I kept my VA4s at minimal setup (BT on, no Pulse Ox, no WiFi, Infocal watch face, Battery gadget) for a while and the battery is ~6 days.
However, whenever I added a custom datafield for running, the battery start to drain significantly faster. i tried Dozen run/single field/Grun, all have the same issue. I suspect that it is related to GPS settings, but want to see if anyone else experience the same.