question

The Absorption is the Bulk setting.

Ie you set the absorption to 14.1 (as a example) this means that the unit is in bulk until it reachs the 14.1 volts thats set then it drops to absorption and holds 14.1 until the Absorption time limit is reached then it goes to float voltage that you have set

In Victron parlance (pretty normal), 'Bulk' is just a phase to be conquered in pursuit of the Absorb target. So the target is already specified, but some algorithms may deliberately restrict progress through Bulk to protect your batts.

Temp compensation may be boosting your V targets too if it's cold there.

That 'acid smell' would ring alarm bells for me. And 14.8V is quite high for Pb's, and I wouldn't go near that myself as a base setting. Some batt makers may supply a suggested range for the 'masses', then might not provide a temp comp factor. Picking the high-end figure will rarely increase charge performance much, maybe just boil water from flooded Pb's, and could kill sealed batts. My Victron kit defaults 14.4V Abs and 13.8V +/- tc, perfect for me anyway.

Your 'one time 17.3V', if just a registered spike, could have been caused by the dropping of a load. In that case nothing to worry about. If you see it remain there then there's a serious issue - something to be fixed.

Edit/: My slow keyboard, sorry Paul.

Thanks for the replies. As to the bulk, clearly the definition has been to throw everything at it until the bulk voltage limit is reached. My two aging Sears label Odyssey 100Ah TPPLs came with recommendation of 14.8V bulk limit and 14.7V absorption. So, no big deal if Victron chooses to use the same value for both, I set the absorption limit to 14.75V, My Smart Battery Sense has been reliably transmitting 20 to 25 deg battery temperature readings here in sunny Florida since installed a month ago. I don't have much in the way of loads, so by morning I see a deficit of around 35 - 42Ah on the BMV702. By early afternoon, the batteries are around 24 C / 75 F as per VictronConnect on my phone and the BMV702 is reset to full charge, Tail charging current is around 1A, but probably because of fast MPPT action it oscillates wildly. My little Frigoboat comes on and off with 3 to 4A load on 25min cycle. With the laptop, occasional water pressure pump and some lights average additional load is ~2.5A. Yet when the fridge is off, the voltage climbs to 15.1V. I haven't figured out for how long, but clearly long enough on occasion to make one or both the batteries vent.

Next I will try to lower the absorption limit to 14.6V and see what happens.

OK, lowering the absorption setting to 14.6V now reliably keeps the bulk and absorption below 14.85V. I seems there should not be a 0.25V discreppancy, but I can live with it. I don't have a calibrated multi-meter, but the Smart Battery Sense shows only 0.05V more than the BMV702, which is probably right because of the involved voltage drops. Fluke has been on my wish list for decades now.

For anyone following my ramblings, most lead/acid batteries have lower recommended voltage settings than the TPPLs (Thin Plate Pure Lead) variety.