> I'm thinking of using a single 1.5 volt AA battery to power my board.

One thing to remember: TANSTAAFL (there ain't no such thing as a free 
lunch).

Let's assume you have an AA battery rated at 2000maH.

First, This specification does not, by the way, necessarily mean that you 
can draw 1000ma for two hours, or 2000ma for one hour, or 100ma for twenty 
hours. It is measured at a given discharge rate [see the datasheet :-)] and 
at higher rates the available power will be less. This is (at least partly) 
due to the energy dissapated in the battery's internal resistance, which 
goes up as the current goes up.

Second, with a 1.5V source you are going to need some sort of step-up 
converter. Conservation of energy says that the current into the converter 
will always be (at least) proportionally greater than the current out. For 
example, given a 100% efficicient converter from 1.5V to 5V (which of course 
doesn't exist), drawing 500ma out would require 500ma*5V/1.5V = 1666ma input 
current (TANSTAAFL!).

-- Bob Ammerman
RAm Systems

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