Iphone 6s randomly shuts off.

my 6s dies on me too- this is by far the most unreliable iPhone I have ever had- somehow I think mine issue is related to temperature - last week is was about 38 degrees and the phone completely died with 35% battery remaining - it turned back on and then died again. I did all the diagnostic care stuff and talked to tech at Apple and did the text message diagnostics and they determined my phone was fine- took to apple store and they said phone was fine - the phone has died on me half a dozen times all in the 35 to 40 degree range while outside and at 40% or lower battery power- I really think the iPhone 5 and 5s where way better as far as reliability and stability goes (rant over)...

 

My 6S is doing this (it's done it on 3 separate occasions now). The most recent time, the iPhone just shut off as if the battery had totally depleted. It then showed the 'plug-in to power' screen… I was at home and went to put it on charge. The usual wait-for-a-few-minutes-before-it-starts-up routine was not necessary, as it started up the instant it went onto the lightning connector.
I then noticed it was showing 18% battery left. (A couple of minutes later, this had dropped to 9%).

Temperature doesn't seem to be a factor here; this was in England and the highest it got today here was 12ºC.

 

Wiat iOS version do you have installed? I just had yesterday same thing happened to me, when tried to record a video outside (temperature was about 10 Celsius). For a while turning low power mode helped although after two minutes of recording phone shut down, and was also showing plug in to power screen. Battery was about 50% charged and this was happening on current public beta, 9.3.2.

 

I have iOS 9.3.1.

Before, this kind of thing would have been purely an annoyance - but now with my 6S, I'm using it as both a bus ticket (quarterly bus pass for work) and as payment for drinks/food etc. when out & about with Pay - so it becomes a lot more important that my device doesn't just cease unexpectedly.

I do wonder if it might be software, as I've not experienced anything like this since I got the 6S at launch - until now (having recently moved to the latest iOS)…

 

Tell me about it, I lost some nice video footage from launching sailing yacht just yesterday, it was very annoying. I think this may be software related, as I experienced this kind of behavior only once in the past, on iOS 9.0.x or 9.1.x, I don't remember exactly, it beginning of November.

 

Never happened to mine. I've only had it for a month though.

 

I would get it replaced, honestly. That doesn't sound normal at all.