'Enable LTE'. Does it drain battery while on wifi?

heyyitssusan

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Original poster
Feb 9, 2014
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Should I turn it off while on wifi or just leave it on? Does it matter at all?
 

rockitdog

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Mar 25, 2013
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No, it doesn't drain battery because when it's on wifi it's using the wifi signal and not searching for LTE.
 

nebo1ss

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Jun 2, 2010
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I find it works the other way around. When you are on Cell it is constantly trying to get a wifi signal and switch to wifi. This is not great for the battery life. I tend to turn wifi off when leaving the house.
 

Applejuiced

macrumors Westmere
Apr 16, 2008
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At the iPhone hacks section.
I find it works the other way around. When you are on Cell it is constantly trying to get a wifi signal and switch to wifi. This is not great for the battery life. I tend to turn wifi off when leaving the house.
It wont search for wifi or switch to wifi if you have "ask to join networks" turned off.
It will just auto connect to known wifi networks you connected before and not use any additional battery.
 

nebo1ss

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Jun 2, 2010
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It wont search for wifi or switch to wifi if you have "ask to join networks" turned off.
It will just auto connect to known wifi networks you connected before and not use any additional battery.
How is it going to auto connect to known wifi networks you connected to before unless it is constantly checking wifi network that are available? Seems a bit of a Conundrum.
 

ardchoille50

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Feb 6, 2014
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I use wifi at home on all of my iOS devices - I use my iPad 4 for desktop-type use. I keep a close eye on my LTE data usage and I haven't seen any major increases. So, as far as my use is concerned, no, using wifi doesn't cause any noticeable increase in LTE data usage. You can always enable airplane mode and then turn on wifi if you want to be sure.
 

MEJHarrison

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Feb 2, 2009
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It seems to me that even if you're on wi-fi, it's still going to be searching for an LTE signal. If nothing else, calls and texts stills need a valid cellular connection. So even on wi-fi, it's going to be looking for a good signal.

I suppose to some degree, that's going to be draining your battery. Of course there's only one way to determine if that drain is too big or not. And that would be for you to turn cellular off and see what kind of difference (if any) that you notice. Then make a decision based on the data you've collected for your own personal tastes.
 

nebo1ss

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Jun 2, 2010
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It seems to me that even if you're on wi-fi, it's still going to be searching for an LTE signal. If nothing else, calls and texts stills need a valid cellular connection. So even on wi-fi, it's going to be looking for a good signal.

I suppose to some degree, that's going to be draining your battery. Of course there's only one way to determine if that drain is too big or not. And that would be for you to turn cellular off and see what kind of difference (if any) that you notice. Then make a decision based on the data you've collected for your own personal tastes.
A little know limitation of how LTE is implemented today is that it does not carry voice. LTE is a packet switched network while voice is circuit switched. your phone still supports the old circuit switched capability ie GSM 3G and uses it to carry voice and SMS. If you are using voice and data simultaneously you will in fact be using the 3G network.

Hopefully this will change in the future.
 

maflynn

Moderator
Staff member
May 3, 2009
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Boston
I leave LTE on regardless if its on wifi, the only time I'll turn it off, if over night and even then if only the battery level is very low and I want enough battery to last my morning commute.
 

Zxxv

macrumors 68040
Nov 13, 2011
3,563
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UK
I leave LTE on regardless if its on wifi, the only time I'll turn it off, if over night and even then if only the battery level is very low and I want enough battery to last my morning commute.
Are you afraid to charge your iphone?
 

I7guy

macrumors Core
Nov 30, 2013
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Gotta be in it to win it
A little know limitation of how LTE is implemented today is that it does not carry voice. LTE is a packet switched network while voice is circuit switched. your phone still supports the old circuit switched capability ie GSM 3G and uses it to carry voice and SMS. If you are using voice and data simultaneously you will in fact be using the 3G network.

Hopefully this will change in the future.
Voice over lte is coming to verizon.
 

maflynn

Moderator
Staff member
May 3, 2009
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Boston
Are you afraid to charge your iphone?
Not at all, just that I don't have a charger handy by my bed, so I wait until I get into the office before plugging it in.

