Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A334 Safari/7534.48.3)
Try going to settings> general> reset> reset all settings
Then only turn on battery percentage and test out the standby
Try going to settings> general> reset> reset all settings
Then only turn on battery percentage and test out the standby