I use rechargeable AAA batteries in my PDW Radbot 1000s. I run two of them flashing. I don't commute every day, so I just swap the batteries for fresh charged ones every couple of weeks. I run them day and night. Also a steady on tail light powered by my generator hub. I'm really not paranoid, I just ride all the time on rural 55 mph roads. Even a Planet Bike Superflash (hope I got the model right) is visible from over half a mile away into a rising sun. I look for stuff like that when I'm driving: what helps me to see bicyclists.