I don't mean a rig that uses both packs at once, but rather, for long rides, using high levels on your front light, do any of you ever use (or bring along) an extra battery pack? If so, does it have a negative effect on the light itself if used for long periods of time? In other words, should the light "rest" after the battery is complete or is it fine to be on high (if needed) for up to 3 hours a day? I mean I get that the more you use something, the shorter its lifespan, but I wonder whether using two packs one after the other with no break in between is overload or not. Thoughts?