It might not have been practical to design it to accommodate two cells, but I think they made a huge mistake in the cell they chose. 10,000 lumens is going to require around 30A. Nitecore chose to maximize capacity by going with the 48G, but that cell is only rated for ~10A drain. So I’m skeptical it will actually hit the claimed lumens, and even if it does, using turbo is going to be very hard on the battery. They should have chosen one of the 3,000-4,000 mAh cells that can handle high drain. Sure, you wouldn’t be able to advertise as long of battery life, but it would be the better choice for battery longevity. Considering the battery is soldered in, avoiding premature battery wear/failure seems like it should be important.