WiFi impact on phone battery

I thought I’d start this thread here so as not to drag the iOS 11 Betas thread further off topic. :open_mouth:

I’m not sure how much searching the WiFi does, if you’ve turned off the option to notify you of new networks. I think in that case, it only scans for networks if it needs assistance in determining your location. In any case, whilst I agree that some scanning will go on in the background, what I’d really like to know is what impact this has on the battery.

I would hope that with the integrated electronics and software in the iPhone, this would be negligible. Moreover, I’d prefer engineering effort was spent on reducing WiFi power to negligible levels when I’m not connected to a WiFi network. Turning WiFi on and off it too much of a hassle for me. I like to just leave things on and have the phone manage the power.

Anyway, if anyone has any figures on background WiFi power draw, I’d definitely be interested!

I have a real problem with battery life on my Samsung when WiFi and mobile data left switched on. The power saving option specifically states that it switches of background WiFi to save battery. On other OS unsupported by Monzo I have phone settings that alter the frequency with which the phone actively seeks a WiFi signal. On my Android there is also additional settings regarding WiFi use while in sleep mode so it is clearly a power issue

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I agree about turning off wifi being too much of a hassle.

It will use some power though because it will be searching for networks it knows in the background. Also, if you are paranoid about privacy, you should be aware that when it searches it actually says ‘is WIFI SSID previously used SSID available?’ - this leaks the SSIDs of all of the networks you’ve used recently, although I’m not sure how far back in the list it goes.

There were stories that there are WiFi points dotted around listening out for phones requesting access - it is possible to track you in this way. Also, Apple, and I assume others, have maps of WiFi SSIDs so they can use the SSID you are connected to to help locate you.


It will be doing a whole lot of searching for WiFi points, otherwise how can it automatically connect you to ones you’ve saved the details of? I’m an Android user but my phone will usually connect to a saved WiFi point within about 20 seconds of coming into range and the searching itself seems to take about half that time so it must be scanning every 10 seconds or so!

I don’t find this uses up much of my battery though… in fact having WiFi off can lead to more battery usage and you might miss opportunities to connect to WiFi and instead end up using much more 4G.

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One important point to take note of, turning off WiFi means that location services will cause GPS to be active more often as WiFi beacon frames are used for lower power, more accurate (especially indoors) location.

In reality, leaving WiFi on isn’t such a huge power draw nowadays. Modern radio chipsets in iOS and Android devices are perfectly okay with not being connected to a network and just listening for the advertising beacon frames of known networks or using them for positioning.


I leave my wifi on most if the time however if I need to save battery on the iPhone then I turn on Low Power setting, turn off wifi, turn off 4G and turn off location settings (this is the killer).

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I leave WiFi on most of the time since I track my location (uses surrounding WiFi to track location) using the Life Cycle app, it’s pretty handy esp when travelling and detects movement/sleep too. Most of the battery drain goes to Google maps/Citymapper when I’m out and about so I usually bring a portable charger. I don’t think I’d turn WiFi on/off for this reason, the battery drain in comparison is negligible. I only wish iPhones put the option to turn data on/off in control centre, like android does. Would save me so much hassle

It does on iOS 11


Finally, I’ve been griping about this for ages! Can’t wait for it to be rolled out now

It’s not bad although that have taken away the slide left n right in control centre and now you have to hold down the HomeKit icon to get to scenes.

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I wish there were more customisation options, whenever there is a new update I sort of gripe about it for awhile and eventually just deal with it. Removing swipe to unlock threw me off for a good few weeks. I think one of the things I miss about android was the ability to set home screens to a specific screen + have widgets on the screen itself. It’s only a click/swipe more but I liked having specific Google keep lists on the screen

That’s the main reason why my iPhone is consigned to a drawer and I use Android as my main phone

I think mobile data is a lot more to blame there than WiFi is.

In general mobile data consumes a lot more relative power than WiFi, with the power consumption for both increasing with a lower signal strength.

Quite a lot. WiFi devices are constantly sending out “probes” to connect to known networks. However, (especially newer devices) they’re quite optimised and the power consumption should be minimal.

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Definitely. Location and mobile data are the big killers there.