My fenix 5 battery life significantly decreased recently. It went from 65% to 4 % in one morning (7:30-1:30), with no GPS use. I just charges to 100% at 7:00 and at 11:10, it’s at 83%, again with no GPS use. Software version 25.00. Any solutions or help?

Soft-reset the watch (hold the Light button till the watch shuts down, and then restart), and wait a few days till the battery gauge recalibrates. Especially after firmware upgrades, it can happen that the battery gauge calibration data gets misaligned, and the new calibration (including some full charges and discharges) is done, before the gauge shows the true battery level.

There is also a recent issue with long Strava and Garmin Segment (> 20km) who trigger excessive Bluetooth communication, draining the battery fast. Disabling Strava segments (in the GC Mobile app » Menu » Training » Segments), or removing long segments from Favorites may then help.

Another possibility is setting the watch into the Do Not Disturb mode, and see whether the battery drain changes.

It could be, of course, also a hardware failure, the F5 is an old model, so it would not be surprising if the battery capacity deteriorated. Test the other options first, though.