Orion 24/12-70 voltage drop

Had a similar headache in my van build — running a Victron Orion-TR Smart 24/12-70 to step down from my 24V Fogstar Drift lithium bank to feed the 12V leisure circuits, and noticed the output was consistently sitting about 0.4V shy of what I'd dialled in on the Victron Connect app.

Turns out my cable run to the load was doing most of the damage — classic voltage drop across undersized wire over a longer-than-ideal distance, compounding whatever the converter itself was already trimming off internally.

Few things worth checking if you're seeing something similar:

• Cable gauge vs. run length (the Victron cable sizing guide is genuinely decent for this)
• Whether your Orion is in standalone or connected mode — behaviour differs
• Remote sensing, if your unit supports it (spoiler: the non-Smart versions don't)
• Actual measured voltage at the load vs. at the converter output terminals — those two numbers will lie to you differently

Mine ended up being a combination of 6mm² cable where I really needed 10mm², plus a dodgy Anderson connector I'd bodged together at 2am in a layby somewhere near Cheltenham (don't ask).

Bumped the output compensation up slightly in VictronConnect and re-did the cabling properly and it's been rock solid since.

Anyone else running a dual-bank setup with a DC-DC converter as the bridge between different voltages? Curious whether others have found the Orion plays nicer with lithium than AGM in terms of charge curve consistency — my old AGM setup was considerably more dramatic about the whole

Hey @CotswoldDweller — worth checking your cable sizing between the Orion and your 12V distribution. The 70A output needs beefy cable, and even a modest run with undersized wire will show consistent voltage drop under load. Also, have you checked the remote on/off wiring? A dodgy remote line can cause the Orion to throttle output unpredictably.

One thing that caught me out on mine — the Orion's input voltage cutoff interacting with a sagging 24V bank under heavy simultaneous loads. Even healthy lithium can dip enough to make the Orion grumble.

What's your actual measured output voltage under load versus no load? That'll tell you whether it's the unit itself or downstream resistance. Worth grabbing a clamp meter on the output too to see if it's actually pushing the full 70A when you'd expect it to.

Great thread this. One thing worth checking that hasn't been mentioned yet — have you configured the output voltage in the VictronConnect app? The Orion-TR Smart defaults to around 13.6V output but you can nudge it up to 14.2V or so if your 12V loads need a bit more headroom. Also worth verifying the unit isn't going into current limiting due to thermal protection — if it's tucked away without decent airflow it'll throttle back automatically. What's your installation like, @CotswoldDweller? Mine runs noticeably cooler since I gave it a proper ventilated enclosure rather than stuffing it in a cupboard.

@CotswoldDweller the output voltage trimming in the VictronConnect app is the obvious one, but also worth double-checking your input voltage threshold settings. If the Orion is seeing the 24V bank dip under load and hitting its low-voltage cutoff, it'll throttle output before shutting down entirely — looks a lot like a voltage drop issue but it's actually self-protection.

What's your BMS set to for low-voltage disconnect? If it's cutting in around the same point the Orion starts complaining, you'll get this cascade effect.

Also — are you running the Orion in standalone or connected mode? Networked mode via VE.Smart sharing can smooth out some of the edge cases if you've got other Victron kit on the 24V side.

Good point from @CurrentAffairs on the app config. One thing nobody's touched on — check your input voltage under load. If your 24V Fogstar bank is sagging (either from a weak cell group or a BMS that's throttling current), the Orion's output regulation will suffer. Mine on the narrowboat did something similar; turned out the BMS was limiting discharge current during cold mornings and the Orion was chasing a moving target.

Worth logging input and output voltage simultaneously in VictronConnect during a decent load cycle. The trend data will tell you immediately whether it's an input issue or something internal to the converter.

Also double-check your remote on/off wiring if you're using it — a marginal connection there can cause odd behaviour that looks like voltage instability but isn't.