"no cell coverage" is draining my battery.

I'm in Europe, without international cell/data coverage through my carrier. I've had my 5c in Airplane Mode since taking off two weeks ago. Abruptly 3 days ago, my battery began draining excessively with minimal actual use.

I've done all the troubleshooting tricks: restarting the phone, eliminating Background App Refresh, updating to the latest IOS (9.3.3), turning off Location Services, turning off automatic updates, turning off the iCloud keychain, putting the phone in Low Power Mode, etc. I deleted Google Maps because it was the most recently updated App.

I'm still having issues with battery drainage. Yesterday, my biggest drain (60%) was from "no cell coverage."

Any idea what could be trying to access the cell, even though i've got the phone in Airplane mode, and how to resolve this issue?

It's a new display setting in iOS 9.2. When cell coverage is weak the phone increases its output power in an attempt to maintain a connection. A weak signal uses 10 times as much energy as the strongest signal, so it can drain a battery very fast if you are on a call, and it will still drain the battery when not on a call because the phone periodically reports its location to the network so an incoming call can find your phone. To further complicate things, if you periodically lose signal completely the phone sends a "where are you?" page to the network to reconnect. This is sent at full power. If there's no response it repeats the request periodically, with longer and longer waits between pages. However, if it reconnects and then loses the connection frequently, the pages are sent frequently without the longer waits, again draining the battery.

All cell phones work this way, including the iPhone. In the past all of this happened behind the scenes, so you didn't know about it other than the fact that your battery doesn't last as long in a weak signal area. With iOS 9.2 (and possibly 9.1) the Battery monitor now tells you about it. You will only see it if it uses more than 1% of your total battery usage.

Also, note that the battery display is a percentage of a percentage. That is, that 60% means 60% of the total battery usage over the past 24 hours, not 60% of the battery's capacity. So if your phone used 50% of the total battery capacity (the top bar display says 50%) that means that "no cell coverage" used 60% of 50%, which is (0.6 x 0.5) 30% of the total battery usage for the period.

ADDENDUM: If you tap on the display at Settings/Battery it will display the actual time that each app consuming energy spent running in foreground and background.

I had the same problem with my battery dying too fast using an iPhone 5 with iOS 10 as a wifi only device. I found turning off location services in Settings helped a little, but the biggest improvement in battery life came from putting the phone on AIRPLANE MODE, with wifi turned on. Then the battery usage shows only apps I am actually using.

You're not the only with this issue. As soon as I updated to 9.2.1 I the "no cell coverage" app completely drains my iPhone 5s battery whenever I'm in a poor/no-coverage area in just a few hours.

Clearly this is an issue related to 9.2.1 because this issue did not happen in 9.2 and earlier and does not happen to my identical iPhone 5s that is still on 9.2.

To make matters worse, I have found that disabling cellular in Settings is not a fix. The "no cell coverage" app still runs and still drains the battery. This is actually quite maddening.

I paid a lot of money for my iPhone, Apple. It should just work.

Sorry, but I disagree. With WIFI calling my phone does everything it could do if it had a cell signal. Why should it constantly check for a cell signal? The whole point of the feature is to make calls and texts when you don't have coverage. Why should I have to remember to turn airplane mode on and off?

I have this same issue except in my situation I have WIFI calling (T-Mobile). Even when I have strong WIFI signal and can make and receive calls and text messages, "No Cell Coverage" is always my #1 app under battery usage.

rohamner wrote:

Sorry, but I disagree. With WIFI calling my phone does everything it could do if it had a cell signal. Why should it constantly check for a cell signal? The whole point of the feature is to make calls and texts when you don't have coverage. Why should I have to remember to turn airplane mode on and off?

Because that's the way cell phones work. They look for a cell signal as long as they're turned on unless you put them in Airplane mode.

See my response below.

Turning everything off isn't going to help much. What differences are there between the phones? For example, does yours have a metal case on it that could be blocking signals? You might also have a failing battery; if you can take it to an Apple store they can test the battery.

rohamner wrote:

I have this same issue except in my situation I have WIFI calling (T-Mobile). Even when I have strong WIFI signal and can make and receive calls and text messages, "No Cell Coverage" is always my #1 app under battery usage.

Having a strong WiFi signal is irrelevant. The issue is that you have a poor cell signal. Turn Airplane mode on then re-enable WiFi.

rohamner wrote:

I have this same issue except in my situation I have WIFI calling (T-Mobile). Even when I have strong WIFI signal and can make and receive calls and text messages, "No Cell Coverage" is always my #1 app under battery usage.

But when your phone is asleep WiFi is off, so the phone reverts to cellular. And if you have no cellular signal the phone will keep trying to reconnect to the network, draining the battery.