GPS, BT, Wifi battery drain when not in use but on?

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  1. Lock-N-Load

    Lock-N-Load Well-Known Member

    Just to clarify, is there in fact battery pull and drain from BT, Wifi and GPS even if you are not actually using them as there no app running needing them and no icon showing them active in the menu bar?

    I am curious if they are sending out polling or searching signals and thus, still draw the battery down? It seem they must, agreed?

    Is it a substantial pull? I kind of want to leave them all on, but have started the habit of having them off and just using a widget to turn each on - 1 by 1 - as needed.. but that is kind of a PITA and I wonder if it is not even necessary?

  2. alamoe

    alamoe Well-Known Member

    There is definitely a drain from them just being on. You're right, when they're on they're constantly searching for a signal and that burns battery power. I only turn them on when i'm using them. IMO Wi-Fi is the biggest drain, followed by GPS, then BT. I guess its similar to a car burning gas just by being turned on, even if you don't mash the gas pedal.
  3. Lock-N-Load

    Lock-N-Load Well-Known Member

    thanks.. I agree.. I just wonder if it is proven out there to be substantial and worth turning them off until needed of screw it and let them all run all the time as it is a minor drain.
  4. alamoe

    alamoe Well-Known Member

    I can't say exactly how much of an effect it would have on your Droid, but i would just test it out. I know the Droid has pretty good battery life but i can almost guarantee you'll see a difference if you leave them on, especially Wi-Fi. If you've already been leaving them all on and get pretty good batt life then you would definitely get even better batt life by turning them off when you're not using them.
  5. ttaylor0024

    ttaylor0024 Well-Known Member

    Actually, I would rank them wifi, bluetooth, GPS. The only time GPS is in use and draining the battery is when its icon is in the notification bar.
  6. Lock-N-Load

    Lock-N-Load Well-Known Member

    you don't think if GPS is "on" it must be sending out little pings looking for whatever app or device wants to use it? You think that it only comes online when an app tells it to. yeah, maybe so.

    But WifI and BT must be sending out pings to try to find networks or other close devices or handsfree or your a network - so agree those must be eating some battery life
  7. Lock-N-Load

    Lock-N-Load Well-Known Member

    oh heck.. then there is the Sync feature which for sure drains when running.

    That being said, my battery shows that the Calendar is a hog - but not sure if that is due to Sync or if just a heavy battery user as the built in battery app does not make that clear - just shows that Calendar is a hog.
  8. Needsdecaf

    Needsdecaf Well-Known Member

    It's actually the opposite. You leave GPS activated, your battery will burn.

    Wifi uses very little power when on but not active.
  9. gotwillk

    gotwillk Well-Known Member

    i've asked this same question about GPS and i was told from multiple ppl that leaving GPS in the "on" state but not having an app that is actively using GPS, does NOT drain battery or much battery at all.
  10. (G)

    (G) Well-Known Member

    It stands to reason that if there's current flowing through a circuit because it's turned on, it'll burn some power. Maybe not much, but it still burns power.
  11. crankerchick

    crankerchick Well-Known Member

    So, what I learned is that GPS is always on. The check mark in settings is only allowing applications to use GPS or not. It's not a switch to enable the circuitry or not.

    I have been doing some of my own (non-scientific) testing of my battery life using the battery history graphs to see my actual usage of BT, WiFi, GPS, Display, Device, etc. Battery Left widget will expose this screen, it hidden in the SDK and can't be found by going through the regular settings. Anyway, so I have been monitoring my battery life first with everything off, then with GPS checked but none of my apps allowed to use it and my life is the same. It takes a hit of course when I let my weather widget use GPS to update every hour, or let the browser use it for location searches, etc.

    GPS definitely drains your battery the hardest for comparable time usage to WiFi and Bluetooth. Just use it for 5 minutes, then WiFi for 5 minutes, and BT for 5 minutes and then check out your battery usage screen and you'll see that it consumes a higher percentage of your consumed battery life. And by use i mean use it, like with maps, not just checking the check box.

    WiFi has two states--On and being used. And having wiFi on, when you put the phone down and the screen blanks out, wifi will disconnect from the access point, and reconnect when you bring the screen back on, saving you some battery life.

    This is how I roll:
    GPS checked but I limit the apps that can use GPS to just the ones i care about having a precise location. Things like weather widgets, my cellular location is good enough for me.

    BT on when I want to use it, and I may leave it on because it's not that big of a battery consumer.

    WiFi is only turned on when I want to use it or when my phone is plugged in to charge.

    The biggest battery hogs are the screen and using GPS.

    Spend some time with an app like Battery Left or Spare Parts--one that will expose the battery history statistics for you--and you will see better which things affect your battery the hardest, and you'll have real numeric usage numbers to support your claims.
  12. crankerchick

    crankerchick Well-Known Member

  13. takeshi

    takeshi Well-Known Member

    No -- GPS doesn't poll anything on its own. It works the opposite of what you're thinking. Apps request use of the receiver.

    Not in my experience. At least, I didn't notice a significant difference when I disabled GPS.

    Now, if an app is actively using GPS (GPS icon in the notification bar) it will definitely chew through your battery. A lot of people don't pay attention to the notification bar. It's entirely possible that an app can be using the GPS receiver when you're not expecting it to. Just monitor the notification bar.

    You don't have to take anyone's word for it. Test it out yourself.
  14. Droidood

    Droidood Well-Known Member

    Based on my experiences I'd say it's definitely not wise to leave WiFi & Bluetooth on all the time. Even though they technically don't draw much power in the ideal situation, I've found one or the other will occasionally bug out and kill my battery very rapidly. GPS is rarely used for more than a few seconds by any application other than maps...

