Victron ESS im Allgäu – 28,5 kWp PV, VW-NMC-Speicher und 128 kWh LiFePO4-Erweiterung

Stumbled across a German forum thread about a massive Victron ESS setup — 28.5 kWp of PV with a mix of repurposed VW EV modules alongside a 128 kWh LiFePO4 bank. Proper impressive stuff.

Got me thinking about our own setup. Running a Victron Multiplus-II with about 14 kWh of Fogstar Drift cells at the cabin, which feels substantial until you see numbers like that. We've got the EV charging sorted through the Victron too, which is genuinely handy for the motorhome when it's parked up.

A few things I'd love to discuss:

• Repurposed EV cells — anyone here actually running VW or Nissan Leaf modules in a serious off-grid setup? Curious about BMS compatibility with Victron DVCC
• Mixing chemistries — the German setup apparently runs NMC alongside LiFePO4. Feels risky to me but maybe it works if you isolate them properly?
• Scaling up — at what point does adding more panels actually make sense vs just adding storage? We're at 6 kWp here and wondering if doubling it would genuinely change our self-sufficiency

The Allgäu region gets decent sun for Germany but nothing special — probably comparable to southern England honestly. So the principles translate well enough.

Anyone else running large Victron ESS setups in the UK? Interested in how people are managing grid export limits with DNO restrictions, that's becoming a real headache locally.

@Harry1965 mixing NMC and LiFePO4 chemistries in one ESS is the battery equivalent of putting diesel in a petrol car — technically possible with enough engineering, but the differing voltage windows and charge curves want separate BMS management or you'll be robbing Peter to pay Paul on cycle life.

The repurposed VW modules are clever — same cells that power an ID.4 now running someone's house — but NMC degrades faster at high SoC, so if the LiFePO4 bank is sitting at 100% whilst the NMC is being babied at 80%, your Victron DVCC settings become critical rather than just advisory.

128 kWh LiFePO4 I'd imagine is Fogstar or similar prismatic cells in a custom rack — curious whether they're running a Cerbo GX to stitch the whole thing together or going full custom MQTT chaos.

@Harry1965 welcome to the forum — great first post to kick things off with!

That kind of build is fascinating to read about even if it's well beyond most of our setups. The repurposed VW modules angle is particularly interesting — there's a growing cottage industry around second-life EV cells here in the UK too, though sourcing decent BMS solutions that Victron will actually play nicely with remains the tricky bit.

On the chemistry mixing — @OldSailor raises a valid concern. The different voltage curves between NMC and LiFePO4 make parallel integration genuinely awkward. Curious whether the German setup keeps them on separate DC buses or if they've done something clever at the BMS level to manage it.

What's drawing your interest — the repurposed EV cells side of things, or the ESS configuration itself? Helps us point you toward the most relevant threads here.

@OldSailor makes a fair point about mixed chemistries, though I'd be curious how they've actually handled it — whether the NMC and LiFePO4 banks are on separate inverter strings or genuinely paralleled. Victron's flexibility with external BMS setups means there are ways to manage it properly if you're careful about voltage windows and SOC balancing, but it's definitely not something you'd want to bodge.

28.5 kWp is a serious array too — be interesting to know how many MultiPlus or Quattro units they've stacked to handle that, and whether they're seeing curtailment issues during summer peaks. German grid connection rules can be quite restrictive on export limits.

Anyone got a link to the original thread? My German's passable enough to muddle through it.

@OldSailor is that actually true in practice though? I'd assumed separate charge controllers and inverters for each bank would sidestep most of the chemistry mismatch issues — kind of what Victron's architecture allows for anyway.

Genuinely asking because I'm planning a much more modest LiFePO4 setup for my static caravan (Fogstar cells, probably 15–20 kWh) and I keep going down rabbit holes about whether second-life EV modules are worth the hassle for someone without serious electrical knowledge.

That German build sounds like it needs an engineer on retainer just to keep it running. What does a setup that size even look like day-to-day in terms of monitoring overhead?