How to use non-activated iPhone for daughter

[ddublu]

She uses it wifi only but because it's constantly "searching" it's killing the battery. I've got cellular turned off. What else can I do to allow it to be used as a wifi-only with minimal battery impact? iPhone 4S. Thanks.

 

[wordoflife]

Enable airplane mode, and then turn on Wifi.

Alternatively, remove the SIM card (might not make a difference on Sprint and Verizon models though)

 

[ugcop]

For clarification:
When you turned off cellular it only turns off cellular data. To turn off cellular voice which it is still searching for follow the previously posted instructions. That actually turns off the cellular radio.