Originally Posted by
cyccommute
Second, carry a back up system or, better yet, get a second light. At $40 to $50 per unit for the double lamp and $25 $40 for a single lamp unit, having multiples isn't all that expensive.
Third, carry an extra battery if you don't charge it every night when you get home.
Fifth...boy, this options list is getting long...carry a backup to the backup. Even if you ride with dynamo lights, you should carry a backup of some kind. Stuff happens and it's a little known or, rather, a little appreciated, fact that it gets dark when the sun goes down.
Sixth...and not necessarily finally...I almost guarantee that if you forget to charge your battery and it goes out on the way home, you won't forget to charge it again. Experience can be a harsh mistress.
This is what I ended up doing. I wanted to get an 18650 powered xml light to go with the Magicshine and the Viz 360, and couldn't decide between the single mode and 5 mode. So I bought both (at $15 each it was easy) and some spare batteries too. I ended up with not only redundancy, but different lights that work better in different situations that allow me to reduce my worries about running out of charged batteries.