How to get real time battery level on iOS with a 1% granularity

Question

I'm using this function to get current battery level of device:

[[UIDevice currentDevice] setBatteryMonitoringEnabled:YES];
UIDevice *myDevice = [UIDevice currentDevice];

[myDevice setBatteryMonitoringEnabled:YES];
double batLeft = (float)[myDevice batteryLevel]; 
NSLog(@"%f",batLeft);

but the result has a 5% granularity. Example: when the phone battery is at 88%, it only logs a value of 0.85. batteryLevel only returns values in increments of 0.05. For example: 0.85, 0.9, 0.95 and never returns values like 0.82 or 0.83.

Is there any solution to get a percentage with a higher precision?

For the record: I just check your code with the iPhone 6 Plus and it does show all scalar levels, like 0.49 etc — brainray, Aug 09 '15 at 20:17

score 33 · Answer 1 · answered May 22 '13 at 15:04

33

There are at least four different ways to read the battery level, and all four ways may return different values.

Here is a chart of these values through time.

The values were recorded with this iOS project: https://github.com/nst/BatteryChart

Please check out the code for reference.

iPhone 5 Battery

answered May 22 '13 at 15:04

nst

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Does this app remain running and reporting percentages in the background? Or do you simply leave the app running? – simonthumper Nov 25 '16 at 09:17

score 10 · Accepted Answer · answered Aug 04 '12 at 09:17

10

check out this site : Reading the battery level programmatically

but, carefully use. all of the APIs used here are undocumented on the iPhone, and will probably lead to a rejection if you submit this application to the App Store. Although battery charge status is not exactly, I'd recommend using the UIDevice battery monitoring methods.

answered Aug 04 '12 at 09:17

bitmapdata.com

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Thank you for your link. I've checked out it. I saw this line: "Don't forget to remove the headers and libIOKit.A.dylib from your code before shipping!", did it mean after done, I can remove libIOKit.A.dylib and remove the headers from my code to upload to Apple Store? – cat Aug 06 '12 at 01:51

score 4 · Answer 3 · edited Nov 29 '18 at 00:24

4

UIDevice *myDevice = [UIDevice currentDevice];    
[myDevice setBatteryMonitoringEnabled:YES];

double batLeft = (float)[myDevice batteryLevel] * 100;
NSLog(@"%.f", batLeft);    

NSString * levelLabel = [NSString stringWithFormat:@"%.f%%", batLeft];    
lblLevel.text = levelLabel;

edited Nov 29 '18 at 00:24

PaulMest

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answered Aug 22 '12 at 12:55

user1617027

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Your first line is superfluous since you do exactly the same thing on the third line of code. – Victor Engel May 24 '17 at 19:56
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@VictorEngel I just edited it to remove the duplicate line of code. Thanks for pointing that out. – PaulMest Nov 29 '18 at 00:24

score 3 · Answer 4 · answered Feb 21 '19 at 14:28

3

Swift version to get the battery level:

UIDevice.current.isBatteryMonitoringEnabled = true
let batteryLevel = UIDevice.current.batteryLevel

batteryLevel return 0,39; 0,40 values for me.

answered Feb 21 '19 at 14:28

maxwell

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It is not working for me? Do I need to perform any other configuration? I am getting -1 as an answer. – Maninder Singh May 30 '19 at 14:02
Did you write this code? UIDevice.current.isBatteryMonitoringEnabled = true If you didn't write this you will get -1. – maxwell May 30 '19 at 15:06
Yes, I wrote this line "UIDevice.current.isBatteryMonitoringEnabled = true". Also, I am new to developing iOS Apps. I am calling this code form viewDIdLoad() method under ViewController. Also, I am connected to a simulator, not an actual phone. Will that make a difference? – Maninder Singh May 30 '19 at 15:13
1

Of course, the simulator will return "-1". Use this code only for real devices. – maxwell May 31 '19 at 07:51

score 2 · Answer 5 · answered Jan 20 '14 at 05:51

The answers above are very good, but they are all in Obj-C, I have used these with other examples to do the same task on MonoTouch, so I am putting my code here in case anybody needs it:

try
{
    UIDevice.CurrentDevice.BatteryMonitoringEnabled = true;
    _Battery.Level = (int)(UIDevice.CurrentDevice.BatteryLevel * IOSBatteryLevelScalingFactor);
    _Battery.State = UIDevice.CurrentDevice.BatteryState;
}
catch (Exception e)
{
    ExceptionHandler.HandleException(e, "BatteryState.Update");
    throw new BatteryUpdateException();
}
finally
{
    UIDevice.CurrentDevice.BatteryMonitoringEnabled = false;
}

I also have a full post on my blog to give all the details in here

score 1 · Answer 6 · answered Apr 21 '20 at 04:46

1

You can find a perfect answer here

Xcode: 11.4 Swift: 5.2

Click Here

answered Apr 21 '20 at 04:46

Sivabalaa Jothibose

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score 0 · Answer 7 · answered Mar 05 '20 at 06:40

If you are using swift 5.1 or greater this code will definitely work for you.

Step 1:- To get started, first enable the isBatteryMonitoringEnabled property of the current device, like this:-

UIDevice.current.isBatteryMonitoringEnabled = true

Step 2:- You can now read the current battery level

let level = UIDevice.current.batteryLevel
print(level)

How to get real time battery level on iOS with a 1% granularity

7 Answers7

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