Question

Does anyone know how (if possible) I can find out how much capacity (mAh) is remaining in an iPhone battery at any given time?

Something like the program above?

Is there a value stored in a plist somewhere??

Answer 1

couple ways,

• pre 3.0 sdk: http://blog.coriolis.ch/reading-the-battery-level-programmatically/

• with 3.0 sdk – the UIDevice batteryLevel property (example: http://blog.coriolis.ch/reading-the-battery-level-programmatically/#comment-4607)

to gauge the mAh you could check the battery level over time using that method.

3.0 has added an event to do that:

[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(batteryChanged:)
name:@”UIDeviceBatteryLevelDidChangeNotification” object:device];

in general, measuring the open circuit voltage or current is used to gauge the state of charge by the hardware. the capacity of the bat will shrink over time, so 100% will indicate no more charge can be stored, even tho the capacity is lower than a new iphone battery.