Generally speaking it lasts through the night without issues, but if I have about 30% when going to bed, I'll turn off LTE, that way I have plenty to get through my commute (listening to music, FB/emails/games)
 

I7guy

macrumors Core
Nov 30, 2013
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Gotta be in it to win it
Not at all, just that I don't have a charger handy by my bed, so I wait until I get into the office before plugging it in.

Generally speaking it lasts through the night without issues, but if I have about 30% when going to bed, I'll turn off LTE, that way I have plenty to get through my commute (listening to music, FB/emails/games)
At night I turn off lte and leave 3g on. For the 3 seconds it takes me, if it saves any battery it's worth it.
 

MEJHarrison

macrumors 65816
Feb 2, 2009
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A little know limitation of how LTE is implemented today is that it does not carry voice. LTE is a packet switched network while voice is circuit switched. your phone still supports the old circuit switched capability ie GSM 3G and uses it to carry voice and SMS. If you are using voice and data simultaneously you will in fact be using the 3G network.

Hopefully this will change in the future.
Fair enough. The point is, just because you're on wi-fi, does NOT mean your phone still isn't searching for cellular connection. A minor point to be sure. But after reading some of the comments in this thread, it seemed not everyone grasped that point.
 

wordoflife

macrumors 604
Jul 6, 2009
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Only if your LTE signal is considerably poorer than your 3G/4G signal. They use the same chip, but it has to work harder if there is poorer signal.
 

C DM

macrumors Sandy Bridge
Oct 17, 2011
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Fair enough. The point is, just because you're on wi-fi, does NOT mean your phone still isn't searching for cellular connection. A minor point to be sure. But after reading some of the comments in this thread, it seemed not everyone grasped that point.
But realistically it shouldn't be looking for LTE at that point and perhaps 3G at best if not less than that (basically what's needed for calls and messages as data is taken care of by WiFi).
 

Daveoc64

macrumors 601
Jan 16, 2008
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Bristol, UK
Fair enough. The point is, just because you're on wi-fi, does NOT mean your phone still isn't searching for cellular connection. A minor point to be sure. But after reading some of the comments in this thread, it seemed not everyone grasped that point.
This is very important. Even when you have an excellent Wi-Fi signal, you still need a 2G, 3G or 4G (where 4G = LTE in my book) signal for phone calls and SMS*.

Your phone will not stop using the cellular network for those things when you are using Wi-Fi and it won't magically switch to an earlier generation network (e.g. from 4G to 3G) to save power when you're using Wi-Fi.

Terms like 2G, 3G and 4G don't refer to data connections - they are merely talking about the mobile network itself.
 

C DM

macrumors Sandy Bridge
Oct 17, 2011
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This is very important. Even when you have an excellent Wi-Fi signal, you still need a 2G, 3G or 4G (where 4G = LTE in my book) signal for phone calls and SMS*.

Your phone will not stop using the cellular network for those things when you are using Wi-Fi and it won't magically switch to an earlier generation network (e.g. from 4G to 3G) to save power when you're using Wi-Fi.

Terms like 2G, 3G and 4G don't refer to data connections - they are merely talking about the mobile network itself.
Well, at least so far, LTE does in fact only refer to a data connection, unlike some of the other ones that can be used for calls/messaging.
 

Max(IT)

Suspended
Dec 8, 2009
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Italy
It wont search for wifi or switch to wifi if you have "ask to join networks" turned off.
It will just auto connect to known wifi networks you connected before and not use any additional battery.
If the wifi is on, it will search for networks, known or unknown, so it basically will drain the battery a little more.
 

C DM

macrumors Sandy Bridge
Oct 17, 2011
47,538
16,039
If the wifi is on, it will search for networks, known or unknown, so it basically will drain the battery a little more.
Although even if that's the case, for the vast majority, the battery usage from that is essentially negligible.
 

C DM

macrumors Sandy Bridge
Oct 17, 2011
47,538
16,039
Agree.
But I also think that LTE on has a little impact in battery life compared with 3G.
Yeah, more or less the same things should apply to both--mainly it's only when the signal is weak and the radio keeps on trying to connect to it or hold on to a weak signal (be it 3G or LTE or any signal really that the phone supports), that's when extra battery usage would come into play, otherwise any increase to the battery usage related to just getting and holding a decent/good signal should be fairly negligible for most.