Chargers like a LaCrosse BC-700 can give you an approximate capacity measurement for a battery, you could use that to bin them into rough capacities and color c

Chargers like a LaCrosse BC-700 can give you an approximate capacity measurement for a battery, you could use that to bin them into rough capacities and color code with stickers. But if the charge time is changing that drastically, it sounds like more of a maximum current issue. I've been under the impression that NiMH batteries can deliver higher current than alkaline, but I've never tried them for something like a camera flash. EDIT - higher end chargers can measure the internal resistance, which I think is the number you need for issues with limited power draw. With a BC-700 you can apparently approximate this by using its discharge mode and seeing how a battery's voltage changes when you're drawing power from it. Discussion here: http://www.candlepowerforums.com/vb/showthread.php?338786-Quick-and-dirty-Internal-Resistance-with-the-BC-700-charger http://www.candlepowerforums.com/vb/showthread.php?338786-Qu... Or a BC-1000 will do it for you.