Here's the problem with the Light & Motion Urban light series design.
The dust cap for the charging port is made of hard plastic polycarbonate, not flexible rubber or silicone. If you have a visor on the front of your MTB helmet- that's the same material form with this cap is made. It's fixed to the metal housing at one end. In order to open it one must bend it back along a horizontal crease or "hinge" (circled in red). In the photo you can appreciate that the plastic crease has begun to fray and deteriorate from fatigue due to repeated opening and closing. This is to be expected if one repeatedly bends a hard material at the same spot - we've all done with with a paper clip.
On this-particular light the crease / hinge has nearly degraded, due to fatigue, and only a small bit of it remains intact. After a few more charges, it will completely beak off and I will have to replace it with a fresh one. Which might last me six months (I ride every day to work and always use a front light).
An additional problem with this design and choice of material for the cap (hard plastic versus soft rubber) is that it cannot possibly provide a water-tight seal against the lamp's metal housing. The plastic cap edge does not conform to the charge port opening as tightly as it should - two hard surfaces won't seal against each other as well as a hard and soft surface would.
Until Light & Motion changes the design of this charge port cap, I advise against them. You'll be waiting for the cap to break off and then will need to replace it with a new one. Over and over again.