I must be bored, but my alternator kicks out anything from 13.7 to 14.0 (scraping 14.1 sometimes). I have an S4 Bosch battery (which says that the min voltage shd be 12.4V to avoid damage). It's hard to figure out if the Bosch (Varta) battery contains calcium - multiple searches are completely silent - so I guess that means not, although Battery Megastore says it is - Bosch themselves don't seem to say
I'm obviously not getting to drive it much these days, but battery voltage falls below 12.4V fairly often - that said, I never have problems cranking. If the voltage drops then I chuck it on a smart charger every few weeks, and now I have a solar panel on the parcel shelf (jury's still out on that). Guessing that my set point is about 14.0V currently (which I think was on spec for the year/model) then should I look for a VR with a higher set point ? Does anyone have a positive ID on one?