Phil Spiegel said:
Would Paralleled pairs of AA"s offer a useful solution – with more current capability – but still requiring UP conversion?
Connecting batteries in parallel is IMHO a big No-No, as the lowest batt draws power from its siblings. Placing an empty and a full batt side-by-side might lead to damaged batteries and dripping acid, or even fires.
OK, one could (to be precise: SHOULD) add diodes, but that would waste too much power.
Another idea (as I thought about connecting the RPi via serial) was to use a CAT5 for the serial line, and just provide a 48V source via the unused lines, and then just step down from 48V to 5V, or use the daughter board to connect to the TP ethernet pins 4,5,7,8 to draw from PoE, and skip the UART altogether.