Scott
1. You will do more than consider a two pack setup if you install a digital volt meter (i4c) take a look at it before and after a run-up and taxi around ----- add enough time to the ground experiment to include a flight ----say a total of 12 mins. Then move all flight controls and watch the voltage readings ----- that will be the last time you'll fly with only one pack!
2. OK if you "are sure" the ECU is that new ----- then do the baseline, and full throttle range checks remember you want to see no less than 225 feet full throttle ---- no trans antenna, aircraft above ground level about 3 feet ---- all directions ----same battery pack you have now ---- for this range check --- use the same setup you've been having the "timed trouble with" ------
3. Make sure you do the failsafe setup for the turbine correctly as Tony mentioned. You said you were charging the ECU batt each time great -----and after a good run time how does that packs voltage look? What fail safe settings are you programing into you 10X?? How about a good up elevator failsafe kick so you can see an airborne RF problem -----
Lee