Battery drain on my Apple Watch after watchOS 9.5.2 update

15.5.1(c) is an iPhone software update. I would not expect that to change the battery performance for your watch. I expect a Watch update soon and I expect that to have a substantial change on watch battery life for everyone.

Watch face??? Did I “miss a meeting” somewhere?

Especially with the power usage pattern of only turning the watch on for a few hours between full charges, having the battery indicator do wonky things doesn’t surprise me. Lithium ion polymer batteries have quirks that are based on the physics of the underlying technology.

The next rabbit I’d pull from my bag of tricks would be to power cycle the watch from 100% charge down to automatic shutdown at least three times. Charge it completely, run it down to no charge, rinse and repeat at least two more times.

The first power cycle ought to be quite short, only a few hours based on your experience. The second power cycle may not be much longer or different. If my hunch is right, the third cycle ought to allow much improved battery life.

If the battery life improves, it still won’t be as good as it will get. More full power cycles will stretch the battery life a bit longer, just like regular exercise helps improve your physical performance. If the power cycle doesn’t improve the battery life, that will give us a nudge towards a different approach.

YetAnotherSQL wrote:

The next rabbit I’d pull from my bag of tricks would be to power cycle the watch from 100% charge down to automatic shutdown at least three times. Charge it completely, run it down to no charge, rinse and repeat at least two more times.

This is potentially damaging advice. Deep discharge of Lithium rechargeable batteries is not recommended by any of the major manufacturers. It used to be valid about 30 years ago when we all used NiCd, but never for Lithium.

Worst case, if you manage to discharge to 0% (zero) the battery might go into a safety lock-out and refuse to recharge. At that point the battery is useless and can never be charged again.

The recommended approach for Lithium batteries is to try and maintain them in the range between 20-80% charged, and my preference is to plan for recharge at 30%, which leaves me another 10% reserve for unexpected emergency use. Try to avoid going below 10% unless it is an emergency.

Re: Watch face. I thought the battery is not replaceable and that they replace the watch face as one unit. Caveat: My SME in Apple Watch repair is strictly from Google so that’s not worth much. :-)

I will take your advice on fully charging and then letting the battery drain to 0% a few time and will capture the metrics.

Yea. I’m bummed the new update didn’t resolve this edge case but thought it was worth a try.

@branta_uk does make a good point. Using “no charge” was an error on my part as I proofread. It seems ironic that the proofread introduced an error. I’m sorry for that.

I should have used “automatic shutdown” or “full cycle” like I did everywhere else in my post.

As a side note to @EBeth0001 continuing to use the Watch a few hours then recharge will progressively shorten the reported Watch battery life.

EBeth0001 wrote:

I did charge it to 100%. It’s been 16 minutes and it’s at 82%. I’ll let it drain to 50% and then power it down until I decide what to do with it.

My advice is to keep using the watch if possible. Put it back on the charger if necessary, but keep its alive and let it sort out its post-update tasks instead of shutting down and having to start over, and over, and over...

You won't do any real harm to the battery by leaving it on the charger for a day or so. The charging system on Apple Watch is intelligent, and it will just stop the charge to prevent over charging, and continue to use the charger power to run the watch.

I and many other users have noticed that battery usage is often much heavier than normal for a few days after a software update. We believe this is because the internal storage gets reindexed after the update is installed, and there is probably a lot of processor work to do this and clear all the remains of the previous version. Usually this clears after a few days and everything is back to normal. However, you need to let the software do its job and not keep making it go back to the start line by shutting down.

YetAnotherSQL wrote:

@branta_uk does make a good point. Using “no charge” was an error on my part as I proofread. It seems ironic that the proofread introduced an error. I’m sorry for that.

I should have used “automatic shutdown” or “full cycle” like I did everywhere else in my post.

No, DO NOT ever run Lithium batteries until their device shuts down. That's No, No Way, except if it is a life threatening emergency. The battery can't be "recalibrated" that is for different battery chemistry.

If you don't believe me, use your device for a simple test (use *your* device instead of risking other site users). Go into Settings/Battery/Battery Health and note the Maximum Capacity %%. Then do your Run to shutdown and recharge fully about 10 times, then check the percentage again and see how much it has degraded.

Since applying iOS 16.6 and watchOS 9.6, the battery life has improved. I can get 12 hours before needed to charge my watch.

Note, I was easily getting 16+ hours before the watchOS 9.5.2. I can say that with confidence because my stand goal was 16 hours and I usually met or exceeded that goal. Lol

Yes, I’ve unpaired my watch. I rebooted both devices. I wiped and reloaded my phone from backup. I’ve turned off all notifications, deleted all apps on the watch, turned on low battery mode, turned off Siri, etc. I have very few apps on my phone. I have noticed that when my watch gets into the state where the battery drains very quickly, the workout app is slow to load and doesn’t capture heart rate. I just rebooted both the phone and watch and still cannot get my watch to capture my heart rate.

This seems like a race condition that starts impacting functionality (like heart rate) and increases processing to the extent that the battery is negatively impacted (draining extremely fast).

Spent more time today troubleshooting why my heart rate isn’t captured. I cleaned the sensor and unpaired/repaired my phone. And confirmed all the settings and I do see the green light when it’s attempting to read my heart rate. Still cannot get the heart rate capability to work. Battery continues to drain excessively fast.

Similar here with Apple Watch 7. Pre-9.5.2, it would last for a good day and a half. Now I have to charge it twice a day. Wishing now I hadn't let it update.

But my watch battery is not lasting 18 hours - I have to charge it 3 or 4 times in a day... This can't be normal

See -> Apple Watch battery -> Apple Watch - Battery - Apple

diagnostic was normal and was linked to below

Apple Watch Battery and Performance - Apple Support