Wawa:
That increases analogue readout by 5/4.6... = ~9% compared to the laptop supply.
But my readings are about 30% different?
Wawa:
External Aref derived from VCC is as instable as VCC.
If you want a stable readout independent of VCC, then use the internal 1.1volt Aref.
And drop battery voltage with a voltage divider to ~1volt.
I understand that but I havent recorded any instability large enough to warrant this kind of change. Ive read that the internal ref has inaccuracies of its own. Would it make sense to tie the pot to 12v regulated output and GND instead