you will find that if you use the 2650 duracells you will get a little longer burn time in turbo mode if that is a concern.. I have found that the duracell 2650 to be very reliable while I have gotten some bad cells using the energizer nimh.. I have been able to get 2.4 hours in turbo mode, if you drop it to high mode you will get almost 5 hours of burn time..