Issue Code #25

Got the dreaded Error 25 flashing on my Victron EasySolar-II 48/5000 last Tuesday — right in the middle of charging the shepherd's hut battery bank, naturally.

For those who don't know, Error 25 is apparently a firmware or internal communication fault, though Victron's documentation on it is about as clear as a Scottish haar. Ended up down a rabbit hole on the VRM portal for an hour before I even confirmed what the code meant.

Mine resolved itself after a hard reset, but it's got me thinking — has anyone else seen this pop up when running parallel or combined Victron units together? I've read a few vague mentions of it occurring when a Phoenix Inverter is paired alongside an EasySolar in the same system, particularly if one unit's firmware is lagging behind the other.

A few things I'd be curious about from folks with similar setups:

• Did yours self-clear, or did it require a full reconfiguration in VictronConnect / Venus OS?
• Anyone managed to replicate it consistently enough to identify a trigger?
• Is it worth updating Venus OS proactively even if things seem stable, or is "if it ain't broke" the sensible British approach here?

Running Fogstar Drift lithium on the battery side if that's relevant — though I suspect this is purely a comms issue between inverter units rather than anything BMS-related.

Would be good to pool some real-world experience rather than just refreshing the Victron Community forums hoping someone cleverer than me has posted.

@SaltyTrekker Error 25 is your EasySolar throwing a fan fault — basically the cooling fan's either seized, disconnected, or clogged with enough fluff to knit a jumper! 🧶

Had the exact same drama with my shepherd's hut setup — cracked it open and found a heroic quantity of dust bunnies staging a sit-in over the fan blades.

Quick checklist:

• Power down completely (AC + DC)
• Remove the cover and give the fan a gentle spin by hand — should rotate freely
• Blast it with compressed air
• Check the fan connector hasn't vibrated loose

If the fan's actually dead, Victron replacement fans are readily available and it's a straightforward swap — don't ignore it though, thermal shutdown will follow sharpish and that's a much worse Tuesday than a flashing error code.

@SaltyTrekker Worth checking whether dust or debris has packed into the fan housing before assuming the worst — my garden office unit threw the same code last autumn and it turned out a moth had got itself wedged in the impeller. Embarrassingly simple fix.

If cleaning doesn't resolve it, Victron's fan assembly is user-replaceable without voiding warranty provided you're competent with a screwdriver and document everything. Source the part through Bimble or Victron's UK distributor network rather than generic eBay equivalents — the fan spec matters for thermal management at full load.

One thing @BoatPaddy likely covered: run the unit with the casing off briefly (safely, mind) and watch whether the fan spins at all on startup. Seized versus disconnected versus firmware-controlled fault are three very different diagnoses, and conflating them wastes time.

@BoatPaddy is right about the fan, but I'd add — before you go poking around inside, check the ambient temperature where your EasySolar is mounted. I had a similar scare with mine in the hut last summer; turned out the unit was installed in a poorly ventilated cupboard and the thermal shutdown was masking itself as a fan fault.

Also worth pulling the VE.Bus error log via VictronConnect before you disassemble anything. Saves you stripping it down only to find it's a software flag rather than a mechanical failure.

If it is the fan itself, genuine Victron replacement fans aren't cheap but they're available through Bimble Solar or Victron UK dealers — I'd avoid the cheap eBay equivalents on a 5kW unit. Not worth the risk.

Had this exact saga in my van conversion last winter — once you've ruled out the obvious (dust, temp, disconnected fan), grab a multimeter and check the fan's supply voltage while the unit's under load; if the voltage is there but the fan isn't spinning, it's the fan itself rather than the controller board, which is the cheaper outcome.

Victron's replacement fans are surprisingly affordable and the swap takes about 20 minutes if you're methodical about it — just photograph everything before you touch it.

Really interesting thread — I've been half-expecting this on my cabin setup so watching closely.

One thing nobody's mentioned yet: have you checked whether the Cerbo GX (if you're running one) is logging the exact timestamp and ambient temp readings when the fault triggers? On mine I can pull up the VRM portal history and see whether the error correlates with peak solar input periods rather than high ambient temps — which would point toward a load/thermal management issue rather than a faulty fan per se.

Worth cross-referencing the error timing against your MPPT charge curves. If the fault consistently appears when bulk charging hits maximum current, the thermal protection might be responding to genuine internal heat rather than a sensor fault.

Has Victron's own Remote Diagnostics via VRM flagged anything additional beyond the raw error code?