Hello I’m trying to power this three boards for an altitude balloon project.
I know that the Cellular Shield with SM5100B (http://www.sparkfun.com/products/9607) needs a 2000 or more mAh to keep it up (I’m considering a 2700 mAh - Lithium Ion Polymer Battery - 3.7v).
The Arduino UNO R3 is also connected with some other sensor that are plugged in the datalogger shield (url below), so I consider to run it with 6 AA Lithium 1.5v 3000 mAh.
I know the datalogger shield (https://www.adafruit.com/products/243) is going to run ok, but how do I connect a separate power source for the cellular shield? And where do I connect?
I need the datalogger on top of the boards (if possible), so I’m a bit lost here and also new in this stuff, but ITS GREAT STUFF! 
Thank you and sorry for my english,
Daniel P.