It seems that stopUpdatingLocation
is what triggers the background watchdog timer, so I replaced it in didUpdateLocation
with:
[self.locationManager setDesiredAccuracy:kCLLocationAccuracyThreeKilometers];
[self.locationManager setDistanceFilter:99999];
which appears to effectively power down the GPS. The selector for the background NSTimer
then becomes:
- (void) changeAccuracy {
[self.locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
[self.locationManager setDistanceFilter:kCLDistanceFilterNone];
}
All I’m doing is periodically toggling the accuracy to get a high-accuracy coordinate every few minutes and because the locationManager
hasn’t been stopped, backgroundTimeRemaining
stays at its maximum value. This reduced battery consumption from ~10% per hour (with constant kCLLocationAccuracyBest
in the background) to ~2% per hour on my device.