@alex24 nice! How do you handle opening and closing? Do you always unscrew all the screws?
Yes, you need to unscrew all of the screws in order to access the battery. However you don't need to put all 4 screws back, 2 is enough . Alternatively, instead of screws you can secure the shell using some rubber(silicone) rings(or something similar).
What exactly are you aiming for with that mod?
I made this mod in order to have an option for easier battery replacement if needed. If I'm going somewhere and Crafty is not charged - I can easily swap the batteries and go. Or I can have a few pre-charged batteries if I'm going somewhere where charging is a problem(camping, hiking, etc.).
Another reason was to use better quality batteries with Crafty. For example Sony VTC6 works better than stock battery - 10-15% faster heat up time, battery charge lasts about 20% longer.