Victron Orion 30A keeps going into float too early on long drives

Had the exact same drama with mine last winter — turns out the Orion was reading the van's alternator voltage as "battery full" because my leisure battery (Fogstar 100Ah LiFePO4) was already sat at a decent state of charge before I even turned the key.

The fix that actually worked for me: bump the absorption voltage threshold up slightly in VictronConnect so it doesn't trigger float prematurely. Worth double-checking your battery profile is set to lithium and not AGM too — I'd somehow managed to leave it on AGM like a proper muppet, which will absolutely cause this.

A few things worth ruling out:

• Alternator output voltage — some modern Euro 6 vans run "smart alternators" that drop voltage when they think the starter battery is full, which confuses the Orion enormously
• Cable runs — if your voltage sense is picking up drop across a long cable, it'll misread the actual battery voltage
• Battery BMS — if your BMS is doing anything funky it can send the Orion mixed signals

The smart alternator issue is a whole separate rabbit hole if that's your van, mind you — some folk have had to wire the Orion's remote on/off to a dedicated ignition feed just to keep it behaving.

What van are you running and what leisure battery chemistry? Makes a big difference diagnosing this properly. Plenty of folk on here have cracked it so stick your setup details in and we'll throw ideas at it.

@CotswoldDweller this is a classic absorption threshold trap with LiFePO4 on the Orion-Tr Smart.

Worth checking two things in the VictronConnect app:

1. Absorption voltage — if it's set anywhere near 14.2V, the alternator's natural regulation voltage will trigger it almost immediately on a warm battery
2. Absorption time — drop this to the minimum (1 hour) as a stopgap

What actually solved it on my shepherd's hut build (Orion feeding a Fogstar Drift 200Ah) was enabling "Charger only" mode and setting absorption to 14.4V with a 2-hour window. The Orion then ignores the chassis battery voltage entirely and makes its own charging decisions based on output current taper.

Also worth confirming your alternator isn't naturally sitting at 14.2–14.4V under load — some modern smart alternators will fool the Orion repeatedly regardless of settings.

@CotswoldDweller @BordersExplorer — yeah this tripped me up on my static van setup too. The Orion-Tr Smart's default absorption voltage is tuned for AGM, so with LiFePO4 it'll hit that threshold almost immediately if the battery's already at 90%+ from shore power or solar.

What actually fixed it for me: drop your absorption voltage to around 14.2V and set a proper tail current in VictronConnect rather than relying on the timer. The Orion doesn't have tail current natively like the MPPT does, so you're essentially stuck using the time-based absorption — which is useless on a short run.

Also worth checking whether you've got the isolated or non-isolated variant, because the wiring topology affects how it reads source voltage. Some people accidentally misconfigure it and wonder why float kicks in at Tesco.

Great thread, this caught me out too last year. One thing nobody's mentioned yet — check whether you've got the engine detect threshold set correctly in the VictronConnect app. If your alternator voltage is on the lower side (some modern smart alternators with variable voltage regulation can dip quite a bit), the Orion might not even be recognising a proper charge cycle and is essentially playing catch-up from the moment you set off.

Also worth looking at your tail current setting. On LiFePO4 that should typically be around 1-3% of battery capacity — too high and it'll exit absorption prematurely thinking the battery's satisfied when it isn't.

@CotswoldDweller what's your actual alternator output voltage showing in the app during a run? That'd help narrow things down considerably.

@MarshHermit raises a really good point about the engine detection — that one nearly had me stumped on the boat last spring.

What I'd add from bitter experience: if your Fogstar is coming into the drive already sitting at 95–98% (because you've been on shore power or solar beforehand), the Orion genuinely has almost nothing to do. It'll sniff the absorption voltage, shrug, and call it a job well done.

My fix was building in a small deliberate load before longer drives — running the inverter briefly, that sort of thing — just to give the Orion something meaningful to chew on.

Also worth popping into VictronConnect and lowering your absorption voltage slightly for LiFePO4 specifically. The defaults are tuned more towards AGM thinking than proper lithium chemistry.