So far I've selected two way to power my WSN/JN setup - AA board or 3xAA Battery holder.
To make things even "easier", it is possible to use completely different battery types - Alkaline and rechargeable (I prefer Eneloop).
Lets collect some opinions....
With more than one battery, a resistor voltage divider is the easiest solution, but I'm a bit concerned about the extra power drain (10kOhm == 330uA), because we should avoid "bad" design.
Another point is how to connect wires (or avoid them). There is no provision for such a direct battery power measurements, AFAIK, on either AA board or JN6, but there is a lot of space and there is one unused pin on FTDI header.
So, expected requirements:
"Prior art" - TODO: