I use a couple dozen Eneloop batteries to power my 580ex's. For most weddings, I only have to change them out once on each unit. But occasionally wedding halls will be especially dark and the unit will have to work harder than normal so I'll end up having to switch them out a few times each. A dedicated battery pack just isn't an option since one of the units is usually on a stand across the room. I've been faced with a problem for some time now in charge management. Since sometimes I have weddings back to back on Fridays and Saturdays I don't have a few days available to get all of my batteries charged and ready to go. Not to mention keeping track of what is charged and what needs to be charged can be tricky. So, I'm wondering, those of you who power your flash with rechargeables, what's your method for managing the charging process on them?