-phase stack config considerably. The tricky bit I found on my boat-to-cabin conversion project was balancing the phases properly; unbalanced delta loads will hammer one inverter harder than the others, and the Quattros will throttle back to protect themselves. Check your motor nameplates carefully — older 3-phase kit often has significant power factor variance between phases depending on load state. I'd strongly recommend enabling the "three-phase compensation" setting in VE.Configure and monitoring individual phase currents via Cerbo GX before committing to a permanent install. Fogstar cells paired with three Quattros can handle the inrush surprisingly well, but get your battery C-rating right first.