Under the blazing sun during the start of the Le Mans 24 hours skating race I shot only two hundred frames before running my three freshly recharged batteries flat. I first thought that they were nearing the end of their useful lives, but during the night I managed to shoot four hundred frames on a single battery I just recharged. The intense heat from direct sunlight may have something to do with how fast power is depleted.

This comes as a surprise to me : I am used to rotating batteries in an inner pocket near my body to keep them warm in extreme cold weather but this is the first time I encounter performance degradation in extreme heat. And I have no idea how to attack this problem.

Robin Tichy mentions that “Li-ion batteries outperform their counterparts in high-temperature conditions ranging up to 40°–45°C. SLA and NiMH batteries do not perform well in higher-heat situations”. The BP511A batteries I use in my Canon Eos 300D use Li-ion – maybe I should consider myself lucky I did not use NiMH batteries