LiIon 3.6V

[neilh10]

FeatureRequest It would be nice if the Mayfly could be specified to run from a 3.6V LiIon Li-SOCL₂

eg D Cell 3.6V Lithium Thionyl Chloride Battery single use ER34615 19AHr, or ER18505 4100mAh
The advantage is a single cell battery, that is specified for an outdoor temperature range.
It is relatively high impedance, so is likely only to support a standalone Mayfly with no or low current Xbee.

Seems like this should be possible.
The AREF has an external capacitor, AREF can be routed internally " Voltage Reference Selections for ADC" and use either the AVCC, or 2.56V or 1.1V
The processor mega1284 supports a voltage range from 1.8-5.5V, so if the LDO could be bypassed it would be able to use a wide dynamic range including that of the Li-SOCl2, standard LiIon rechargeable.
(updated 2021Oct21)