Victron Orion 30A cutting out when engine gets warm — anyone else had this?

Had almost exactly this with mine last summer — took me an embarrassing amount of time to track down.

Turned out the Orion was mounted too close to the engine bay bulkhead in my shepherd's hut van conversion, and once everything warmed up, the unit itself was hitting thermal protection. The Victron app showed the temperature fault history clear as day once I knew where to look.

A few things worth checking:

• Ambient temperature around the unit — these need proper airflow, not just a "it'll be fine" cable run through a hot void
• Voltage at the input terminals when warm — alternator output can droop on older vehicles once the engine's really up to temperature, and the Orion has input voltage thresholds it won't cross
• Wiring gauge all the way back to the battery — voltage drop under load is sneaky and gets worse as resistance rises with heat

The second point caught me out specifically. My van's alternator was healthy when cold but sagging noticeably once warm. The Orion was doing exactly what it should — protecting itself — but it looked like a fault.

Relocating the unit to a cooler spot inside the hut and adding a proper 40A inline fuse close to the starter battery sorted it completely. Been rock solid since.

What vehicle are you running it on, and where's the Orion physically mounted? That'll probably tell us a lot. Others here will have seen this pattern too — it's more common than Victron's documentation really prepares you for.

Classic thermal shutdown — @SolarNeil's covered the obvious culprit but worth checking a few other things too.

On my narrowboat I had similar with an Orion-Tr Smart 30A. Turned out the input cable was slightly undersized — voltage drop under load was causing the unit to work harder than necessary, generating more heat than it should. Swapped to proper 10mm² throughout and temps dropped noticeably.

Also worth checking:

• Are you running it in bulk mode constantly? If your leisure bank is deeply discharged every day, the Orion's working flat-out the whole journey
• Firmware up to date? Victron pushed a fix a couple of years back that affected thermal management on some units
• VE.Direct connected? Makes diagnosis so much easier — you can log exactly when it cuts and what the temps were doing

What's your cable run length and wire gauge?

Has anyone checked the input voltage under load when this happens? I had a similar intermittent cutout on my motorhome build and initially assumed thermal issues, but turned out my alternator was drooping badly under load — Orion was seeing sub-11V on the input and protecting itself.

Worth logging with a Victron Cerbo or even just a cheap multimeter on the starter battery terminal while the engine's warm and the Orion's running. Cold starts can mask a tired alternator that only shows its hand once everything's up to temperature.

Also — is yours the isolated or non-isolated version? I've seen the non-isolated units behave oddly with certain alternator setups.

Good shout from @MultiPlusGeek on input voltage — this is often overlooked. Worth logging with a Victron SmartShunt or even a cheap voltage logger on the alternator output while driving, not just at idle. Alternators on older diesels can sag badly under combined load (A/C, headlights, Orion pulling 30A).

Also worth checking: are you running the non-isolated or isolated variant? The isolated handles marginal input voltages more gracefully in my experience.

One thing I haven't seen mentioned — check your H-line connection. If the Orion isn't getting a clean engine-running signal, the internal algorithm can misinterpret voltage spikes during warm-up as "engine off" and back off the charge current erratically, which can look exactly like thermal shutdown from the outside.

VictronConnect app with Bluetooth dongle will show you the actual shutdown reason in the history — saves a lot of guesswork.

Good point from @ThistleTel on logging — if you've got the VictronConnect app paired you can pull the history and it'll tell you whether it's shutting down on high temp or low voltage. Saved me a lot of head-scratching on my shepherd's hut setup.

One thing nobody's mentioned: check your cable runs aren't undersized. I found my 6mm² feed was borderline for a 30A unit over a longer run — voltage drop under load was masking itself as an intermittent fault. Upsizing to 10mm² sorted it. The Victron wiring calculator is useful here, or just use the Blue Sea Systems sizing guide.

Also worth double-checking the remote on/off wire isn't picking up interference from near the alternator — seen that cause odd behaviour too.