On Sunday, August 16, 2015 at 7:19:25 PM UTC-7, Brian wrote:
One point I haven't seem mentioned as a common issue with any device is miminum voltage, many devices require 12 volts or more which can be difficult to maintain with batteries for more than a few hours especially at high altutudes. This is why Becker, Dittel and Trig equipment is often so popular as they are usually specéd to operate down to 10 volts.

Brian

THis is a non-issue today. Using LiFePO4 batteries solves virtually all power problems. I flew last week with a 15Ah LiFePO4 Powerizer battery. I flew for 5 days, total of 20.7 hours. An Oudie, Flarm brick, LX S80 vario, radio and Trig transponder. All were on starting at least 30 minutes before launch and at the end of the last day I was still seeing 12.4 volts. All systems working perfectly.