My Fenix LD2 and Cateye EL 530 both have dimmed on my during my regular ride home the last 2 times I've used them, and it hasn't been that cold here either. Temperatures were in the upper 40's last night, and in the mid 30's the time before that. I'm using freshly recharged batteries in the Cateye, and used both nonrechargable and rechargeable batteries in the Fenix. Both times the lights noticeably dimmed when outside, but worked much better after they warmed up when inside. I don't remember this happening before, is there something I can do to prevent this?