How much battery life does No Cellular Coverage consume for your iPhone?

TidBITS Talk
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For the last few months, I’ve been tracking my battery usage because I have the feeling that my iPhone 15 Pro’s battery runs down faster than it should. I can generally go without charging during the day, but if I use GPS mapping for a long car trip or the like, I’ll almost certainly run out of power before the end of the day. To be clear, I think this has been happening since I got the phone, but it took me a few months to realize it.

I believe the culprit is No Cellular Coverage in the Settings > Battery list because it’s almost always in the top three or four items. If I don’t leave the house or use the iPhone for something like Continuity Camera, No Cellular Coverage will almost certainly be the number 1 or 2 top power consumer. In the last month, it has been in those positions for 14 days, and on those days, it accounts for between 10% and 35% of the battery used. Unfortunately, tapping that entry doesn’t reveal how many minutes it was “used” for, like apps. And it’s always the top consumer in Last 10 Days (right).

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Part of the reason I believe it’s the iPhone 15 Pro is that Tonya’s third-generation iPhone SE doesn’t even show No Cellular Coverage for most days, and for the Last 10 Days, it’s only 4% of her battery usage and way down in the list.

To be fair, the T-Mobile cellular coverage here is weak, but I don’t remember my iPhone 14 Pro having this issue, and Tonya’s iPhone SE does not. So it feels like it’s something related to the iPhone 15 Pro. To ensure that it’s not settings, I have:

  • Toggled airplane mode on and off
  • Restarted the iPhone
  • Settings > General > Reset > Reset Network Settings
  • Settings > General > Erase All Content and Settings and restore from backup

There are occasional days when No Cellular Coverage barely makes a dent in my usage, and those are generally when I’m not home all day. Spending the day in Oswego, NY for the eclipse, for instance, No Cellular Coverage used only 2% of battery life and was 13th in the list. Ironically, at least the speeds of cellular at the park we were at was terrible—things could barely load. But when I visited my sister in Woodside, CA over Christmas, No Cellular Coverage remained the top battery consumer. I don’t know how good the coverage really is there, but I would assume better than rural New York.

I’m planning to call Apple support about this, but honestly, I’ve been planning that for months and haven’t done it, so I figured I’d post here and see if anyone had any suggestions for things I might not have tried or that might explain why just this iPhone has such problems with No Cellular Coverage. And I’m curious if anyone else sees this problem, either with an iPhone 15 Pro or another model. Look in Settings > Battery > Last 10 Days and see what percent of your battery is consumed by No Cellular Coverage. Can anyone beat my 17%? :slight_smile:

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No Cellular Coverage doesn’t appear on my phone (a 13 mini) at all. I assume this is because Northern Virginia has really good coverage and my (Verizon) phone is never without a signal - except when I go to the movies, where the building seems to block everything. (Or the 13 doesn’t track this value.)

As for why it should be a big battery drain, it makes sense to me. Cellular radios tend to boost their gain in order to find a signal. If there is no signal to be found, the radio’s gain will be maxed out, and the radio is probably one of the biggest power drains in your phone. I think Wi-Fi is similar.

Although I don’t have numbers on hand to back this up, I have absolutely seen massive battery draining on all my phones if I spend time in a location with poor cellular coverage. When I remember to do so, I set my phone to airplane mode in these situations in order to preserve my battery. When I forget, I usually end up without much remaining power.

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Oh, yeah, I should have mentioned the gain boost in response to weak signal, and that makes sense to me too. But why would my fancy new iPhone 15 Pro have the problem where Tonya’s aging iPhone SE does not?

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Does Tonya’s phone support 5G? If not, perhaps it’s a 5G signal issue.

I’ve had my 15 Pro (Verizon) for less than two weeks. So far I haven’t noticed unusual drain, and there is nothing under no cellular coverage even for the last ten days, and that included time in rural Vermont and NH for the long weekend last week. But my summer house is in a cellular sink hole; I have a Verizon network extender there so it’s generally ok at the house, but go outdoors and my old 13 Pro simply suffered. I spent last summer with low power mode on almost all of the time just to get through the day.

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For the iPhone SE, MacTracker says:

5G NR, FDD-LTE, TD-LTE, UMTS/HSPA+/DC-HSDPA, GSM/EDGE (support varies by country) 5G (sub-6 GHz) with 2x2 MIMO, LTE Advanced with 2x2 MIMO and LAA

And for the iPhone 15 Pro:

5G NR, 5G NR mmWave, FDD‑LTE, TD‑LTE, UMTS/HSPA+/DC-HSDPA, GSM/EDGE (A2848) 5G NR, FDD-LTE, TD-LTE, UMTS/HSPA+/DC-HSDPA, GSM/EDGE (A3101, A3104, A3102, support varies by country) 5G (sub‑6 GHz and mmWave) with 4x4 MIMO, Gigabit LTE with 4x4 MIMO and LAA (All models)

So there’s definitely a difference. I don’t think there’s anyway to force an iPhone to a lesser network protocol, though.

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You might want to have the hardware on your phone checked out. Many years ago my mom (I don’t recall which generation iPhone) suddenly had terrible problems with her cellular connection and we took it to Apple Store and it turned out to be a bad antenna. They replaced the whole phone under the “battery replacement” plan so it only cost $50 or something and after that she had no issues.

Back then battery life was so poor I don’t remember that being an issue, but she was getting dropped calls and weak signal. But just like with you and your wife’s phone, my phone would have more bars than my mom’s even when we were in the same place. A hardware issue could explain why yours is not connecting and your wife’s has no trouble. Antennas do seem like something that could detach inside the phone and not give you full coverage, but still work in many situations.

