12 Replies Latest reply: May 28, 2012 10:08 AM by GZukes
Roberticus1234 Level 1 Level 1 (0 points)
If you leave wifi on and you put your ipad to sleep, does wifi power down -- or does it continue to drain battery?

In other words, am I correct in assuming that if I want to cut down on battery use, I should turn wifi off every time I put the pad to sleep?

(I've got the iPad 3G, but use it in airplane mode with wifi turned on... Unless I put it to sleep in which case I turn wifi off... Am I doing all of this unnecessarily?)

Macbook Air, Mac OS X (10.5.2), 1.6
  • Tamara Level 6 Level 6 (13,730 points)
    Wifi sleeps until you wake the device up.
  • Craig Brady Level 4 Level 4 (1,790 points)
    If you have Push Services enabled for email and applications, the WiFi does not go completely to sleep.
  • Roberticus1234 Level 1 Level 1 (0 points)
    Tamara,

    Thanks for this -- but how do you know that it sleeps?
  • Tamara Level 6 Level 6 (13,730 points)
    That's the way Apple designs wifi to work. If I sleep my Macbook or any other Apple device, wifi sleeps until I wake the device.
  • Doug Eldred Level 4 Level 4 (3,270 points)
    This seems to be different between my iPod touch and my iPad. Both are set up for push notifications from MobileMe. Generally, the iPad sees the overnight mail, and my iPod touch generally doesn't, when first "turned on" in the morning. Once in a while, the iPod touch does too, but I've never figured out what the scenario for that is. You can of course power the iPad down, or disable Wi-Fi, but unless you really REALLY don't want overnight push notifications (and losing a little battery charge) you don't have to do so.
  • Pappasbike Level 3 Level 3 (560 points)
    I have the 3G ipad but only use wifi, haven't activated a data plan. I notice that my ipad handles wifi unlike any of my other devices. They, imac, MB Pro ipod touch, iphone, drop their wifi when in sleep but the ipad never drops it. I check this by going into Airport utility on my mac, I use an Airport Extreme base station that all my devices connect to by wifi. Airport Utility has an Advanced section that shows all wireless devices connected to the network and their signal strength, noise and transmission rate. My ipad is always showing as connected, asleep or not. The other devices will drop out of the displayed graph when they go into sleep but not the ipad. So however wifi is implemented on the ipad it's very different from all the other devices. This may be one reason why I've never had the issue of the ipad losing its wifi when coming out of sleep. Actually the only wifi problem I've ever had is that every now and then the wifi antenna symbol will completely disappear triggering an alert that says connecting for a few seconds when the antenna reappears and the connection is made again. Weird but it happens very infrequently.
  • LamyStacy Level 1 Level 1 (0 points)

    I have found that in certain circumstances my Wifi disconnects totally when my IPad keeps. I must go through all the steps to get it to locate the wifi again. Even with my home router that I have password set up in my IPad. Trying to find an answer to fix this. Hope I used the correct terminology

  • GZukes Level 4 Level 4 (1,565 points)

    The WiFi does turn off when the iPad is placed in sleep mode, unless it is connected to a power source.  To answer your question to Tamara, I have done ping tests to verify this behavior.  When in sleep mode and not connected to power I get no response to pings.  When connected to a power source, I get a response from my iPad to the pings.

     

    I just performed a test on Craig's Info on Push Services.  Email does come through when the iPad is in sleep mode but takes a long time to come through.  I suspect that when your iPad is in sleep mode email falls back to the Fetch schedule.

  • pjl123 Level 5 Level 5 (6,160 points)

    Gzukes, I am not sure it needs to be connected to a power source.  I get notifications all the time when my pad is asleep, and not plugged in.

  • Paul Skee Level 2 Level 2 (210 points)

    My iPad2 (wifi only) has been asleep, disconnected from power for several hours. I used my iPhone to locate the iPad w/"find iPhone". It successfully located the iPad within 10 seconds. this sugests that wifi is indeed active during sleep.

  • GZukes Level 4 Level 4 (1,565 points)

    I never said that you couldn't receive notifications or email when not plugged in.  In fact I agree with Craig Brady that WiFi probably doesn't go to sleep completely.  My tests indicate that at least for emails, WiFi does wakeup and periodically check for Pushed emails.  I further suspect that the frequency it checks for Pushed emails may be tied to the Fetch frequency in Settings.  I plan to set it to Manual tonight and see if I get any emails overnight with the power off.

  • GZukes Level 4 Level 4 (1,565 points)

    Forget what I said about the Fetch settings.  Mea Culpa.  I sent emails to a Fetched account.  That is why it was using the Fetch schedule.  I performed more tests and found that Craig is absolutely correct.  I sent an email to a Pushed account while running countinuos pings to the iPad that was in sleep mode and not connected to power.  Before the email was sent I was getting no ping responses.  Just after I sent the email, the iPad began responding to the pings and the email was received.  After receiving the email, the iPad quit responding to the pings.

     

    My conclusion is that for the most part, WiFi goes to sleep when the iPad is in sleep mode while not connected to a power source.  There is a part of the WiFi that watches for Pushes and wakes the main portion of WiFi to receive any Pushed data.  In addition the WiFi comes awake according to the Fetch schedule to get those emails.