For those of you who don't subscribe to the newsletter, or those that don't read all my my long missives, here's some info as a follow up to a post I made about Energizer Lithium batteries a couple of months ago. The original post: AA Batteries - which ones? explained why I have switched over to Energizer Lithium batteries most of the time. However, one regular blog reader had a go with them and discovered that they get rather hot in use in a flashgun, especially when shooting lots of images in a short time period. Becasue of this he was worried about over-heating.

Well, I went away and did some research on the matter and found out that there is no need to be worried. As it turns out, the Energizer batteries will become hot in use, that's just their nature, but because of this they do have a thermo cutout system for when they get too hot. Failing this, the Canon Speedlite 580EX II also has a thermo cutout switch which will power down the flash if it gets too hot. So, you can use the Energizer Lithiums without worrying about killing the flash - just be aware of them getting hot and if you're still not sure in use, take them out and give them a rest to cool off again.