What are Push Notifications under System Services?

Gator5000e wrote:

Lawrence, thanks. You dropped in the other thread called iOS 8.1.3 - Battery Draining Very Quickly. I don't really think it's anything you listed. I restored my phone and set it up as a new phone on Saturday. the 13MB of Push Notification data is just from late Saturday afternoon when the set up finally finished. So for Push Notifications for phone, messaging and calender to rack up that kind of data is not right.

Actually, that probably is right. If you set it up as new it had to sync your entire calendar history to the phone. I don't know how large your calendar history is, but mine is every event for the past 15 years. If you reset it now and it still accumulates data quickly then there might be a problem. But when you set up as new everything must resync.

There is something going on under the hood of 8.1.3. The Push Notification numbers are listed in the cellular section of system services. Since Saturday, i have been on WiFi 90% of the time, either at home or at work. Why would there be cellular data used for Push Notifications when I'm on WiFi?

Possibly because you are not on WiFi when the phone goes to sleep, unless it is connected to power. iOS turns WiFi off when the phone goes to sleep to preserve battery life. WiFi (as required by the standard) uses power continuously when connected, whether you are transferring data or not. Also, Notifications do not go over WiFi; they go over the cellular channel, because that's the only way an external trigger can wake the phone. Once an app has received a notification if it needs to do a data transfer it can use WiFi (if it is on), but the notification itself is always over the cellular channel.

Push notifications are the mechanism by which an external server can wake up the iPhone. For the ones you mention:

• Phone - alerts you when you receive a visual voicemail
• Messages - whenever you receive an iMessage or FaceTime contact
• Calendar - whenever a calendar entry is updated or added from another device, and also to alert you when a calendar item's "notification" alert occurs

The data total for any item is all of the data since the last time you reset statistics. So if you never reset statistics that 13 MB is the total since you got the phone. It's useful to reset statistics at the beginning of each billing cycle, so you can track what has used data for your current billing cycle.

Notifications are rarely a cause of battery drain. Most battery drain comes from apps. Either apps you are using actively, apps that stream content such as Pandora when the phone is asleep, or apps that are running in background. Sometimes an app gets "stuck" in a loop attempting to send data and failing, but it keeps trying. This most commonly happens after you have updated iOS because the app got suspended by the update process and lost its connection as a result of the update. But when it is unsuspended it doesn't check for this condition and just keeps trying on the now "stale" connection.

To check which apps or services are draining your battery the most use the Settings app.

Settings > General > Usage > Battery Usage

Wait a few seconds and your iPhone will display a list of apps using the battery. They will be listed from the most to least and show how much of the battery drain the app is causing. With that knowledge you can take steps to reduce battery usage.