so i finally started trying to use my 580ex at the end of last year and learn more about it. While i did learn a little, i ate up a ton of batteries doing it. I now have 8 rechargeable batteries, which is generally fine for going to a car show, a family gathering, or small photo shoot. But doing something like shooting a race kills them fast and i dont have enough time to swap batteries, charge them, and swap again a little later. So im looking for a battery pack that is going to give me the power i need but not be a huge monster sitting up on the wall. Anyone have some good suggestions on a line of battery packs, or a company to look more into?