Hi, I have quite a few smartthings sensors and I got tired of constantly having to change some battery.
The smartthings batteries are 3v with ~200 or 1000mAh.
This solution has 15,000 to 20,000 mAh.
Here is what you need:
Just use two regular C or D Batteries
Soapbox for D-Cell:
Soapbox for C-Cell:https://www.rei.com/product/695993/coghlans-soap-holder
Solder the battery holder to the smartthings sensor. plug in the battery. Hot glue it into the soapbox, done.