GPS, Wifi, and Battery: The Truth


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  1. ejchis

    ejchis Well-Known Member This Topic's Starter

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    Okay, I've seen this issue come up a lot lately, and I'm curious. I'm curious because I only turn Wifi on when I'm at home, and I only turn my GPS on before I use an app the requires GPS. Turning these radios on and off is simple enough, but it is a little bit of an annoyance, especially GPS when I get that damn dialog every time I open Navigation.

    Here's what I want to know: Will leaving Wifi and GPS on all the time have any notable effect on my battery life? I don't have any problem with my battery life right now, so a slight effect won't be a huge deal. But I keep reading about Wifi sleeping when the screen is off and GPS being idle unless being called up by an application.

    I'd like to know the truth. Who has it?
     

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  2. Rigmaster

    Rigmaster Well-Known Member

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    That's not a simple question. Whether GPS is on or not isn't the concern - what's using GPS and how often it's calling upon GPS matters. That said, I don't have many apps that are GPS-users so it doesn't have much of an impact.

    The Wifi-GPS connection means little. It's the apps using GPS. When you surf, it might not be much until you start hitting pages that are full of geo-tagged info. That said, again since you're in a fixed location and depending on where that location is, geo-tagged info and items to be found via GPS proximity finders determine how intense your GPS use really is.

    Also, remember that GPS relies on both satellite and tower information so it does reach out for the towers if they're nearby.
     
  3. ejchis

    ejchis Well-Known Member This Topic's Starter

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    It's never as simple as you want it to be, is it?
     
  4. RiverOfIce

    RiverOfIce Banned

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    Wireless is pretty much the same. Depending on how you use it.

    When in idle mode and connected to the network, your wireless card uses almost no energy. With most wifi cards, you can set it to just search for your access point and nothing else, so when you leave that area, it is not mindlessly searching for access points. That is not how the evo works, oh no. If you leave the wifi area, the phone will still search for new access points, sucking battery along the way. The only way I know to stop it, is to turn it off. Which makes a little sense but not much.

    So bottom line, if you are with in normal connect with a number of set routers, wifi uses very little battery. But if you spend alot of time away from normal routers, then it sucks more then it should. So turning on and off your wifi will save you more battery depending on how you use it.

    The phone has to cycle the connection.
     
  5. 81_

    81_ Banned

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    test it
     
  6. Ze2o

    Ze2o Well-Known Member

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    The only reason why people say that turning off GPS, Wifi and etc to save battery life is because they're all constantly sending signals back and forth. Even if you're not connected to a wifi, your phone will constantly try to detect a signal.

    Not totally sure how much battery it actually uses to send signals back and forth tho.
     
  7. Brent Pierce

    Brent Pierce Well-Known Member

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    I leave GPS on 24/7. I NEVER turn it off. I do, however, turn wifi ON/OFF depending on where I am. I can last throughout the day depending on usage and whether or not I have certain apps installed/running.
     
  8. ejchis

    ejchis Well-Known Member This Topic's Starter

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    That makes sense about the Wifi. I'm usually not around an access point. My office would require special setup, but it's unnecessary because I'm sitting at a computer the majority of the day. And I'm really only home to sleep, at which time, I'm doing very little web surfing.

    GPS I guess is a bigger factor. That's the one that annoys me more. I think Navigation is all I use that would access GPS. I don't geotag, and most other applications are set to locate using the network radio rather than GPS because I don't need them to be as precise.
     
  9. RiverOfIce

    RiverOfIce Banned

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    Well the facts of the matter is this, gps, not including the 3g radio useage for tower, uses between 10-50 milli amps. Which to your phone is not all the much. Maybe a total of 1-3% of the power over a over a full charge. So turning it off would give you like 5-45 mins more battery, depending on use. Not a whole heck of a lot. If you run your phone for 10 hours, you just saved yourself 6-18 mins of battery. Run your phone for 24 hours, you just saved yourself, 14-42 mins. (numbers are estimates.)

    For me, not worth turning it off. Wifi is another story, it can suck up to 114 Milli watts, which will dramatically shorten your battery.
     
  10. Mongoos150

    Mongoos150 Well-Known Member

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    I've been told that the GPS chip draws quite a bit of power when left on, regardless of whether you're using a GPS app like maps - I haven't tested this (running a day with GPS on vs. off). Any feedback?
     
