Victron Orion 30A keeping dropping out on long drives - wiring issue?

Mine did exactly this for three months before I finally admitted the crimp on the input negative was the culprit — classic "works fine cold, throws a tantrum warm" scenario that'll have you chasing ghosts forever.

Few things worth checking before you pull your hair out:

• Input voltage drop under load — measure at the Orion terminals, not at the battery. If you're seeing more than 0.5V drop you've got resistance somewhere in the run
• Cable sizing — the 30A unit wants proper 6mm² minimum, and I'd argue 10mm² if your run is over 2 metres on a narrowboat with all the bilge-damp nonsense
• Engine bay temperature — these units will thermal-throttle and drop out if they're cooking near the alternator. Victron's own documentation is suspiciously vague about this
• Isolation — is your chassis ground shared with anything sketchy? On a boat that's basically asking for trouble

What's your actual cable run length and what gauge are you using? Also, are you on the latest firmware? There was a known dropout issue on earlier Orion-Tr Smart builds that Victron quietly patched.

The VictronConnect app should show you historic input voltage — worth digging through that before assuming the unit itself is at fault, because nine times out of ten it's the wiring rather than the box.

Anyone else had temperature-related dropouts specifically? Curious whether this is more widespread than Victron let on.

@48VQueen nailed the thermal crimp issue, so I won't rehash that.

One thing worth adding — the Orion-Tr 30A has a input undervoltage lockout that kicks in around 11.5V. On long motorway runs your alternator voltage can actually drop slightly under heavy load (think rear screen heater, headlights, climate control all competing). Stick a cheap voltmeter on the input terminals during a drive and log what's actually arriving at pin 1.

Also check your B2B's cable routing isn't running parallel to any ignition wiring — induced noise on the remote L-line can cause spurious shutdowns.

My setup uses 10mm² throughout with rated ring terminals from RS Components, not the cheap bag-of-50 crimps from eBay. The difference in contact resistance under load is measurable.

VictronConnect app will show you the fault history — check whether it's logging undervoltage or overtemperature events.

If your crimp's fine and @RetiredSquaddie's input checks out, don't overlook the engine bay ground loop — my Orion was dropping out every time the alternator got busy, turned out the chassis ground return was doing a tour of the entire van before getting home.

Dedicated negative direct to battery sorted mine instantly — Fogstar won't thank me for saying it, but a solid ground is worth more than a shiny new unit.

Had exactly this on my motorhome — after ruling out everything @48VQueen and @RetiredSquaddie mentioned, check your alternator output voltage under load with a proper multimeter at the Orion terminals, not just at the battery.

Some Euro 6 alternators do clever variable-voltage charging and will actually drop below the Orion's 12.8V input threshold during certain load cycles — the Orion thinks it's protecting itself and shuts off. Completely normal behaviour from both devices, completely maddening to diagnose.

Quick fix: bump the "Input voltage lockout" setting in VictronConnect down a touch (carefully, don't go daft), or wire a small capacitor/buffer across the input.

Fogstar and Victron forums both have threads on Euro 6 alternator compatibility — worth a read before you rewire everything for the third time at a service station car park in the rain. 🌧️

Great thread, everyone's covered the obvious suspects well.

One thing nobody's mentioned yet — check your chassis ground path between the engine bay and the habitation area. If you've got a long cable run to the Orion and the chassis bond at the leisure battery end is dodgy, you'll see exactly this symptom: fine when stationary or on short runs, drops out once everything's warmed up and resistance creeps up.

Worth grabbing a multimeter and measuring voltage drop across that ground path with the engine running. Anything above about 0.2V and you've found your problem. Adding a dedicated ground return cable directly back to the starter battery negative sorted mine completely.

Also, @MarineGeoff — curious what your alternator issue turned out to be? I suspect you might be onto something similar with voltage drop under load.

Good shout from everyone here. One thing I'd add — check the input voltage threshold in the Victron Connect app. The Orion-TR Smart has a configurable "input lockout voltage" that defaults around 11.5V but will cut in/out repeatedly if your alternator output is marginal or there's voltage drop across a long cable run.

On my boat I had identical symptoms. Turned out my cable run was borderline for the 30A draw — bumped from 6mm² to 10mm² and the dropouts stopped completely.

Quick test: chuck a multimeter on the Orion's input terminals while driving and log the voltage. If you're seeing anything below 13V under load, it's either resistance in the wiring or the alternator struggling. VictronConnect's built-in history tab will also show you exactly when and why it's cutting out.