Become a MacRumors Supporter for $25/year with no ads, private forums, and more!

acts4:12

macrumors newbie
Original poster
Nov 22, 2016
14
12
Hey guys, I have a Cellular S6 on the latest 7.4 Beta. It is connected to an 11 Pro Max.

I have noticed massive battery drain at night. Like sometimes 50% in a regular 7 or 8 hr sleep session. The strange thing is, during the day the battery lasts like a champ and seems to do extremely well. It seems like there is something during the night that is causing excessive drain.

I do use the "Sleep" function at night. I do wear my watch somewhat loosely, so i'm wondering if possibly the Blood Oxygen or heartrate sensor keeps running because it's not getting a good reading? What do you guys think? Anyone else experiencing this?
 

G5isAlive

macrumors 65816
Aug 28, 2003
1,271
1,923
I would suggest you do the experiment.. don't use the sleep function but put the watch next to the bed. My guess is your power drain will vanish. And I do think you are right, the sensors which project light are likely to be struggling. I dont have experience with sleep. How is the phone signal in your area. the thing I have noticed is batteries tend to drain faster in areas of weak signal. perhaps your bedroom is shielded? grasping at straws sorry.
 
Comment

acts4:12

macrumors newbie
Original poster
Nov 22, 2016
14
12
I would suggest you do the experiment.. don't use the sleep function but put the watch next to the bed. My guess is your power drain will vanish. And I do think you are right, the sensors which project light are likely to be struggling. I dont have experience with sleep. How is the phone signal in your area. the thing I have noticed is batteries tend to drain faster in areas of weak signal. perhaps your bedroom is shielded? grasping at straws sorry.
Thanks much for the reply. I appreciate it. Yeah, i'm going to have to try not using it and see what happens. I don't think it's related to the cell signal as I'm always on WiFi at home. I'll try tonight a couple of things and report back.
 
Comment

waw74

macrumors 68040
May 27, 2008
3,960
536
I don't think it's related to the cell signal as I'm always on WiFi at home.
if your phone is close, the watch is on bluetooth to the phone, And the watches wifi and cell radios are powered off.
so low cell signal would cause power drain on your phone, but little to no difference on your watch. (and if your phone has good wifi, then the cell shouldn't eat too much of the phone's battery.)

But if your phone is out of BT range while you sleep (or if your phone is off or in airplane mode), then the watch's wifi radio will come on, which uses more power than the BT.
then if the watch can't find wifi, it will power on the cell radio.

If it doesn't bother you too much, you could try a night or 2 with the watch band a little tighter.


If you go into the health app on your phone, and select "show all data" towards the bottom, you should be able to see each heart rate/Ox reading, and the time it was taken. I don't know how often it should update, but you should see a pattern of "every 10 minutes" or something similar. Compare that on different nights with how tight the band is, If the time between changes dramatically, then it's probably the sensors repeatedly trying and failing that's eating your battery.

I have a S5, so no Ox, and I don't use apple's sleep, so I can't help with what the timing should be.
maybe others can.
 
Comment

perezr10

macrumors 65816
Jan 12, 2014
1,327
577
Monroe, Louisiana
I’m not sure about your specific night time issue. But the blood oxygen function is a known big battery user. I’ve been watching YouTube battery tests that show the SE gets better battery life than the 6 unless you turn off blood oxygen testing.
 
Comment
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.