iPhone 4S (iOS6.1.3) battery draining at night

[Eis]

Hi

I know there have been a lot of complaints about iphone batteries but mine has been fine for about 1.5 years but this week has suddenly started draining overnight, despite being almost fully charged when going to bed (so it is draining in about 7 hours, if not quicker, despite not being used). I don't think I am doing anything different. I have the alarm set which obviously doesn't go off because the battery has drained.

Any suggestions? Thanks!

 

[MrMacMack]

Backup up to icloud and then erase all content and settings. From there, setup as new and compare. If the battery still drains then it's not a software issue. After you're done testing, erase all content and settings and setup using your icloud backup to put everything back prior to the test.

 

[xizdun]

It could be an app running in the background that's to blame. Try killing background apps, or simply restart your iPhone. Make it a habit of killing apps from the background that potentially run in the background after you're done using them.