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

Mine did exactly the same until I realised the absorption timer was set to something daft like 20 minutes — Victron's default assumes your battery tells it when it's done, but if you've not got comms wired up it's just guessing like a blindfolded dart player.

A few things worth checking:

• Are you running VE.Direct or just dumb mode? Without the cable you're flying blind and so is the Orion
• Battery temperature — my Fogstar Drift 100Ah was throwing the unit into float early on warm days because the voltage looked right but wasn't
• Absorption voltage set correctly for your chemistry? LiFePO4 and AGM are very different beasts and someone always forgets to change the defaults

I've got mine wired into a garden office setup so it gets proper long absorption sessions on leisure runs, but even then I had to manually bump the absorption time to 4 hours before it stopped being a drama queen about it.

The Victron Connect app is your friend here — plug in, look at the charge history, and see exactly where it's bailing out. If it's consistently hitting float at 80-something percent state of charge, it's not seeing the tail current drop it's expecting.

Has anyone else found the 30A specifically worse than the 18A for this? Mine behaved better once I got comms sorted but I wonder if it's a unit-specific quirk or just motorway voltage being inconsistent.

@GrumpySpanner — worth also checking your tail current threshold in VictronConnect, because if the Orion thinks the battery's "full" based on a suspiciously low current draw (common with longer cable runs adding resistance and skewing the readings), it'll happily toddle off into float while your lithium is still sitting at 60% SOC wondering what happened to its lunch.

Great points from @GrumpySpanner and @FETFan. One thing neither of you have mentioned yet — check your wiring voltage drop between the alternator/starter battery and the Orion's sense inputs. If the unit is seeing a falsely elevated voltage due to poor sense wiring, it'll think absorption is further along than it actually is and cut to float prematurely. Happened to mine on a van build last year. Stick a multimeter on the input terminals whilst the engine's running and compare it against what VictronConnect is reporting — if there's a discrepancy of more than a few tenths of a volt, your sense wiring's the culprit. Worth ruling out before diving too deep into the timer settings.

@GrumpySpanner and @FETFan have covered the software side nicely. Just to add another angle — have you checked your alternator output voltage under load? Some modern Euro 6 engines use smart alternators that deliberately drop output voltage when they decide the starter battery is sufficiently charged. The Orion sees that reduced input voltage and can misinterpret the situation, cutting absorption short before your leisure bank is properly topped up.

Worth plugging in VictronConnect while moving (passenger does it, not you!) and watching the input voltage graph in real time. If you're seeing it fluctuate or drop below around 13.2V on a run, that's likely your culprit rather than any timer setting. Some folk solve this with a VSR bypass or by fitting a DC-DC with alternator detection mode enabled. What vehicle is it?

@GrumpySpanner @ValleyCruiser @FETFan @PanelMike — brilliant troubleshooting from everyone, but nobody's asked the classic question yet:

have you actually turned it off and on again? 🤣

Jokes aside, on my narrowboat setup I found the Orion was also throwing a wo