Thank you for your reply.
Indeed, that would be a solution, but it would take quite a lot of time to make and a constant quality for a small series would be hard to obtain.
Another solution would be to find "some box" which happens to have the right volume and adapt it where needed.
But I'm looking for a finished product, where I would just have to insert the completed battery pack, with a decent connection system that will survive daily connect/disconnect to recharge, so not with some cable and plugs that will get a bit looser on each reconnection.
I would be able to do what I want with a modified "frog" case for example, but those only seem to exist in 40 cell volume, I would like to save the 25% volume.
The goal is to have a bag which has a compartment with the connector in it, where I just need to slide in the battery, making it connect once it is all the way in.
A strap could be keeping the battery in place, for example.
The remaining space in the bag will be used to transport other random objects, so the smaller the battery, the more room will be free for the objects.
