Victron Orion not playing nice with my leisure battery bank — any ideas?

Been having a similar headache with my setup on the narrowboat. Running a Victron Orion-Tr Smart 12/12-30 feeding a 200Ah Fogstar Drift lithium and it took me ages to figure out why it kept dropping out intermittently.

Turned out the engine battery voltage was dipping just enough under load to trigger the Orion's low-voltage disconnect before it could properly bulk charge the leisure bank. Worth checking your input voltage thresholds in the VictronConnect app — the defaults aren't always sensible for every alternator setup.

A few things worth looking at:

• Input shutdown voltage — are you running the default 11.5V? Might need tweaking depending on your alternator
• Engine detection — are you using voltage sensing or a physical D+ signal? The voltage sensing can be a bit twitchy
• BMS interaction — if you've got a lithium bank, is your BMS throwing any absorption/float rejection signals back at the Orion?

On my motorhome I had a totally different issue where the Orion and the MPPT were essentially fighting each other because the shared bus voltage was confusing both units. Sorted it with proper Victron networking via VE.Direct.

What battery chemistry are you running on the leisure side? And have you got the Orion set to standalone or networked mode? That changes quite a lot about how it behaves.

Would be good to know your full setup — alternator output, cable runs, fuse ratings — because sometimes it's something embarrassingly simple like voltage drop across an undersized cable giving the Orion a false picture of what's actually happening.

@BerlingoConvert did it drop out randomly or consistently after a certain runtime? I had a similar issue with my emergency backup setup where the Orion kept hitting absorption too early and then just... stopping. Turned out my engine battery voltage was sagging under load and the Orion was interpreting that as "job done" on the input side.

Worth checking a few things:

• What's your input shutdown voltage set to in the VictronConnect app?
• Are you running engine-detection mode or a dedicated ignition wire?
• Any significant cable run between alternator and Orion input?

Voltage drop over longer cable runs can cause all sorts of odd behaviour. If you're on 12V and losing even 0.3V across the cable that can confuse the unit's engine-detection logic quite badly.

What firmware version is the Orion on?

@BerlingoConvert worth checking whether your Orion is configured for lithium or still sitting on the default AGM absorption/float profile — caught me out badly on my shepherd's hut build last spring. The Drift has a fairly tight upper voltage tolerance and if the Orion overshoots even briefly it'll trigger the BMS protection, which looks exactly like a random dropout.

Also check your engine battery sensing wire. On my narrowboat the Orion was occasionally reading a false "engine off" signal due to voltage sag on a long cable run, causing it to shut down mid-charge. Adding a 10A inline fuse closer to the alternator and going up a cable gauge sorted it completely.

The Victron Connect app will show you the charge state history — if it's cutting at absorption rather than float, that's your BMS reacting rather than the Orion itself faulting.

Hey @BerlingoConvert, one thing I haven't seen mentioned yet — have you checked your engine battery voltage threshold settings in the Victron Connect app? On narrowboats especially, if your alternator isn't keeping the starter battery topped up brilliantly (older engines can be guilty of this), the Orion might be cutting out because it thinks the input voltage has dropped too low, rather than anything being wrong on the leisure side.

Worth having a look at the "input voltage lockout" setting and maybe dropping it slightly if your starter battery sits on the lower end. Also, are you running the H and L wires for the ignition sense, or relying on voltage detection mode? The latter can be a bit twitchy in my experience. Let us know what @AshWalker's suggestion throws up first though, as the absorption settings are probably the quicker win to check. 🙂

@AshWalker makes a fair point about the absorption profile, but there's another culprit nobody's mentioned yet — the engine-side voltage detection.

On the Orion-Tr Smart, the default "engine running" threshold is 13.2V. If your alternator is even slightly lazy on tickover, or you've got any voltage drop across a long cable run, the Orion will decide the engine's off and shut down mid-charge. Drove me absolutely crackers with my cabin setup before I found it.

In the VictronConnect app, go into the Orion settings and check your input voltage shutdown threshold. Some people bump the "engine running" detection down to 12.8V, though personally I wouldn't go lower than that or you'll start pulling from your starter battery.

Also — what cable cross-section are you running from the starter battery to the Orion? Undersized cable will absolutely murder your voltage readings at the unit itself.