we are determining a power supply for our R-pi project to provide 5v at 1amp.

Assuming this to be 1 Amp Hour then it will consume 5 Watts over an Hour.

If we use it in a remote location unattended for 1 week it consumes

24 x 7 = 168 hours x 5 watts = 840 watts.

man alive! that's close to 1 kilowatt, can that be right?

assuming it is, if we use a 100 AmpHour GelCell at 12v ( with a step down/regulator ) it provides us with 1200 watts, and some to spare correct?

or do we get more because the the 100 ampHour rating is for a 12v draw?,

does drawing only 5v increase the time use, or alternatively be able to use a lower rated battery?