Significant battery drop/reboot, but only in cold weather (+5°C/+41°F) with camera - expected behaviour or battery defect? Disclaimer: This is not a duplicate, I've looked at these questions but none are applicable(temperature) or provide an adequate answer.
Recently I've realized that my 15 month old LG G4 seems to have an issue with the battery in cool or cold weather: dry, no significant windchill, +5°C/+41°C
In at least 3 instances, it happened to drop from 50% or even 65% charge to zero, rebooting without warning. I've not seen issues at other times (higher temps)
I can even reproduce this:

Have the phone at 50% to about 70% charge
go outside if its around 5°C
take a couple of pictures with Open Camera.

After a couple of minutes, it will reboot and only have a fraction (&lt;10%) of the charge, and keep rebooting if I try to take pictures.
I've tried all the &quot;battery reset tricks&quot; out there, but as I said above - I don't have any issues other than in the cold (+camera).
Is this expected behaviour or should I replace my battery ?
Do I want too much from my smartphone ?
Should I scale back my settings to try and keep the power draw lower ?

Additional Information:
It's a Li-Po 3000 mAh (original) battery
Android 7.1.2 (LineageOS 14.1)
Open Camera settings: High Res (16:9 15.87 MP), 90% JPEG, GPS on, 100% display brightness, background thread, no flash
I'm also uploading the pictures to owncloud via the owncloud App (&quot;Instant Upload&quot;) over 3G/4G
Here are some graphs from GSam Battery Monitor.
If you look at them closely, it seems to &quot;recharge&quot; around 5% if its in a warmer environment again.
All batteries achieve optimum service life if used at 20°C (68°F) or slightly below
For Li Ion ( or Li Po) the ideal charging temperature is 0°C to 45°C
(32°F to 113°F) and operating temperature is –20°C to 60°C
(–4°F to 140°F) Source


Based on the above, it looks like you have a poor battery given that


It is being operated within the designed temperature range
Unexplained sudden drop from above 50% or more to zero
Marginal increase in charge when brought indoors


Till you get a replacement battery all I can think of by way of power consumption reduction is to delay the cloud upload (do it once it's charged / WiFi)

Edit: Try a different camera app. It looks like Open Camera does consume more power and show increase in battery levels after reboot as quoted here -in particular post of 17/12/2017 which matches very closely to what OP describes. If that doesn't help much change battery