This started with the last upgrade to OS 26.1. I wear it to bed and put it on the Apple charger when I get up in the morning. What used to take about an hour and a half now takes twice as long. It would occasionally only charge to 80%, but I haven’t seen that since the OS upgrade. I haven’t messed with the settings at all, and I’m wondering if there is anything I can do to fix this and if others are seeing it.
Apple instituted “optimized charging’ a while back. Your watch only charges to 100% occasionally, and the norm is 80%. They did this to prolong battery life, they say.
Actually, mine charges to 100% most of the time, and only 80% occasionally. And that hasn’t changed with the recent OS upgrade; only the length of time it takes to charge. Of course, it has always taken longer to charge to 100% the next morning for the few times after it charges to 80% the day before, but my watch is now on low battery mode in those instances. That suggests the new OS is may be using more power.
I also find that for the first few days after an OS upgrade, the battery usage on the watch is higher. I put this down to general cleanup and optimization. That said, the Liquid Glass features in WatchOS 26 may well take more power.
Optimise charging is a mystery to me. It can go from 20% to 80% in no time, or can take (seemingly) hours to go from 65% to 75%. I appreciate it can be turned off permanently, but I prefer to preserve battery life as much as possible.
The frustration is when it’s dropped to maybe 50% (overnight), and I have a lot of activity ahead. I’d like it to quickly charge to 100% so I know I can get through a full day ahead, only to find it ‘limited’ to 80%.
Bumbling into the deep dive of Battery Health settings to find the Optimise Charging switch is pretty annoying. I wonder if there’s a way to shortcut the ‘Turn off for one day’ option?
Interesting behaviour I saw this morning. When I woke after a good night’s sleep, my battery was at 93%. I took off the watch and put it on the charger — and after 45 minutes it was down to 87%. It actually reduced charge whilst on the charger.
I can only guess as part of the battery optimisation, it drains the battery to a certain percentage before topping up, but it seems odd behaviour.
I’d suggest instead that if you have the optimized charging setting turned on and put the watch on the charger while it is above 80% it will, in most cases, prevent charging of the battery. It’s not deliberately draining the batter - it’s simply not drawing current to charge the battery.
See this support article to see how to charge when the delayed charging symbol shows.
I see that off and on, but I’ve always blamed it on my not seating the watch on the charger properly (which may not be correct). I’m pretty sure my problem is due to some change or addition in WatchOS 26. I turned Nightstand Mode off just now to see if it will help reduce the morning charge time. It was in low power mode when I got up this morning. I recall seeing a 74% charge before I went to bed, but not sure that was last night. I am 82 and wear it to bed so that it will hopefully wake me up if it senses something not right. My doctor reduced my Atenolol because my heart rate was dropping below 40, and the watch was waking me up.
That’s seems reasonable, but I don’t believe it’s correct.
This morning my watch was at 93%. I was heading to the gym so I decided to put it on the charger for 45 minutes before I left. When I took it off the charger, it was at 73%. Nothing I could do in normal use would make it drop 20% in 45 minutes. In my mind, it’s deliberately draining it, presumedly in an effort to optimise charging.
I’d be much happier if it just did nothing and left it at 93%. I’m now inclined to turn optimise charging off permanently.
That isn’t acting the way that any of my watches have - I have never seen the watch discharge while on the charger - and I don’t think it’s designed to work that way, so I think what I would do:
- Power off and power on the watch.
- If that doesn’t change this behavior, purchase a new charger.
- If this doesn’t change this behavior, purchase a new charging cable
- Obviously, at this point you have a few choices:
- Unpair and re-pair the watch. You could try restoring a backup, but if this behavior isn’t changed after a couple of days, I’d even suggest unpair and then set up the watch from scratch.
- Or, of course, contact Apple for technical support.
You can probably reverse items 2 and 3.
I don’t think that optimized charging is worth using myself, as all it really does is reduce the amount of time I can use my watch before I need to charge it. I rarely charge to 100% anyway, as I charge only while I am showering, and sometimes when I am cleaning up before bed. Otherwise it is on my wrist. (Of course I do charge it while it is installing an OS update, as that’s required to install an update.)
I don’t know about “deliberately draining”, but “refusing to charge” is definitely real.
My phone (sorry, I don’t have a Watch) is configured for optimized charging. So it will charge to 80% quickly and then pause until morning.
I frequently play games in bed when it is on the charger. I’ve found that if the level is over 80% at that time, the level will drop (due to the gaming) until it reaches 80% and will then stay there until morning.
I’m not sure what is causing your watch’s battery to drop that rapidly, unless there is some power-hungry app. But if it was due to some kind of optimized charging, it shouldn’t have dropped below 80%.
My wife’s Watch sometimes fails to charge due to the magnetic charging puck not always making good contact. So she makes a point of waiting to hear the charging chime and see the screen change before walking away, and that hasn’t been a problem since.
Sorry if I can’t be more helpful, but that’s about all I can think of at this time.
For the record, after a one hour, high intensity fitness class at the gym, it only dropped from 73% to 67%. This compared to a 20% drop in 45 minutes on the charger.
My drone batteries will discharge before a full charge so it’s not unheard of in lithium battery recharge cycling. I’ve turned off optimise, I prefer to rely on my own reasoning to decide when I need a full battery.
A quick check with ChatGPT revealed thus:
Charging Protection / Optimized Charging Glitch
Apple Watch uses a feature similar to iPhone Optimized Battery Charging, which tries to slow or pause charging above ~80%.
Sometimes the watch:
- Stops charging at ~80–85%
- Tries to regulate temperature
- Gets “stuck” in a loop of charging → stopping → discharging
This can cause a net loss in battery percentage if the charger isn’t providing enough power during those cycles.
And this
A watchOS bug (confirmed by Apple Support in the past)
Several watchOS builds (10.3, 10.4, 11.0) had bugs where:
- Battery percentage reporting was incorrect
- Charging state would jump up/down
- Charging would intermittently stop
- The system would “reset” the battery level mid-charge
The watch is fully updated but it’s possible the issue still exists. I suspect I won’t see it again now optimise is off.