Speaking of rechargeable batteries, I just put the cheap batteries that came with my 1W Bike Planet Blaze headlight on a meter and they are still at 60%. They were supposed to have 5 or 7 hours run time on them. They must have 30 or 35 hours on them. I put a charger at my bike stand at home and another in my office and haven't touched those batteries yet.
I had to check. It's going to be dark when I get off work tomorrow.