Charlie and Ardhuru

Taking on board what you are both saying.... My problem is space as well as power consumption. At the moment my circuits are draining 0.860mA sleeping and 20mA (5v) when awake.... No ADC's yet.

2AA's is about as much space as I can afford...Given the really good LDO (0.2mV Typical) of the regulators mentioned I could in theory use 1 18650 Lithium-Ion Battery @3.7v 2000mA and still have 3.3mV Available as a regulated output if I was to drop to a LF Pic?

Thank you for reading

Andy