Most photographers have several sets of rechargeable batteries; typically at least two sets for each of their portable flashes (or other gadgets or cameras that use AA or AAA batteries). This becomes a management issue because they bang around inside the bottom of the camera bag and it’s difficult to know which batteries are charged and which ones are dead.

I have an easy two-part solution:

1. Organize Your Batteries in Sets: These clear plastic cases for AA batteries are perfect for keeping rechargeable batteries organized into sets. At less than $2 each they are very inexpensive, and since most electronic devices use batteries in sets of 2 or 4, they hold just the right number of cells. They are also available for AAA batteries and in larger sizes in case you want to hold more than 4 batteries.
2. Carefully Arrange the Batteries in the Case: Most devices that use AA or AAA batteries must be loaded so that the orientation of the positive and negative terminals for adjacent cells alternate. If you always load your cases with freshly charged batteries so that all 4 cells are oriented in the same direction, and load cases with dead batteries alternating, you can tell with a quick glance whether each case holds fresh or dead batteries.