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Maybe the 15 has a higher-gain radio. This would give you better coverage, but at the expense of more power drain when there is weak/no signal.

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You should be able to turn off 5G. I know I did that on my 13 Pro. Settings / Cellular; see this to force to LTE rather than 5G. Maybe that will help?

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Doh! Yes, Settings > Cellular > Cellular Data Options > Voice & Data > LTE will force LTE.

I dimly think I may have tried that back in December, but the fact that I didn’t remember the setting suggests that perhaps not. I’ve turned it on now and we’ll see if it makes a difference tomorrow.

Yeah, that’s one of those things that’s easier said than done when the nearest Apple Store is over an hour away. :-) But in fact, I may need to have some appointments near Syracuse, which will give me an excuse to go to the Apple Store and try the Vision Pro and get the iPhone checked out, assuming they can do it while I wait.

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Possibly related is an issue I had a couple of months ago. I exhausted my data allowance for the first time ever / in a very long while. For the next couple of weeks, until the allowance reset for the next month, I found my battery life was very markedly shortened.

Or possibly not related. Who knows?

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To me, and I am not an expert here, is that No Cell Coverage means that the phone does not think it has cellular signal. It suggests to me that since you can’t have no signal where you live (wife’s iPhone is fine), then I would expect some hardware issues. I found once that my fancy case actually blocked a lot of my cellular signal and its removal solved a host of issues. It could be that you have a bad antenna connection. It could be something else. If you can stand it, run it not in airplane mode but turn off the cellular connection in the control center and use only wifi for a day and see what happens.

BTW, I wouldn’t take the slow speeds at he eclipse as meaning anything. The cell tower was probably being pounded.

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Assuming Silicon Valley has very good cell phone coverage I am guessing that Apple engineers do not regularly get to test battery drain in poor signal areas. They probably have test facilities to simulate this (and there may not be a shortage of engineers who volunteer to take new hardware backcountry for testing :sunglasses:).

Antenna design is a challenging task so, speculating, it is not surprising that there is a large difference in battery performance between iPhone models in poor reception areas.

It would help if there was a setting to automatically turn off 5g if the signal was poor and LTE was available.

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Old story, but then sure did at one point. I assume it’s only improved.

At least on Verizon they do. The setting choice is 5G On (stay on 5G when it’s available, even if it reduces battery life), 5G Auto (turn on 5G only when needed while optimizing battery life) and LTE.

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The No Cell Coverage reading on iPhone 15 Pro stands at 17% for the last 10 days and 26% for the previous 24 hours. My provider is T-Mobile. A fire station is behind the building, and their radios may create extra noise and interference. The service typically shows 1 bar LTE in the home when I turn Wi-Fi off. With Wi-Fi on, it shows that I am using Wi-Fi calling.

Outside, things run a bit crazy. Around the building, I see LTE, 5G, and 5Gug, but with only 2 bars. Generally, away from my building, I see 5G service.

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Is “No Cell Coverage” actually an app that uses resources, or just a warning? I suspect it’s the latter.

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It’s iOS showing you something about what it’s doing, not an app in its own right.

Interesting—that’s pretty close to my readings. But I doubt I have any radio interference here at home beyond the usual residential Wi-Fi and fridge motors.

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For another data point: I don’t recall ever seeing “No Cell Coverage” in the Battery Usage by App list, and it currently does not appear on the “Last 10 Days” list. I have an iPhone 13 Pro Max running iOS 17.4.1. I will also add it is entirely possible I have been within range of cellular coverage continuously for the last 10 days.

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Here’s another data point. My no cell coverage is a lot lower than yours (~10%), to my big surprise. I work in a location where cell reception (all of it, not just “5G”) is spotty at best. This is on T-mobile. Verizon is better, but not by a whole lot. But then I’m in and out of heavily radiation shielded bunkers (think several feet of fortified concrete [sprinkled with baryte] plus lead and poly) all the time. When I’m in there, there is zero reception on any network.

Back in the day my iPhone would get on cell over wifi a lot since we have very good wifi coverage almost everywhere indoors, especially in those radiation areas. However, during the past year or so I’ve noticed that often my iPhone 15 will not get onto cellular over wifi even though the wifi network is there and reception is strong with easily ~80 Mbps transfers clocked. I don’t know if this has to do with our network and/or cyber security people (rumor has it they’re not the greatest fans of cell over wifi) interfering or just that the wireless network itself shows at times too much latency and so it doesn’t get picked for cellular traffic.

But bottom line, I get a lot of missed calls going to voicemail because I’m out of cell reception and my iPhone 15 spends a lot of time with poor signal trying to reconnect to a cellular networks. But the toll it has on my battery seems substantially lower than what you report. I’d second @xdev’s suggestion to have Apple run some diagnostics on it and make sure that everything with your antenna and cell radio checks out.

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If only Apple’s remote diagnostics could do this, but no…

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Sometimes my iPhone 15 Pro consumes a fair bit of power while not being active, and I suspected that it might be trying to maintain connection with the cell network while the signal is poor. My house does not have good cell coverage indoors, and it is almost non-existent inside my office. (I do not have an active 5G service.)

The typical power drain of my iPhone looks like this (note the rather steep slope of the curve):

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Thanks to this discussion, I finally got to work on a shortcut I meant to try for a while: Turn on Airplane Mode when connected to home or office WiFi, and turn off Airplane mode when disconnected from these networks. The resulting improvement in power consumption is much more satisfactory (the mostly flat line of the curve towards the right):

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So far, the only downside to this setup is that the Apple Watch will also switch to Airplane Mode and no longer able to unlock the Mac. Also, I cannot receive SMS via the cell network. I have not found the latter problematic since I rarely receive text messages nowadays (except through iMessages and other apps).