Victron ESS und Wallbox, wo ist der Flaschenhals?

Been meaning to post about this for a while, actually.

Running a Victron ESS setup on my static caravan plot — three Multiplus-II 48/5000s in a three-phase config, backed by a modest bank of Pylontech US3000Cs, with around 10kWp of panels feeding through a pair of SmartSolars. Works beautifully most of the time.

The wrinkle came when I added a Type 2 EV charger — nothing fancy, a 7kW Rolec unit. What I noticed was the system struggling to decide where the bottleneck actually was during evening charging sessions. Was it the inverters hitting their combined output ceiling? The Pylontechs throttling discharge current via the BMS? Or the ESS algorithm itself being overly cautious about grid export limits I'd set?

Took a good week of staring at VRM dashboards before I started to piece it together. The BMS was actually the quiet villain — the US3000Cs communicate a max discharge current that the Multis respect absolutely, and when the battery SOC dips below about 30%, that ceiling drops sharply.

What I'd love to know from others here:

• Has anyone mapped out exactly where their ESS loses capacity under heavy AC loads like a wallbox?
• Does adding more battery strings genuinely shift that bottleneck, or just move it elsewhere?
• Any experience with Fogstar or alternative lithium banks that give the BMS a bit more generosity at lower SOC?

Feels like this is one of those things where the system is technically working correctly, it's just the interaction between components that catches you out. Curious whether anyone's done a proper monitoring exercise

@DerekDixon mate the thread title's in German but your post is in English — your ESS setup isn't the only thing having an identity crisis 😄

But yeah, three-phase Multiplus-II is a proper setup for a static caravan plot — most of us are just happy if our single unit doesn't fall over when the kettle kicks in!

@WonkySkipper multilingual ESS — must've set the grid code to "confused European" by mistake.

@DerekDixon your bottleneck's almost certainly the DC bus if you're running three Multiplus-IIs without a proper Lynx Distributor keeping things tidy — been there with my own setup and the Fogstar Drift cells were getting blamed for everything until I sorted the busbars. What BMS are you running? Because a JK or Daly throttling charge current under load will make your wallbox feel like it's charging through a wet piece of string.

@DerekDixon your post got cut off harder than my Fogstar cells in -3°C last February — we're all just sat here waiting for the actual question like a Victron MPPT waiting for sunrise.

@DerekDixon meanwhile the rest of us are doing our own ESS — Extended Suspense Sitting — waiting for you to finish that sentence about your battery bank.

At least your Multiplus-IIs are configured correctly. Your post, on the other hand, appears to be running on a 50% SoC with no absorption phase in sight