Got this from the developer forums, and it has worked for me. Battery is almost as good as it was for me in 8.4. Not quite the same, but that should be expected given the new features and beta 1.
Credit to user Atomic Flip in the developer forums who posted the following:
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"1. Completely disable iCloud Backups on each device running iOS 9 Beta 1 (Use iTunes to Backup and restore devices for now.)
2. Disable iClkoud drive (if you enabled it) on each device running Beta 1
There appears to be a SERIOUS problem with the API handling backups to iCloud or some sort of permissions issue with the data being written to iCloud. This likely went into effect during the update phase that indicated "iCloud data is being updated". (During the first Beta 1 load.)
This has confirmed to entirely resolve the "somewhat unpredictable" and extremely high rate of burn on the battery for this beta on iPhone 6, iPhone 6 Plus and iPadf Air 2. There is no reason to believe other affected devices will respond any differently to these changes, so we encourage other developers to try them asap. Apple should likely address this with the next update, when we can resume use of iCloud as normal during testing.
NOTE: iCloud data used by Third Party applications and other data like Calendar, Contacts and so on, does not appear to be causing any issues with battery usage, nor does there appear to be any data corruption. However do proceed with caution if you are using iCloud for your beta application development."
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As I said, this has worked wonders for me. Hopefully it will help some here as well.
Credit to user Atomic Flip in the developer forums who posted the following:
----------
"1. Completely disable iCloud Backups on each device running iOS 9 Beta 1 (Use iTunes to Backup and restore devices for now.)
2. Disable iClkoud drive (if you enabled it) on each device running Beta 1
There appears to be a SERIOUS problem with the API handling backups to iCloud or some sort of permissions issue with the data being written to iCloud. This likely went into effect during the update phase that indicated "iCloud data is being updated". (During the first Beta 1 load.)
This has confirmed to entirely resolve the "somewhat unpredictable" and extremely high rate of burn on the battery for this beta on iPhone 6, iPhone 6 Plus and iPadf Air 2. There is no reason to believe other affected devices will respond any differently to these changes, so we encourage other developers to try them asap. Apple should likely address this with the next update, when we can resume use of iCloud as normal during testing.
NOTE: iCloud data used by Third Party applications and other data like Calendar, Contacts and so on, does not appear to be causing any issues with battery usage, nor does there appear to be any data corruption. However do proceed with caution if you are using iCloud for your beta application development."
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As I said, this has worked wonders for me. Hopefully it will help some here as well.
