A small 11-12MB update was installed on my S3 Frontier this morning from a full charge.
This update has killed my S3. It has gone from 100 to 12% battery in about get in 4 to 5 hours with normal use.
Prior to this I was getting about 2ish days of use between full charges.
I had the same problem with my Gear s3 Classic. I broght them home, installed many aplications, watch faces, games.. And my battery dropped from 100% to 20% in 4 hours. So I tried:
The battery life became amazing. After a work day I still had at least 75% of battery. So I tried to install back aplications to my watches in small groups and test battery life. After all aplications installed the battery life were without change. I´m not sure where the problem was but now it is solved and I can fully enjoy this amazing watches.