Orion xs settings AGM

Been down this exact rabbit hole with AGM settings on the Orion XS, so thought I'd chip in.

I've got one running in my garden office build — 12V system, 200Ah AGM bank, fed from a vehicle alternator via the Orion XS. The Victron defaults out of the box are fairly conservative, which is sensible for longevity, but if your AGM manufacturer is specifying 14.7V absorption you're right to override that manually.

A few things worth checking though:

• Temperature compensation — AGMs are quite sensitive here. If your battery is in the engine bay or boot and seeing temperature swings, that absorption voltage should ideally be dropping around 3–4mV per cell per degree above 25°C. The Orion XS doesn't have a battery temp sensor input like the SmartShunt does, so factor that in if you're running through summer.
• Absorption duration — what have you set? The default adaptive mode can sometimes overcharge AGMs if the battery was deeply discharged to begin with. I run a fixed 2-hour absorption on mine.
• Float at 13.8V looks spot on — that's pretty standard for AGM.

The bigger question with a standard 140A alternator is whether you're seeing input voltage drop causing the Orion XS to throttle back. Worth checking the VictronConnect graphs — you can see input vs output voltage logged over a journey which is genuinely useful for diagnosing alternator strain.

Anyone else running AGM with the XS on a higher-output alternator had better results? Wondering whether a 180A unit would make much practical difference given the XS is capped at 30A output anyway.

@KeithMurray what AGM are you running? Makes a difference — some of the sealed units like Victron AGMs want slightly lower absorption than generic ones.

On mine in the motorhome I've got the Orion XS set to 14.4V absorption, 13.8V float, with absorption time around 2hrs. Works well for the Fogstar AGMs I had previously.

Main thing people miss is the storage voltage — worth setting that properly if the vehicle sits unused for weeks. Drops it back to ~13.2V which is kinder long term.

What's your alternator? Smart or dumb? Changes the approach a bit on the XS settings.

@RobJones85 makes a fair point. I'm running Fogstar AGMs and found 14.4V absorption works well — didn't want to push to 14.7V even though some specs say you can. Float at 13.5V seems spot on for longevity.

One thing worth checking — the Orion XS adaptive mode can be a bit aggressive if your alternator voltage is already sitting high. I manually set mine rather than letting it guess.

What's your alternator putting out at the B+ input? If it's already 14.2-14.4V you might not need much absorption time at all.

@KeithMurray worth checking whether your AGM has a gel-style profile option in the Orion XS — some manufacturers spec their sealed AGMs closer to 14.1–14.2V absorption rather than the full 14.4V. I made that mistake early on and noticed the bank running warm after extended absorption periods.

Also worth setting a proper float — I've got mine at 13.5V which keeps things topped without stressing the plates on long static periods in the office.

One thing nobody's mentioned: if you're on an older alternator without smart charging, the Orion XS input voltage sensing can sometimes misread state of charge. Check your DC cable sizing too — voltage drop on the input side throws the whole thing off.

@LazyBodger raises something I hadn't considered initially — worth cross-referencing the battery manufacturer's datasheet rather than just selecting "AGM" and assuming it's correct. The Orion XS gives you custom voltage entry which is genuinely useful here.

On my setup specifically, I'm running Platinum AGMs at 14.4V absorption, 13.8V float, with absorption time locked at around 2 hours rather than letting it run adaptive. AGMs genuinely don't love prolonged high-voltage absorption — they gas and dry out internally over time.

Also worth noting: if your alternator feed cable is long, you'll see a voltage drop that makes the XS think it's hitting absorption when the battery isn't actually there yet. Enable the tail current setting if your firmware supports it — far more accurate termination than pure time-based.