Using it to hold 15 of the QC 6 Cell 10,000 mAh batteries. However, it is heavy. Thinking of having a smaller one made as well to use to transport 2-4 batteries to wherever I am flying from - certainly do not want to drag a case this size everywhere if I don't need to. This is not a Pelican Case (although they do have them). The dimensions of this one seemed best suited for keeping the batteries standing up and keeping the battery depth within the height of the base of the case - allowing the lid to press down on them to hold them in place. The case brand is Boyt (water proof, crush proof, etc) and with the custom foam it was about $200.
Sorry, forgot to mention that it came from www.mycasebuilder.com. Their online software makes it really easy to design your case the way you want it - and the dimensions of the cuts were just the way I had spec'd them out.
I do not travel with it so I opted to find a case without the wheels as to not cut into the interior depth where the wheels go. However, you can make this style of case from just about any pelican, storm, or any other cases out there. They sell most every case you can think of. Then, just measure your batteries and lay out a case that suits your needs. Its really easy. Here is a link to the one I picked to do QC 6 cell 10,000 mAh batteries: http://www.mycasebuilder.com/bt-h20-custom-foam-case.html
This is still my favourite battery case - http://forum.freeflysystems.com/index.php?attachments/c43c9181-jpg.943/