Apple Watch series 9 massive battery drain after OS 10.4 update

I updated my Apple Watch 9 (wifi/sim) last night, from fully charged to 40% in 7 hours whilst sleeping. Rebooted it seemed to make no difference, can literally watch the battery go flat.

This happened to me too last night. I noticed battery level had got significantly low early evening. Which seemed unusual. Charged it back up before going to bed. By the morning it only had 6% batt life left.

I have recharged it again this morning and so far it seems to be holding its charge...fingers crossed that it was just one of those things.

Series 8 here, but the same issue. Usually my watch will not even be close to dying with a once daily night charge. I had to charge my watch 3 times yesterday. Last charge at 01am to 100%, woke up this morning at 8am with a dead watch. My battery health is 98%.

I’ve unpaired the watch from my phone, I’ve done a hard on and off and let it run all the way down and recharge. None of the usual battery tricks seem to be working, it seems pointless to use my watch at the moment when I know in a few hours it will run out of charge.

Since this update, I’m dropping from 100% to 10% in 3 hours on my series 9. Ironically had the SAME ISSUE on my series 5. Support was useless, just wasted countless hours of my time until I gave up and bought the series 9. I am livid right now.

I've been having the same problem. My watch doesn't last 24 hours, closer to 18 or less...AND it gets very hot when charging. This all occurred after the last update, 10.4. Hoping that the fix is released soon.