Komisches Solarregler verhalten bei einer Installation

Anyone else had their Victron SmartSolar start acting like it's on a go-slow strike when you've got multiple units running in parallel?

Running three MPPT controllers across my shepherd's hut and boat setup — same kit, same config, same firmware — and one installation behaves impeccably whilst the other one basically decides it fancies a lie-in and underperforms by about 30% most mornings before noon.

The well-behaved setup is:

• 3x SmartSolar 100/30
• Fogstar Drift LiFePO4 bank
• All networked via VE.Smart

The awkward one mirrors it almost exactly, but seems to lose the plot whenever cloud cover rolls in — which, this being the Welsh borders, is approximately always.

My suspicion is it's something to do with how the MPPT algorithms are talking to each other under dynamic irradiance conditions, but honestly it could just as easily be a dodgy VE.Direct cable sulking.

Has anyone successfully run a multi-MPPT setup where one installation was rock solid and a near-identical one was a complete drama queen? Particularly interested if anyone's mixed Victron with a Fronius or similar grid-tie hybrid — the original thread that got me thinking about this was running that combo and I wonder if there's some handshaking weirdness going on between different manufacturers' charge logic.

Drop your configs below — curious whether this is a networking issue, a shading/string config problem, or just one of those things where off-grid energy decides to be inexplicably weird on a Tuesday.

@BorderWanderer classic Victron parallel drama — make sure all three MPPTs are networked via VE.Smart otherwise they're basically three blokes at a tug-of-war pulling in different directions 🪢

Key things to check:

• Sync charging enabled across all units in VictronConnect
• All running identical firmware (mismatched versions causes exactly this go-slow behaviour)
• Shared voltage sense — one unit nominated as the network master

Had the same chaos in my shepherds hut setup before I sorted the VE.Smart network properly — went from 60% efficiency to near perfect harvest overnight, like waking a sleeping giant.

Also worth checking your battery temperature sensor is only assigned to one controller, not competing across all three — that'll confuse the absorption stage something rotten.

@BoatPaddy has covered the VE.Smart networking side, so I won't repeat that.

One thing worth checking that catches people out — if you're running multiple SmartSolars, they all need to have identical absorption and float voltage settings, otherwise whichever unit hits its target first essentially starts throttling back while the others are still pushing hard. Looks like a "go-slow" but it's actually the units fighting each other.

Also worth confirming your battery temperature compensation is either enabled consistently across all three or disabled across all three. Mixed settings here causes odd charging behaviour that's really hard to diagnose.

Had something similar on my static caravan setup with two MPPTs before I realised one had drifted settings after a firmware update. VictronConnect makes it straightforward to compare — just connect to each controller individually and screenshot the settings side by side.

Good points from @BoatJason and @BoatPaddy already.

One thing I'd add — check your battery voltage sense setup. If each MPPT is measuring voltage at its own terminals rather than at the battery, you'll get three controllers arguing over what the actual voltage is, and they'll all throttle back thinking absorption is done when it isn't.

Victron's own recommendation is to use shared voltage sense via VE.Smart network and ideally run a dedicated sense wire to the battery terminals if you're seeing significant cable voltage drop.

Also worth checking firmware on all three is identical — mixed firmware versions in a parallel setup causes weird throttling behaviour that looks exactly like what you're describing. Update them all via VictronConnect and see if that settles it down.

@BorderWanderer worth asking the obvious — have you actually confirmed all three are running the same firmware version?

Victron parallel setups can get genuinely weird when units are on different firmware. They'll technically talk to each other via VE.Smart but the synchronisation behaviour differs between versions and you end up with one unit essentially going rogue.

Had exactly this on my static van when I added a third SmartSolar — two units were on v1.59, one had auto-updated to v1.61 and the charging coordination was all over the place.

VictronConnect shows firmware version on the device info screen. If they're mismatched, update them all through the app. It's not guaranteed to fix your problem but it's a five-minute check that rules out a fairly common culprit before you start chasing wiring gremlins.