The claim has been repeatedly made on the internet (example: 1, 2, 3* )that when a mobile phone is connected to WiFi, disabling cellular data can extend battery life, as it stops the phone from looking for 3G signals. Equally, there are several counterclaims to this idea (example), which basically claim that when on WiFi, many phones automatically turn off their 3G radios, making this pointless.

Is there evidence to support this, for some or all models of smartphone (or for some or all types of popular smartphone software)?

*Yes this is an SE answer, but no sources are cited, so I'm treating it as a claim

  • 2
    There are two claims: (1) At least one model of phone turns off the 3G automatically. That could be be answered positively with a quote from a manual, but is unfalsifiable. (2) That turning off Cell Data extends the life of the phone. That could pretty much only be answered by a huge experiment, that I doubt anyone has done - but I could be wrong.
    – Oddthinking
    Jul 19, 2015 at 4:06
  • For a start, one could compare transmission power and transmission patterns of WiFi / G3 to check if the claim is plausible?
    – Suma
    Jul 19, 2015 at 18:47
  • @Oddthinking - #2, not necessarily. There are apps that trace the souce of battery drain on Android. Presumably, if it's granular enough to include specific hardware pieces, a big experiment isn't needed.
    – user5341
    Jul 19, 2015 at 23:40
  • @user5341: The app would need to be run on dozens of models of phones to show the results are widely applicable, and several times to show the results hold independently of the amount of data transferred, strength of 4G signal, etc.
    – Oddthinking
    Jul 20, 2015 at 2:16
  • 3
    This sounds very much like a question that can't be answered beyond "It might, but it would depend on the phone, so ask your salesman before buying"... Jul 20, 2015 at 11:23


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