Orion XS 50A DC-DC charger shows voltage in/out but no amps in/out

Had a similar head-scratcher on my narrowboat last season. Running a Victron Orion XS 50A between the starter and a pair of Fogstar 100Ah lithiums in the bow. Voltage readings looked spot on — around 14.2V in, 14.4V pushing to the service bank — but the current display was sat at a fat zero both ways.

Took me an embarrassingly long time to realise I'd not properly configured the engine-running detection threshold in VictronConnect. The Orion was seeing the voltage but deciding the alternator wasn't actually "running" by its own logic, so it was sitting in standby rather than actually doing anything useful. Classic.

Worth checking:

• Input voltage threshold — default is something like 13.2V, but some older alternators on UK-spec vehicles barely kiss that under load
• Allow-to-charge/allow-to-discharge settings if you've got BMS comms set up
• Whether you've actually got the remote on/off wired correctly

Anyone else found the Orion XS particularly fussy compared to the older Orion-Tr Smart? I had an Orion-Tr on my static caravan setup and it felt more... forgiving somehow. The XS seems to want everything configured precisely or it just sulks.

Also — what's your alternator situation? Some of the older, non-smart alternators in pre-2020 vans and boats can behave oddly with DC-DC chargers that are expecting a more predictable charge profile. Would be curious what vehicle/engine you're running this off.

@ShedGenius the voltage looking right but zero amps is almost always the input voltage not actually reaching the minimum threshold to trigger current flow — even if it reads fine on the display. Victron's Orion XS won't push amps until input sits reliably above roughly 13.2V under load conditions, not just at rest.

Check your cable gauge and length between alternator/starter battery and the Orion input terminals. I had this exact scenario on my static caravan setup — voltage displayed 13.8V but under any draw it was sagging below threshold due to undersized cable run. Swapped to 35mm² and it sorted immediately.

Also worth checking: is the remote on/off wire actually energised? Sounds daft but I've seen that catch people out more than once.

@FormerMechanic14 has the right scent but let me add the twist in the tale — on my boxer-van-turned-narrowboat-support-vehicle, I had exactly this gremlin and the culprit was the remote on/off wire floating unconnected. Orion XS won't push a single amp without that line properly pulled high (or bridged, depending on your wiring scheme).

Second suspect: check your input cable voltage drop under load. Victron's minimum threshold is around 11.5V — your multimeter at the battery terminal reads fine, but at the Orion's input connector? Different story entirely once you load it up.

Worth grabbing a VictronConnect Bluetooth read whilst the engine's running — the live data screen will tell you exactly why it's throttling. Nine times out of ten it logs a protection event that gives the game away immediately.

@ShedGenius worth checking if your Orion XS is in storage mode via VictronConnect — mine sat there looking perfectly healthy for a week before I realised it had basically gone into a sulk because the input hadn't hit the threshold voltage long enough to convince it the engine was actually running rather than just being bump-started by a swan.

Good shout from @CornishNomad on storage mode — caught me out too on my van build.

One angle nobody's mentioned yet: wire gauge over distance. On a narrowboat the run from starter battery to bow can be substantial. Under load, even "correct" voltage at the Orion input can collapse below the engine-detection threshold the moment it tries to pull amps. The unit sees low voltage, assumes engine isn't running, and politely refuses to charge.

Grab a multimeter and measure input voltage while the Orion is attempting to start — not at idle. If you're seeing a meaningful drop versus your alternator output, you've found your culprit.

I ran 25mm² cable on my motorhome build specifically because the Orion XS is unforgiving about this. Worth checking your fuse holders too — a corroded blade fuse can mimic the exact same symptom.