iPhone 5 Rapid Battery Drain - No Standby

Hi folks - I have a 64GB iPhone 5. When wifi is enabled and I am at work (this doesn't occur on any other wifi network that I have yet found) the phone will not go into standby mode (though the screen turns off) as evidenced by the Usage and Standby times being almost identical. In approximately 3 hours, when wifi is enabled, my phone will go from 100% to below 20% and is quite hot to the touch. The wifi network at my work is WPA2 encrypted, wireless N and G, and 2 SSID's are broadcast for the same network (to support staff whose wireless laptops haven't been switched to the new SSID - don't get me started - it's a stupid setup). Anyways, the wifi quality is dodgy at past and even though the signal remains strong, internet connectivity frequently drops. I suspect that the wireless router is defective but I have no control over that and have been ignored by the IT folks. 🙂

To make matters even more interesting, my iPad 4 connects to the same network at work and the battery doesn't drain and the device goes into standby without issue.

If I disable wifi on the phone while at work, the phone goes into standby and the Usage actually reflects the amount of time the device is actually used (a fraction of the total time).

I have reset network settings on the phone, reflashed 6.01 and restored from backup, disabled location services, etc... but to no avail.

Do you think there is a defect with the phone in its ability to handle the dodgy wifi at my work when the iPad manages it fine or is there something else that I could do to stay connected to the wifi without the phone chewing through battery, heating up, and not sleeping?

Thanks folks!