    You can't be THAT opposed to having 2 little widgets on your screen :p
  15. Needsdecaf

    Needsdecaf Well-Known Member

    You are right, of course.

    But you'd be surprised at the number of apps that poll your GPS location when it's on. Unless you're killing all of them, it's going to use battery at a phenomenal rate.

    Besides, it's not necessary unless you need a precise fix. All the widgets will get your location from the towers.
  16. Droidood

    Droidood Well-Known Member

    I've never turned GPS off and have always gotten phenomenal battery life. I guess if you have a weather widget that's constantly checking your location via GPS it would be a huge drain, but I really can't think of many apps that would continually use the GPS receiver :confused:
  17. Lock-N-Load

    Lock-N-Load Well-Known Member

    great, but contradictory info :eek:
  18. Droidood

    Droidood Well-Known Member

    Eh? Where's the contradictory info?

    GPS leave checked, you shouldn't worry about unless one of your apps is constantly accessing it.
    WiFi and Bluetooth should be turned off when not in use.

    As for your Calendar drawing lots of battery, that's gotta be a bug or some kind of weak connection. If it struggles to find or maintain a data connection for syncing I could see the Calendar being blamed. But I update my gmail calendar from my laptop multiple times every day for school assignments, Background Data and Auto-Sync both enabled at all times on the Droid, and the calendar is never responsible for more than a sliver of battery use. Updates appear on the Droid almost instantaneously.
  19. Needsdecaf

    Needsdecaf Well-Known Member

    I give up....
  20. Lock-N-Load

    Lock-N-Load Well-Known Member

    for real?

    some say GPS drains, some not

    some think wifi biggest drain, some say GPS

    a few say BT can drain, some so no worries
  21. Lock-N-Load

    Lock-N-Load Well-Known Member

    BTW, when you say "checked" you mean leave it "on"?

    what pre installed apps poll using the GPS? Maps, Google, etc?

    I have a weather widget that pulls ever 30 minutes - but with GPS off, it just grabs it from OTA, no?
  22. Droidood

    Droidood Well-Known Member

    They're not simple yes or no questions, but after reading through the thread I think everyone still pretty much agrees on the answers.

    - GPS will use a lot only if you have some app that is constantly getting your location via GPS.
    - WiFi has the potential to use a lot if you're moving in and out of different network's ranges.
    - Bluetooth seems to use a noticeable amount if left on, but nothing major.

    If you want a more precise answer for how much Bluetooth uses while "inactive" just leave it on for a day and look for it in your battery use afterwards?

    The answer is yes to all of those.

    Doing a search through Google will cause the phone to check your location briefly via GPS. Google Maps will use it a lot if you're sitting there looking through the maps or if you're using the Navigation feature. I'm not aware of any other pre-installed apps that use location...

    And your weather app should base your location off cell towers if you have GPS off.
  23. crankerchick

    crankerchick Well-Known Member

    If you want more precise answers than what is here, get an app that will allow you to see your usage in minutes of each WiFi, GPS, Screen, Device, BT and judge for yourself. I provided a link to go step by step of what app to get and how to interpret the data provided to you.

    There's no better way to understand the battery life of your device than by testing it out yourself.

    I think the concensus is clear too:
    GPS checked makes no difference on battery life, what matters is what apps you have and if you let them use GPS. BT has an effect of course, but nearly on the level as WiFi, GPS (in use), display, or voice calls. WiFi is better left off unless you need it.

    I have only one app that uses only GPS for location stuff (ShopSavvy) and it insists on periodically using GPS for 59 seconds to refresh my location even when I'm not actively using the program. So I have turned off location searches on it.

    All of my widgets I can say whether to use GPS or cell location and I choose cell towers. Beautiful Widgets doesn't disstinguish, but in looking at my GPS usage, BW is rarely in the list, so it must use mostly cell towers. When I check my GPS usage in my battery history, it is usually zero or a few seconds because of the browser (i allow location search and my homepage is google, so everytime i open a new window, the little gps dish appears in the notification area). Other than that, the only time GPS is being used is when I open Maps (which is usually when I want it to be used).

    My battery life is exactly as I suspect it should: unaffected by just having GPS checked (again, it is not a check to turn it on or not, it's just a check to allow other apps to use the GPS).
  24. Droidood

    Droidood Well-Known Member

    Can't stress that part enough.

    Where you are, what you're doing, what apps / widgets you have, how much you're moving around and signal strengths / availability will all influence GPS/WiFi battery consumption far more than simply ON / OFF.

    As far as I know Bluetooth will only attempt to connect to things once it has been paired, so it doesn't waste battery randomly receiving and transmitting signals outside of the temporary "discoverable" mode... but I could be entirely wrong about that.
  25. crankerchick

    crankerchick Well-Known Member

    When I tested my battery life with bluetooth on for the whole day but not paired with anything, in the 14 hour period, BT was on 100% so 14 hours. It was 4% of the consumed battery usage, which for that day my battery had lost 70% in that 14 hours. I had WiFi on for 3 hours 12 mins and used for 2 hours 37 mins that evening when I got home from work and it was 14% of the 70% used. The display was the biggest killer at 35% of that 70% of battery used.

    BT is something I don't worry absolutely about turning off. It's off right now because I have no intention to use it. But if I turn it on later and leave it on, I won't worry about turning it off unless I know for sure I'm done with it for the night. I turn it off when it makes sense to, but don't worry too much about it when it is on (ie more power consuming).

    Now WiFi on the other hand. I keep it off unless need be because it is signficant enough to have a noticeable effect in a shorter period of time.

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