Originally Posted by
Tourist in MSN
I use NiMH rechargeable AA and AAA batteries for GPS, taillight, headlamp (for my head), I charge those off of USB power too.
I switched to 18650 for everything aside from few minor legacy items. The advantage is that the same batteries can be used in backup power for phone and laptop. They hold far more power per volume or mass, do not lose it and are less sensitive to cold. Some old laptop batteries can be opened to extract 18650 cells from them.