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.

Using product specs I get you are using are drawing about 1A. 2.2 amps when transmitting. What when showing 12.4 amps what does your voltage drop to while transmitting, if not using a low power radio, you may not be transmitting anything readable, although I suspect if the voltage dropped to0 low the LIFEPO4 circuitry would just be shutting everything down. Could be rather annoying to have everything reset when you push the transmit button.

I believe the 15AH battery is the larger size battery similar in size the a 12Ah Lead Acid. Some gliders it is difficult to mount this size of battery..

You obviously aren't getting 20 hrs of use without charging it, the specs don't support that. So would it last on a 8 or 10 hour flight with temps below 0C (I show they do pretty well at low temps only losing about 10% of capacity at 0C). The specs say it probably would work if we don't transmit to much and if you have room for that large of a battery.

Brian