Troubles with Victron Orion-Tr Smart 12/24-15A (S/N: HQ2501*****

Interesting one this — I've been running a similar B2B setup in my van for about 18 months and hit a comparable wall around the 8-month mark.

My configuration is a single 12V/200Ah Fogstar Drift LiFePO4 feeding a Victron Orion-Tr Smart 12/24-15A into a 24V service bank. The unit started throwing protection faults intermittently, and I initially blamed the batteries.

Turned out the culprit was input voltage drop under load — the Orion is surprisingly sensitive to this. When my alternator wasn't fully up to speed (cold starts, short urban runs), the input would sag just enough to trigger the low-voltage lockout. The unit would then refuse to restart without a manual reset via the VictronConnect app.

A few things worth checking in your situation:

• Firmware — make sure you're on the latest version. Victron pushed an update that improved the restart behaviour noticeably
• Engine remote wire — are you using the H/L terminals for alternator sense? If not, the unit can't distinguish between "engine running" and "engine off but battery full"
• Cable sizing — the HQ2501 batch seemed particularly fussy about voltage drop on the input side. I went from 10mm² to 16mm² cable and it made a real difference

Worth pulling the diagnostic data from VictronConnect and posting the screenshots here — the fault log is quite detailed and usually points directly at the issue.

Has anyone else with an HQ25 serial range noticed this? Wondering if there's a batch-specific quirk worth flagging to Victron UK support.

@QJ_Builds worth noting that the Orion-Tr Smart in isolated mode behaves quite differently to non-isolated when it comes to BMS communication — or rather, the complete lack of it. On my narrowboat I run a 12V→24V isolated unit feeding my service bank, and what caught me out was the input voltage threshold interaction with a Fogstar Drift's LiFe chemistry specifically.

LiFe sits at roughly 13.2V resting, and if your alternator isn't pushing above ~13.4V consistently (common with older vehicles under load), the Orion's input lockout can cycle repeatedly. Check your Engine Shutdown Detection setting in VictronConnect — if it's set too sensitively it'll interpret low-charge alternator output as ignition-off and disconnect mid-charge.

What's your alternator output voltage under load?

@QJ_Builds 8 months is almost impressively consistent for a failure point — like the unit had a calendar and a grudge.

One thing worth checking that nobody's mentioned: the input voltage threshold settings in the VictronConnect app. The Orion-Tr Smart can get a bit precious about alternator voltage and decide it simply won't bother charging

@QJ_Builds that 8-month window is interesting — I wonder if it correlates with a full seasonal cycle and the unit experiencing its first proper sustained cold weather operation? I've seen thermal cycling cause issues with solder joints on the Victron boards, particularly where there's any vibration element involved (which in a van is basically constant).

Worth checking whether the fault appeared after a particularly cold spell or a long motorway run. Also, what's your alternator type — if it's a smart/EFB-compatible alternator with variable voltage output, the Orion can sometimes struggle to maintain a stable input reading and get confused about charge states. Victron's VictronConnect app should show historical data logs if you haven't already pulled those — could give you a clue about exactly when it started misbehaving.

@DaleSeeker seasonal thermal stress is plausible but I'd look at the BMS interaction before blaming temperature cycles.

On my boat setup I had a Victron Orion-Tr Smart doing something similar — turned out the Fogstar's BMS was occasionally throwing a protection event that the Orion wasn't handling gracefully. Not a failure as such, more a slow degradation in how the two were communicating.

Worth checking:

• What does VictronConnect actually show in the history tab around the failure point?
• Is the Orion in engine-detection mode, and if so, what threshold is it set to?

The 8-month consistency does make me suspicious it's a configuration issue rather than hardware failure. Units don't usually develop faults on a schedule unless something external is triggering them repeatedly. Pull the data logs before assuming the Orion itself is the problem.