Anyone else notice their inverter fan kicking in more during this warm spell?

My Victron Multiplus has been going like a hairdryer in a sauna since Tuesday — fairly sure it's generating more heat than my actual solar panels right now.

Bumped my battery bank ventilation after noticing the Fogstar cells creeping up to temperatures I wasn't happy with. Simple fix but wish I'd done it sooner honestly.

Few things worth checking if you're in the same boat:

• Fan intake clearance — mine had about 3cm against the wall, moved it to 10cm and temps dropped noticeably
• Ambient monitoring — chucked a cheap sensor in the inverter cupboard, eye-opening stuff
• Load scheduling — running the washing machine at 07:00 before the shed gets properly warm has helped massively

The irony of getting loads of free solar generation but having to throttle usage because everything's overheating is not lost on me whatsoever. Peak British summer energy crisis right there — too much sun, still somehow struggling.

Anyone running active cooling in their inverter space? Considered a small 12v extraction fan pulling hot air out but not sure if it's overkill or genuinely necessary for a setup my size. Curious what ambient temps others are seeing before their units start complaining.

@TID_Electric yeah the Multiplus fans are notoriously temperature-sensitive — Victron set the thresholds fairly conservatively so they spin up well before there's any actual thermal issue. Annoying but probably the right call.

Worth checking what temp it's actually hitting via VictronConnect before you go drilling more ventilation holes. Mine sits in the back of my static and I was convinced it was overheating until I checked — turned out it was 42°C internal, well within spec, just loud about it.

One thing that does make a real difference is airflow around the unit rather than just near the batteries. If it's recessed into a cupboard with no clearance above it you'll see the fans working constantly regardless of ambient temp.

What's your load profile like during the day? Running heavy AC loads will push it harder than the weather alone.

Worth checking your ambient temp in the inverter location too — I've got a cheap thermometer stuck on the wall next to mine and it was reading 34°C in the garage on Wednesday afternoon. Even if the inverter itself is fine, sustained high ambient temps will push it into derating territory before the fans even tell the full story.

@TID_Electric have you checked VRM or your CCGX to see if it's actually throttling output? Sometimes the fan noise is alarming but the unit is coping fine — other times you're quietly losing 20-30% capacity without realising. Might be worth shifting it somewhere with better airflow if you can, even temporarily. A small USB fan blowing across the vents made a noticeable difference for mine last summer.

@TID_Electric same story at my cabin this week — Multiplus II been running noticeably warmer than usual. One thing worth investigating beyond ambient temp is your load profile during peak heat hours. I found my inverter was working hardest mid-afternoon (running EV charging alongside the usual cabin loads) precisely when ambient was already 35°C+ inside the enclosure. Staggering the EV charge session to early morning made a noticeable difference to fan activity.

Also worth pulling up the VRM portal if you're on Cerbo — you can graph internal temperature against fan speed and correlate it with load spikes. Made it much easier to identify the culprit rather than guessing. Victron's derating curve kicks in around 40°C internal, so if you're hitting that threshold regularly you'll start seeing output clipping before the fan even solves the problem.

@TID_Electric ha, mine's been doing exactly the same — sounded like it was trying to take off on Tuesday afternoon! One thing I'd add that nobody's mentioned yet: check whether anything's crept up against the unit over the summer. I found a load of spiders had built up a fair bit of fluff around my ventilation slots over winter, which was definitely not helping airflow. Gave it a careful hoover and the temperatures dropped noticeably. Also worth double-checking your load profile during the hottest part of the day — if you're running high-draw appliances when ambient temps are already peaking, you're really stacking the odds against it. I try to shift things like washing machine cycles to early morning now during warm spells. Nothing wrong with the unit itself usually, just needs a bit of seasonal management.