Victron Orion 30A keeps cutting out when engine revs drop at idle

Had the exact same issue last winter with my Orion-Tr Smart 30A. The culprit turned out to be the input voltage threshold — when the alternator drops to idle, voltage can dip below the default 13.2V start threshold momentarily, causing the Orion to disconnect and then struggle to restart cleanly.

A few things worth checking:

• Input voltage settings — In the VictronConnect app, try dropping the "start voltage" to around 12.8V and the "shutdown voltage" to 12.6V. Gives it more headroom at idle.
• Engine-running detection mode — Are you using voltage-based detection or do you have a wire on the ignition feed? Voltage-based is twitchy on older alternators that don't regulate well at idle.
• Absorption/bulk state interaction — If your leisure bank is already fairly full, the Orion throttles back and becomes more sensitive to input fluctuations. Check what state of charge you're starting journeys with.

On mine (feeding a 200Ah Fogstar Drift LiFePO4 in the van), I also added a small delay using the "delayed engine shutdown" setting — this stops it cutting during brief throttle dips in traffic.

What vehicle are you running this in? Some older alternators are genuinely quite noisy voltage-wise and the Orion doesn't always play nicely without a bit of tuning. Worth logging the input voltage over a journey using VictronConnect's built-in data recording — you'll see exactly where it's tripping.

Would be interested to know if others have found specific threshold values that work well for diesel engines — mine feels like it still needs tweaking on longer motorway runs.

@IslandVanLifer worth checking whether you've got the engine detection set to voltage or alternator mode in VictronConnect — if it's on voltage, any idle dip will trigger the disconnect cycle repeatedly.

On my static setup I don't deal with alternators, but I've seen this discussed at length on the Victron community forums. The consensus seems to be lowering the "input voltage lockout" threshold and increasing the restart delay so it doesn't keep cycling.

Also worth ruling out whether it's actually a dodgy connection on the input side causing a transient voltage drop rather than genuine alternator behaviour. Crimp quality and cable gauge matter more than people realise at 30A draw.

@DucatoProject once I switched mine to alternator mode with a proper D+ wire it stopped playing silly beggars entirely — garden office build taught me that stable charge beats fast charge every time.

@NorfolkVanLifer is spot on about D+ mode, but worth adding — if you can't easily run a D+ wire, dropping the input voltage threshold down to around 12.8V in the Victron Connect app often sorts it. Just make sure your input lockout is set a bit lower too, otherwise it'll keep cycling.

Also check your input cable gauge. Undersized wire causes voltage drop under load which triggers the cutout even when the alternator's fine. I had this exact headache on my setup — turned out to be a dodgy crimp on the positive feed, not the settings at all.

If you're on a modern vehicle with a smart alternator, that's a whole different rabbit hole — you'd want an Orion-Tr Smart Non-Isolated and possibly a VSR bypass.

Been through this exact saga with my tiny house setup — though mine was a stationary alternator feed rather than a van, the behaviour was identical.

What nobody's mentioned yet is the absorption-to-float transition timing. When the Orion briefly cuts out and reconnects at idle, it restarts the charge cycle from scratch. Over weeks, this can mask itself as a "cutting out" problem when it's actually a repeated restart loop.

Worth checking your VictronConnect history graph — if you see a sawtooth pattern on the input voltage log, that's your smoking gun.

@MarineGaz makes a solid point about dropping the input threshold, but I'd combine that with setting a restart offset of at least 1.4V above your new threshold. Stops it cycling on and off the moment voltage wobbles around the trigger point.