9.00 Software Update Battery Draining Rapidly

Same story here. But I found out that if you keep your wacht charging for about one hour longer than needed the battery drain seems to be better than when you don't charge the battery fully. I have the impression that it drains more rapidly if you charge it till let's say 95%.

So my suggestion would be to make sure you charge it long enough.

I also notice the same issue with my fr245. Before the update it can last about 7 days. But after the update, it only last about 3.5 days.

As they say below.  Over charge by 1 hour.  If that doesn't work a a complete System reset and overcharge should fix it.

Opposite here, I've been getting very great battery life lately. I have turned off pulseox and installed this watch face https://apps.garmin.com/da-DK/apps/40d76b53-8833-4c73-acd2-c4f1702145fe. I wish the original analog watch face could disable the second hand, then I would prefer using that.

Same issue for garmin fr245m

1 % per hour only? Consider yourself lucky.

Having this same issue. I've tried restarting the device, charging it for longer than needed and battery still only lasts for about 2.5 days. All battery saving options turned on as that's my normal running procedure. 

System Reset is the key.