Anyone else running a Victron Orion-Tr Smart in absorption mode from a vehicle alternator — what settings are you actually using?

Been down a bit of a rabbit hole this week. Fitted an Orion-Tr Smart 12/12-30 between my van's starter battery and a 200Ah Fogstar Drift LiFePO4 in the back. Set it up in standalone mode initially, let it run on the default 14.2V absorption with a 2-hour timer, and it seemed fine — but I kept seeing the Fogstar's BMS kick out around the 95% mark before absorption had even finished.

Dropped the absorption voltage to 14.0V and cut the timer down to 20 minutes, and the BMS drama stopped. Battery's still getting to around 98% on a decent run, so I'm not losing much. But I'm genuinely not sure if I'm leaving capacity on the table or if the default Victron settings are just a bit aggressive for lithium out of the box.

The van does a mix of short commutes and longer weekend trips, so the service battery doesn't always start from a resting state. Wondering if anyone's dialled in something smarter — particularly around the engine detection threshold and whether you're bothering with the absorption phase at all for LiFePO4.

What's your real-world experience?

Good question. Running the same unit on the narrowboat between the engine starter and a 200Ah LiFePO4 bank.

What I've found works reliably:

• Absorption voltage: 14.2V
• Absorption time: 20 minutes (fixed, not adaptive)
• Float: 13.5V
• Tail current: disabled — Victron's adaptive absorption doesn't play nicely with alternator input fluctuations in my experience

The key thing people miss is that your absorption time needs to account for the fact that alternator output isn't clean or consistent like a mains charger. Short, fixed absorption is safer than letting it run adaptive.

Also worth checking your alternator's actual output voltage under load before setting anything. Mine sits around 14.1–14.4V depending on engine speed, so there's not much headroom to play with.

What firmware version are you on? There were some quirks in earlier builds with standalone mode.

Great thread. One thing worth flagging that I haven't seen mentioned yet — keep a close eye on your alternator temperature if you're running sustained absorption on longer motorway runs. The Orion-Tr Smart will happily pull its full 30A continuously, and older or smaller alternators can struggle with that.

I've got mine set with the engine-running detection threshold at around 13.2V to avoid any false triggers, and I'd strongly recommend enabling the variable absorption feature if your battery is rarely fully depleted — it genuinely reduces stress on the alternator by shortening absorption time when the bank doesn't actually need it.

@SolarJason what alternator are you running? Some of the newer Ford Transit units have smart charge management that can cause headaches with DC-DC chargers — worth checking whether yours is outputting a proper charging voltage or dropping to around 12.8V once warm.

Really useful thread this. I've got the same unit in my off-grid camper build and spent ages dialling in the settings last winter.

One thing I'd add — the input current limit is your friend here. I've got mine capped at 25A rather than the full 30A draw, which keeps things gentler on an older alternator during long idle periods. Makes a difference when you're running the engine just to top up the battery.

Also worth enabling the engine detection via D+ signal if your van has it wired up — stops the Orion trying to pull power during cranking. Victron's own app makes this dead easy to configure.

@JakeLee raises a fair point about alternator temps — especially relevant on older Ford Transit-based vans where the alternator is already working hard just running the standard electrics.