battery level on iphone2 was much lower than on iphone1

[shankari]

While investigating the behavior of the iphones after reboot (https://github.com/e-mission/e-mission-server/issues/378#issuecomment-244172432), I noticed that of the two iPhones that I was testing one of them had much lower battery level than the other.

iPhone1: 74%
iPhone2: 16%

Checking the battery usage, it looked like emission was the main user.
I pulled the automatically logged battery data, and the battery level was almost identical until 5pm on the 31st when we left dance class.

iPhone 1

111     2016-08-31T16:00:08.950474-07:00    85.000000
116     2016-08-31T16:26:28.220186-07:00    83.000000
121     2016-08-31T17:00:05.247026-07:00    83.000000
125     2016-08-31T22:43:02.321156-07:00    81.000000
128     2016-08-31T22:45:29.233123-07:00    81.000000

iPhone 2

115     2016-08-31T16:00:13.057848-07:00    84.000000
119     2016-08-31T16:25:31.215741-07:00    83.000000
124     2016-08-31T17:00:04.391507-07:00    82.000000
128     2016-08-31T17:39:24.639105-07:00    81.000000
132     2016-09-01T11:53:11.614195-07:00    19.000000

[shankari]

Attached logs.
loggerDB.drain_mismatch.gz