[MetalMan]

Brian, here's an idea for you - if you could fit a 2s Lipo in the battery tray, grab a 5v switching regulator and hook it up to the 2s Lipo with a switch between the two, and plug the regulator into the DX3R's battery input. You could also throw a low-voltage buzzer alarm onto the switching regulator's input that is set off at 6+V. Then you can have a Lipo-powered DX3R that won't receive too high of voltage due to the switching regulator, with huge runtime compared to the batteries you have in there right now, and no chance of over-discharge (assuming you don't accidentally leave the regulator on and cannot hear the buzzer). And if you currently have rechargeable AAs, then you won't have any self-discharge to worry about!