For those of you who might be interested, I’ve created a 3D printable case for the 2015 SmartThings motion sensors that uses 2 AAA batteries instead of the a single CR2450 button cell. This provides 3x the capacity at a much cheaper price, so IMO it’s totally worth doing it if you -like me- hate replacing those costly batteries so often, specially after the last (awful) firmware upgrade that made these sensors drain their batteries even faster than before.
It might work for the 2016 model too, but I don’t own any so can’t confirm. Please let me know if you try that.
More details and pictures in the thingiverse page: https://www.thingiverse.com/thing:3212345