SmartSolar100/30_cooling_charge_levels

Mine ran so hot last summer I could've fried a full English on it — anyone else playing the guessing game with Victron's actual thermal headroom requirements?

The manual says 10cm above and below for the 100/30, but that feels like it was written by someone who's never tried cramming one into a narrowboat battery compartment. I've got mine wall-mounted in a fairly tight wooden enclosure and during a proper sunny July day it was throttling back charge current noticeably — VictronConnect showed the thermal derating kicking in around 2pm like clockwork.

Few things I've found that actually help:

• Orientation matters more than clearance — vertical mounting with the fins running the right way makes a real difference
• Keep it away from your batteries — obvious maybe, but ambient temp in a sealed box will murder your headroom
• Light-coloured enclosures if you're outside — my mate swapped his black plastic box for a white one and dropped idle temps noticeably

Currently wondering whether adding a small 12v fan on a temperature relay would be overkill or genuinely worthwhile. The Victron itself handles the throttling gracefully enough, but I'd rather it was charging at full whack during the limited decent sunshine we get up here rather than babysitting itself.

Anyone running theirs in a really confined space and found a practical solution that doesn't involve ripping out the whole install? Curious what clearances people are actually getting away with versus what the manual insists on — feels like one of those specs that has a fair bit of real-world wiggle room depending on your setup.

@Brummie84 I had the exact same drama with mine bolted inside the motorhome's rear cupboard last spring — thought I'd done everything right until I noticed it throttling back on a cracking sunny afternoon.

The 10cm spec in the manual is genuinely the minimum — real-world breathing room is a different story. What nobody mentions is that the SmartSolar runs its thermal derating algorithm quite aggressively once the internal temp sensor climbs past around 40°C ambient. You'll see charge current quietly creeping down in the VictronConnect app if you watch it carefully.

What actually sorted mine was mounting it vertically on an external locker wall with a small 80mm fan on a temperature-triggered relay. Dropped operating temps by nearly 15°C on a warm day. The difference in harvest was noticeable immediately.

@Brummie84 Victron's "10cm" suggestion is adorable — mine needs closer to 15cm clearance and forced airflow before it stops throttling on a decent Welsh summer day, which admittedly isn't often.

The SmartSolar 100/30 will derate charge current automatically when it hits ~80°C internally, so you're not frying anything, just wasting solar yield whilst your fridge slowly gives up.

Stick a cheap 12V Noctua-equivalent fan on a temperature controller (Inkbird ITC-308 does nicely) set to kick in around 35°C ambient — transformed mine in the static caravan install. Also worth checking the VictronConnect app history tab; it logs thermal derating events so you can actually see how much you're losing rather than guessing.

@Brummie84 mine lives in the van's wet locker and I basically gave it its own little desk fan on a thermostat — Victron MPPT running hot enough to derate is just money evaporating silently while you're sat in a layby feeling smug about your solar setup.

@Rob1963 yeah the 10cm thing is optimistic at best 😄

Mine's wall-mounted in the garage with about 20cm clearance all round and it still gets properly warm on a cracking summer day when the panels are pushing full whack. Dropped absorption voltage slightly during July heatwave and it made a noticeable difference to temps — worth trying before going the fan route.

Also worth checking the charge current limit if you're in a tight space — I've got a Fogstar 200Ah lithium and throttling back to 20A from 30A dropped controller temps considerably with minimal real-world impact on charge times.

Victron Connect thermal derating kicks in automatically but by then you're already losing efficiency, better to get ahead of it.

@Brummie84 mine's bolted to a timber bulkhead in the engine bay of a 38ft narrowboat — so I've lived this particular nightmare.

What actually sorted it for me was paying attention to orientation more than raw clearance. The heat fins run vertically on the MPPT, so mounting it portrait with good vertical airspace lets convection do the heavy lifting. Even 12cm of clear vertical chimney made a noticeable difference on the Victron app's reported temp versus when I had it slightly canted.

Also worth logging charge current against ambient temp through the VRM portal if you're not already — I could see mine throttling back on 30°C afternoons well before it threw any warnings. Once I spotted the pattern I repositioned it and recovered maybe 8-10% of afternoon harvest. Small gains, but on a boat every watt matters.