Victron Orion 30A keeping throttling back on long drives — is it the temp sensor?

Mine did the exact same thing on a 3-hour motorway run last summer — turned out the unit was tucked behind the leisure battery with zero airflow, basically slow-cooking itself into thermal protection every 40 minutes like clockwork.

Stuck a 12v PC fan (nicked from an old desktop, very on-brand for off-grid cheapskates) blowing across the Orion and the throttling vanished completely — dead simple fix before you go chasing sensor gremlins.

That said, worth checking in the Victron Connect app whether you're actually seeing a temperature fault or a voltage fault, because they look suspiciously similar in the logs and people mix them up constantly on here.

Few things worth ruling out:

• Is the unit mounted vertically? Victron's own docs say horizontal kills the passive cooling
• What's your cable run length? Voltage drop on long cables can trigger protection that looks thermal
• Any chance it's a firmware thing? There was a dodgy batch of Orion firmware last year that caused phantom throttling

My static caravan setup runs a 30A Orion into Fogstar Drift lithium and it's been flawless since I sorted the airflow — but that took an embarrassing amount of forum lurking to figure out, so you're already ahead of where I was.

What's your install look like — enclosed locker or open mounting?

@MasterWanderer has nailed the most likely culprit, but worth also checking whether you've got the correct input voltage threshold set — if your alternator is a smart/variable-voltage type (common on anything post-2015 Euro 6), the Orion can interpret the lower charge voltage as a "engine off" signal and throttle accordingly, nothing to do with heat at all.

The Victron Connect app will show you the charge state history, so you can rule out one before chasing the other — temperature fault vs input voltage dropout look completely different in the logs.

My own Orion lives on a small aluminium bracket with a 40mm fan I nicked from an old PC; runs stone cold even on a six-hour motorway slog to Scotland.