I love Magicshine lights as well but have concerns about the quality. For that matter no light is 100% reliable and like you I always carry a backup light.

I can only guess at the issue with your light. I find that sometimes it is difficult to make a solid connection. Is it possible that last time when you charged it up you didn’t have a good connection and did not charge it up at all? I verify the connection to the charger by unplugging the charger and plugging in the battery. If there is a good connection then the current in the battery turn on the LED in the charger. I then gingerly plug in the charger and let it charge overnight. Just a thought.