Iphone 6s shuts down at ambient temperatures

iPhone 6s 64GB.

My phone switches off at outside temperatures where I most certainly would expect the phone to work flawlessly.

This is a log I have kept on the occurrences and my troubleshooting.

First occurrence:

January 20th 2016.

Outside temperature: -10 Celsius.

Battery Charge: Approx. 40%

Phone kept in jacket pocket and is cooled to ambient temperature, not kept warm by body heat. (this is the same for all occurrences.)

Used snapchat, and chat program, took two pictures with snapchat and one with camera app. When taking a second picture with camera app the phone died, and would not switch on.

I was not surprises that happened due to the temperature, but this is not uncommon for Norway in the winter. To be on the safe side I went to an Apple reseller and ran a diagnostic, no issues found.

Was told to do a «battery reset» by fully discharging and charging twice.

This was done over the next few days.

Second occurence:

January 28th 2016.

Outside temperature: 7c.

Battery level: Approx. 40%

The phone shut down in the middle of a panoramic picture.

Unable to switch the phone back on, Battery depleted indication on screen.

A few minutes later the phone switches on but shuts down just after I input my code, battery level shows 33%.

Left the phone off until I get home, Once home I switch it on, it shows 32% battery level, and switches off before I can complete entering my code.

Charge the phone, and check Apple support page.

By advise from support page I did a factory reset, and recover a backup via iTunes and change it to 100%.

Third occurrence:

March 7th 2016

Outside temperature: 6c

Battery charge: 43%

Phone shuts down in the middle of a panoramic picture.

Will not switch back on, displays depleted battery symbol.

Return home 30 minutes later, but still get the depleted battery symbol.

Plug in the charger and the phone powers up with a battery status of 39%, after 5 minutes in the charger I disconnect it and the phone works just fine.

I do a diagnostic via the Apple support page, and call tech support.

I am given a case number

The diagnostic showed no fault on the phone.

My case was similar to issues other have experienced, but I had been more attentive to details than others, sadly she had no remedy for my issues, but encouraged me to keep logging further issues.

So I decided to do my own investigation to try and replicate the issue.

By placing my phone on my terrace for approxemately 30 minutes a time I cooled the phone down to ambient temperature at various battery levels to see how the phone responded.

Test 1:

March 7th.

Temperature: 6c

Battery charge: 35%

Phone shut down within a minute, did not use the camera, but e-mail app, iMessage app and scrolled within those apps.

The phone switched on by connecting it to a charger and displayed 35% charge.

March 8th.

Test 2:

Temperature: 5c

Battery charge: 89%

When I started using the phone the battery charge was 77%.

I opened various apps, like e-mail, iMessage, Facebook and camera.

After a minute the charge was 73%

After 3 minutes it was 70%

After 5 minutes it was 67%

After 15 minutes it appeared to have stabilized at 66%, at this time the phone was near room temperature.

Did a restart and it came up with 78% battery charge that dropped to 75% within a minute and stabilized.

Test 3:

Battery charge 75%

When starting to use the phone it had dropped to 65%, this dropped to 61% within 5 minutes of app use.

45 minutes later it was still 65%.

10 hours later on standby (Wi-Fi and BT active) it was 50%, which is totally acceptable.

March 9th.

Test 4:

Temperature: 6c

Battery charge 48%

When starting to use the phone the charge had dropped to 31%.

Used e-mail app, iMessage app and Facebook for 3 minutes without any issues.

Battery charge is 30%, Then I open the camera app and the phone shuts down.

2 minutes later I try to switch the phone on, but get the battery depleted symbol.

1 minute later the phone switches on, but shuts down when the input code screen comes up. Attempt to switch it on just gives the battery depleted symbol.

Hold the phone in my hands to warm it up for 1 minute.

Switch it on, gives a battery charge of 45% which drops to 41% within 3 minutes, an hour later it is still 41%.

Use various apps and camera app with no issues.

Based on this I suspect the issue is related to temperature and battery status.

It is possible that starting up certain apps, like the camera app, demands so much power that the battery’s reduced capacity due to the the temperature causes a voltage drop sufficient to trigger a shutdown. Once the temperature increases the battery capacity is restored and the phone powers on and works normal.

I would not consider 5-7degrees C to be a low temperature, and would expect a phone to work under these circumstances.

Somewhat below freezing I accept that this can be an issue.

Just for information.

I have a background in electronics, 9 years work experience on airplanes as an Avionics engineer, and 9 years with automated oil drilling systems so I consider myself to have a good knowledge of electrical components and systems.

Best Regards.

Egil.

Norway.