You should let it run idle and see how long until the battery is depleted. I underestimated the losses due to efficiency with my Libretto project (boost convert

You should let it run idle and see how long until the battery is depleted. I underestimated the losses due to efficiency with my Libretto project (boost converters run at different efficiencies depending on the power draw). I was able to get about 4 hours on a 6600mAh battery pack powering a Pi and a 7" touchscreen with wifi and bluetooth enabled (the project draws about 8W when the screen is turned on, about 5W with it turned off).