Orion 12-12 30A dragging starter battery DOWN!

Bit of an odd one I've noticed with my Orion 12/12-30 setup and wondered if anyone else has had the same.

Running it in my motorhome — solar into a Victron MPPT feeding the 200Ah Fogstar lithium house bank, then the Orion pulling from that to top up the starter battery. Works a treat most of the time.

Problem is, on overcast days when the MPPT is barely keeping up, the Orion seems to drag the house bank down faster than the panels can recover. The 13.1V threshold kicks it on, but the solar input at that point is maybe 8-10A and the Orion wants 30A. Net result — house bank slowly bleeds down rather than charging the starter.

A few things I've tried or considered:

• Raising the threshold voltage on the Orion — makes it less trigger-happy
• Dropping it to the 15A profile via VictronConnect when conditions are marginal
• Setting a lower input voltage cutoff so it backs off before the house bank suffers

Currently leaning toward the voltage cutoff option as the most hands-off fix.

Anyone else juggled this? Feels like it should be straightforward but the interaction between MPPT output and DC-DC draw is trickier than I expected. Particularly interested if anyone's using the MPPT's load output or a BMS signal to inhibit the Orion when solar's poor.

Hey @DownsCruiser — looks like your post got cut off there, but I think I can guess where you're going! Classic symptom is the Orion backfeeding through the unit when the starter battery voltage drops below the leisure bank, especially if you've not got the engine-detect/ignition input wired in properly.

The Orion non-isolated needs that ignition wire connected, otherwise it'll potentially run in reverse or activate at the wrong times. Worth double-checking your H terminal wiring.

If you're running the isolated version and it's still dragging the starter down, check whether your input threshold voltage is set sensibly in VictronConnect — sometimes the defaults catch people out.

What version have you got, isolated or non-isolated? And are you seeing this happen with the engine running or just on hook-up? That'll help narrow it down considerably.

@DownsCruiser post got cut off so I'm guessing slightly here, but the most likely culprit is the Orion non-isolated version back-feeding through the internal body diode when the starter battery drops below the house bank voltage.

Seen it myself on my static caravan setup — Orion was dragging the feed battery down overnight because the input/output voltage differential reversed.

Two fixes:

1. Upgrade to the isolated Orion-Tr Smart 12/12-30 — proper galvanic isolation, no back-feed path
2. Fit a standalone relay or VSR on the input side to physically disconnect when the alternator isn't running

The isolated version is the clean solution. Non-isolated Orions are fine for certain applications but lithium house banks complicate things because they hold voltage so flat and firm — the starter battery loses the fight almost every time.

What's your current model number off the unit itself?

Something similar happened to me last winter when I was parked up in the Forest of Dean for a fortnight — woke up on day three to a sluggish starter.

Worth checking one thing nobody's mentioned yet: the Orion's enable wire connection. If it's wired directly to ignition rather than through the proper VSR logic or a Victron BatteryProtect, it can sometimes activate at the wrong moment and reverse the expected flow direction when your alternator isn't running.

Also double-check your VE.Connect app — the Orion logs charge history and you can see exactly when it was drawing versus supplying. That little graph told me immediately what mine was doing overnight that I'd never have spotted otherwise.

What voltage is your starter battery sitting at when you notice the drag? That figure would really help narrow it down.

@DownsCruiser your post got clipped but I'm fairly sure I know what you're describing — the Orion pulling the starter battery down even when the engine's off and solar is doing the heavy lifting?

Worth checking your storage enable/disable wiring if you're using the non-isolated version. There's a tiny but real quiescent draw that can sneak through overnight. More importantly, have you set the input voltage threshold correctly in VictronConnect? If it's set too low, the Orion can activate off residual voltage rather than genuine charging voltage from the alternator.

Also — and this catches people out — make sure you haven't got the input and output terminals swapped. Sounds daft but I've seen it happen after a reinstall. The unit will still "work" but behaves very strangely.

What firmware version are you running? There were some fixes around this in earlier releases.