I have the same type of Tri-Cree (GB) with Obsidian lite setup with 4 rechargeable NiMH AAA batteries on my reaper and get 1 hr continuous use just like you. That seems about the norm for our setup.
Really? Dang, that sucks! I guess if I were to go to a convention where it's full of noisy crowds, I'd be better off with a no sound saber since it would last longer, and the crowds voices overpowers the saber's speakers. I guess my Obsidian Lite saber is better off for personal home use.
So if our sabers last 1 hour, then how long does the Emerald and Diamond versions last if their soundboards are more advanced? Or maybe there's not much difference.