I shoot events, so keeping track of batteries on shoots is super important. I 3d printed a battery case to hold my batteries but I still didn’t have a way to keep track of which ones I used and which ones needed to be charged. I was thinking of some sort of door or clip system, but I settled with an old school simple way of slotting the batteries in the case. I painted a green dot and a red dot on the batteries themselves, and when one is finished, I load it in the case red dot up. Easy way of keeping track of which battery is low and then I can charge them when I get home.