  11. jgalan14

    jgalan14 Well-Known Member

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    GPS sucks battery for sure even tho your not busing applications just by using search it sucks it up because the OS was design like that is my guess( like using search ), I could have my GPS on all the time on my BB touch and never suck battery like this phone does or a Android phone for the matter, now using WiFi actually saves you battery if your conect it to the network in the place your at ( coffee shop, mcdonalds, home ,etc) cause WiFi is closer then any antenna on 3, there is an app the locates where you at and connect to WiFi as soon as you get there and save yoy some juice
     
  12. Rob_A

    Rob_A Well-Known Member

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    The first month (June) I would turn my gps off whenever I wasn't using it.

    Now (July) I leave the gps on all the time and really don't notice a difference.
     
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  13. ejchis

    ejchis Well-Known Member This Topic's Starter

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    This is handy information. Thank you. Maybe I'll run some tests over the next couple of days to see if it is worth flipping off. The only problem with testing is that my phone usage is never consistent day-to-day.
     
  14. RiverOfIce

    RiverOfIce Banned

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    It will depend on usage.

    For the most part, it will suck less then 1% of power over the long run, or at least for me it does, and I abuse the heck out of it.
     
  15. The Dorian

    The Dorian Well-Known Member

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    Same here.
     
  16. as329

    as329 Well-Known Member

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    I run both all the time and get 12-16 hours standby with 3-5 hours of use, be it calling, texting, surfing or playing games...most of that drain is at work with no wifi, using the 3G for internet (I goof around a lot at work) which burns more battery. At home almost all day today, on wifi, I'm at 63% at 6.5 hours off charger. About 1.5 hours of display time, couple calls, text, email, Home Run Derby, checking my daughter's location on latitude as she is visiting NYC, etc. That's a pace of about 17 hours and 4+ hours of "use", which is fine with me.
     
  17. LS1

    LS1 Well-Known Member

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    Wifi - Use an app called Y5 - it will automatically switch wifi on and off depending upon your location (uses cell towers, not GPS for location). When you're in an area your phone remembers a network, it switches on. It's seamless, and using Wifi is much more battery efficient than 3G or 4G.

    GPS - only uses power when activated by an app that needs it. Leave it on.
     
  18. whtge8

    whtge8 Well-Known Member

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    I always have my GPS on and I get great battery life. I use WiFi at home and school but anywhere else is 3G and as mentioned I get battery life, never less than 16 hours.
     
  19. Vincent Law

    Vincent Law Well-Known Member

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    I'm sure this has been answered like 5 times now, but simply put:

    Wifi:

    If you're in an area with wifi service, turn Wifi on. It will always save you power over using 3G/4G.

    Otherwise, for most battery performance, turn it off.

    GPS:

    Unless it is ACTIVELY using GPS (you see the satellite image in the bar), it is NOT USING ANY POWER. Some people swear it does, but they are incorrect. The whole point of that icon is to inform you the chip is on and locating satellites. Leaving "location services" on will not impact your battery life. Only turn GPS off if you don't want applications using GPS to find you, or waste battery when doing so.
     
  20. Karl_in_Chicago

    Karl_in_Chicago Well-Known Member

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    Same here.
     
  21. SolApathy

    SolApathy Just another robot Guide

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    Keep in mind that GPS is a PASSIVE service in itself. The satellites provide the signal. The only time you are really using any noticeable power from the GPS RECEIVER is when it is asked to poll the GPS sensor (by an application) for signals & use the software to calculate your position.

    That is what takes up processing power & in turn drains your battery, especially if you are using real time polling (navigation) vs timed polling ( Weather/geo-tagging- every 5 seconds/10 seconds/5 minutes/1 hour)

    There is no need to turn the GPS off...
     
  22. Rigmaster

    Rigmaster Well-Known Member

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    GPS is passive, but it does kick on quite a bit. When I'm out walking my dog, it pops on several times in a 20-min walk. GPS radios tend to chew battery power regardless of what device they're in or as standalone GPS.

    I leave mine on all the time, but it kicks on more than I expected and certainly not when I'm doing a specific locate command.
     
  23. JunBringer

    JunBringer Well-Known Member

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    I turn them both off and did notice battery life improvement.
     
  24. Headcase_Fargone

    Headcase_Fargone Well-Known Member

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    I just set up profiles in Locale to turn all that junk on and off when I'm most likely to need it. It's worked out quite well for me so far.

    For instance:
    At home - Ringer loud, WiFi on, GPS off.

    Leave home - Ringer loud, WiFi off, GPS on.

    At work - Ringer off, WiFi on, GPS on.
     
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  25. IPvFletch

    IPvFletch Well-Known Member

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    I leave all 3 on and regularly get 40+ hours from my battery. :D
     

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