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.
My SN 53 FT is updated to v13.30 and get about 8-9% per day average in just normal watch with Bluetooth connectivity and back light on 100% for 8 seconds set to "on after sunset". All other setting are pretty standard tracking the normal stuff (steps/HR/sleep/etc). GPS reduces battery life but only as expected. I use a external Garmin HR chest moniter ANT+ for all of the training tracking as it's far more accurate than WHR but this doesn't seem to affect battery life.
This is my 2nd F5 as the first one had really badly corroded charging contacts after 8 months, replaced by Amazon for a new unit as Garmin only offered me a refurbished unit.
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.