Originally Posted by
StephenH
One of the major issues I had using headlights that were rechargeable is that I would forget to plug the thing in when I came in from a ride, then wouldn't be able to ride the following day. If you used rechargeables for multiple rides, you'd potentially have similar issues, either you recharge every ride, or you find yourself waiting until they dim and then it's too late.
I usually just carry a spare battery. I charge the batter as soon as I take it off and it becomes the spare. If the battery is non-removable, I have a secondary alternative that runs just waiting. I'll charge that at the beginning of the season if it doesn't have replaceable batteries. For my bikes with dyno lighting, I have batter backups for tail light and headlight if I have a mechanical failure.