I made some tests during the last days and I found what causes that heavy battery brain on my Fenix 5s.
I used the following widget to take my measurements https://apps.garmin.com/fr-FR/apps/5e49aebc…
from a week I installed the fw 12 ... my watch is reborn ... currently I am at 60% of autonomy and it is from last week that I do not load it since I installed the fw (and it was 90%).
Fenix 5s with new firmware 13.30
Still the same. Battery drops very fast. 60% per day.
Even after an hard reset and removing all watch faces and widgets...
Just like with the firmware 13.00, my watch is not visible when plugged to a computer. It worked with previous version. I can't downgrade.
Just a suggestion, because it has happened to me, that the PC not recognising might be due to a poor cable connection rather than the firmware. I found that the watch would charge, but the PC wouldn't connect to it. So I looked at the USB cable and sure enough one of the pins was 'stuck in' (They have little internal springs). Cleaning the cable so that all the pins came out to the same extent fixed it.