Victron MPPT 100/30 running warm — normal or should I be worried?

Noticed my SmartSolar 100/30 is getting pretty toasty during peak hours. Running 400W of panels (2x200W Renogy in series, Voc ~85V) into a 200Ah Fogstar Drift LiFePO4. Ambient in the van is probably 28–32°C at the moment given the weather we've had.

Touching the heatsink fins it's uncomfortable to hold — I'd guess 55–60°C surface temp, maybe more. Victron's spec sheet says max operating is 40°C ambient with derating above that, so I suspect it's just throttling back slightly rather than anything catastrophic. The BT app isn't showing any thermal warnings and output looks normal.

Currently it's mounted on the rear internal wall with maybe 50mm clearance above and below. No fan, no active cooling. I've seen people recommend at least 100mm of free air around the unit — wondering if that's actually making a meaningful difference for anyone, or whether it's just theoretical.

Has anyone measured actual temperature reduction from improving airflow or adding a small 12V fan nearby? Thinking of relocating it closer to an external vent but that's a fair bit of work before I commit to it.

Hey @T6Solar, these do run warm — totally normal for a unit pushing decent current on a hot day. The 100/30 will throttle itself (thermal derating) before anything bad happens, so Victron's built the protection in. That said, worth making sure it's not tucked behind insulation or in a sealed cupboard with no airflow. Even just mounting it on an exterior wall panel or adding a small 12V fan nearby makes a noticeable difference.

One thing to check in VictronConnect — you can see the actual charge current and whether it's derating. If it's regularly pulling back on a warm day, improving ventilation would be worthwhile. With 400W feeding into a healthy LiFePO4 you're probably seeing close to the full 30A output, which'll generate a fair bit of heat. Nothing to panic about though! 🙂

Good shout from @Jonno88 on the throttling. One thing worth adding — make sure the unit has decent airflow around it. In a van install especially, people often mount these in tight spots or against insulation and wonder why it's cooking. Victron recommend mounting on a metal surface if possible so heat can conduct away efficiently. The 100/30 is rated up to 40°C ambient before it starts dethrottling, so if your van interior is pushing beyond that on a sunny day, you'll naturally see some power reduction. Not harmful, just the protection doing its job. You can monitor charge current in the VictronConnect app to see if it's actually curtailing output. With 400W of panels on a 30A controller you're already near the ceiling anyway, so a bit of thermal headroom in the mounting location goes a long way. 👍

Great points from @Jonno88 and @AGM_Guy already. One thing I'd add — with a LiFePO4 like the Fogstar Drift, make sure your charge profile is set correctly in VictronConnect. The default settings are often tuned for AGM, and incorrect absorption voltage can cause the MPPT to work harder than necessary, generating extra heat. Pop it into Lithium mode or use a custom profile (absorption around 14.2V, float 13.5V is a common starting point for LiFePO4). Also worth checking your wiring gauge between the controller and battery — undersized cable creates resistance which can push more heat into the system overall. The 100/30 has built-in thermal protection so it'll look after itself, but optimising the setup means it runs cooler and more efficiently long-term. What temperatures are you actually seeing on the unit itself?

Good coverage from the others already. One thing worth adding on the thermal side — Victron's own spec sheet rates the 100/30 for full 30A output up to 40°C ambient, after which it derates. If your van interior is already sitting at, say, 35°C and the unit is mounted in a poorly ventilated cabinet, you could be hitting that threshold sooner than expected.

Worth pulling up VictronConnect and checking the absorption/float current logs over a few days — if you're consistently seeing output drop during peak solar hours, that's your derate kicking in rather than the battery simply being full. Two different problems with different solutions.

Mounting orientation matters too; the fins should be vertical so convection actually works. Horizontal mounting is surprisingly common in van builds and kills passive cooling efficiency.