iPhone 6s battery drains quickly with PM SIM. Another PM SIM in an iPhone 8 battery is fine

[ndy008]

Hi.

I have iPhone 6s with PM SIM and the battery drains quickly. I have another PM SIM in an iPhone 8 and battery last as expected.

Previously, This iPhone 6s didn't have any SIM and wifi only. No Battery issues.

I made sure no apps are running, reset the iPhone 6s a couple of times and removed case.

Fully charged phone at night and battery is down to 30% in the morning. Battery settings graph is steep downhill.

The battery settings activity has full bars but no apps under "battery usage by app"

I assume backend process used up the battery, but I cannot tell what and why.

Signal coverage is ok where I am and I have another PM SIM on iPhone 8 that have no problem.

I will try Apple support, but I am worried that Apple may blame on PM SIM.

Welcome any suggestions.

Thank you.

[claudelamoureux]

One test you can do is during the night, put the phone in airplane mode, no cell coverage, no bluetooth, no wifi. Over a normal 8 hours night, the battery should not change (if you don't use it) if it drain, it could be the power converter in the phone that is defective (if they tell you that the battery is ok)

[liuxinbing]

I think that the 6s is too old and we need to move on to a newer version. My daughter uses 6s too and gets similar issue. I am going to let use my wife's iphone 8 and buy my wife an XR.

[luke11992]

The only difference I can think of is that now there may be data enabled and the scanning for cellular networks is causing a greater battery drain.

[ndy008]

I finally switched iPhones with my kids. The power draining problem did followed the iPhone 6s.

Although Apple Genius bar tech told me iPhone 6s battery is good (92% peak health) and no other issues found, I think something is not right with the iPhone 6s.

I will try Genius bar one more time to confirm the issue.

Thanks everyone for the wonderful support and patients.

[Korth · Accepted solution]

The SIM card itself imposes an utterly trivial drain on power, and it can't run any software on the device, and it can't control any hardware on the device. Some SIM cards are equipped with extra NVRAM storage, a SIM-IO interface (for firmcode dev),  an active cryptocircuit (for TPM), and/or a semi-passive RFID transponder (for SIM-secured NFC) - these features are limited to a combined power consumption of <0. 5W (which is insignificant) - and they're never found on Public Mobile SIM cards anyhow.

But the presence of an active SIM can signal the device operating system to turn on cellular radio, etc, and constant radio activity has harder draw on an already-old already-failing battery. Especially in fringe-service areas (with low signal bars) because more signal traffic (for stuff like pings, handovers, and error correction). And even worse when Data is involved as the phone hardware multiplexes packets across multiple bands.

Technobabble aside, you'll notice an old battery runs hot and runs down very quickly. 

You might be able to gain more oomph by disabling background data, etc, but if your battery is dying then no amount of software settings will avert the inevitable. 

You can run software (like iCopyBot) to view advanced battery stats like Total Charge Cycles. (And for reference, Apple rates their batteries for 2 years of "average use", consistent with about 400 Charge Cycles, after which they've been de-rated to <80% their new-rated capacities and pretty much force the device to constantly run on "Low-Power Mode"). 

You can buy a new battery (along with the tools needed for battery replacement) from iFixit. 

[ndy008]

@GinYVR, I am considering it. My daughter won't like it but, I may have to.

[GinYVR]

@ndy008Have you thought of just starting a fresh? Make sure you have a back up first.. verify your contacts etc are on iClouds. Erase your phone, when setup choose Start a new iPhone selection (instead of restore from backup).. try that for a day or 2 to see if there are any issues.

[ndy008]

*Issue not have been resolved.

Some update since visit to Apple Genius bar.

Apple tech confirmed battery is fine. He sees unknown background activities and the activity is not from an user application.  He said he cannot tell which backend system activity is running constantly.

He told me to reset all setting, which does not impact apps and user data. - Did not help.

And then he told me to try restore from iTune backup. - Did not help.

Next step.

I am going swap two PM SIM cards between my iPhone 8 and my kid's iPhone 6s to check if the background activity follows the SIM card or the phone.

I am worried that some kind if carrier update is in a loop even though carrier version seems upto date.

I will post update soon.

[CalgaryBen]

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@ndy008 wrote:

The battery is at 92% capacity. I replaced the battery when Apple replace it for $30 last year.

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The 8% drop in a year seems a bit steep for a short period of time... but of course this could be a combination of things (both usage as well as charge habits/cycles).  I definitely couldn't imagine any correlation between a PM SIM and the rate of depletion, and would chalk that upto coincidence.  I'd be more concerned about what apps accelerate drain under General --> Battery.

Apple says the iPhone battery is "designed to retain up to 80 percent of its original capacity at 500 complete charge cycles".  Those numbers seem conservative (i.e. I would expect more like 800-1000 cycles before dropping to 80%), but I also feel/see a noticeable difference in usability by the time it reaches ~90-94%.  At that point, I personally feel inclined to swap the battery (even at the current $65+tax, I think it's a decent price compared to a new phone).  I'd definitely have a genuine and new Apple battery installed.

[taylorharrison]

I just switched my sons iphone 6s over to pm, he had a battery drain issue prior to the move his battery got worse this week, so my wife took it into the apple store, where they switched out the battery for a new one. works great now.

It was never a question of your or any simm card, it's the battery on the 6S that's the issue.

you just need to replace it.

[srlawren]

@CalgaryBen , do you have any suggestions here?  

[ndy008]

@hairbag1Interesting. I recall having charging issue with my old old Samsung flip phone. Shows as fully charged, but was not. Olny found out after I replaced charger.

I will try charging the iPhone 6s using Apple charger and cable.

[ndy008]

@GinYVRThanks for the reply.

The battery is at 92% capacity. I replaced the battery when Apple replace it for $30 last year.

[hairbag1]

Check to make sure the charging cable is in good shape too. I had one fail with similar symptoms as you...soon as I got the new charging cable, the battery was happy.

Might not be the same issue, but give it a try before investing in new battery.

[GinYVR]

@ndy008The 6s is nearly 4 years old, if you haven't replace the battery yet you should. You should able to see the battery health under the Settings -> Battery section.

If the phone turns off without warning you about low battery, the battery needs to be replaced.

[Triguy]

Make sure you turn off wi-fi and gps (location).