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  1. Thread Author  Thread Author    #1  

    Question Battery drain, new issue

    So I've been having battery drain issues over the last 10 days. I downloaded OS Monitor, but nothing is jumping out at me, and I still don't know what I'm doing.

    I also downloaded the smart quick settings app.

    I normally leave the screen brightness as low as possible unless the charger is connected while I'm using it.

    I never turn on Bluetooth, and I turn Wi-Fi of if not using it. I try to be very conservative with energy, but around 10 days ago I noticed a big drain one day, while off- charger and on Wi-Fi. I thought maybe it was over, but I'm still having trouble. Friday night I finally began notating the drops, and how slow it charges now.

    I've deleted all apps I downloaded the day I noticed it, and a few other ones besides.

    I bought my tablet mid September and until recently, just reading Pocket, PDFs, etc with no Wi-Fi on used about 7% an hour. WiFi web browsing was about 10%. If using web while charging, it works usually gain about 14%ish an hour despite Wi-Fi on. In sleep mode (which I use more than turning it off), it gained about 25% poet hour of charging, asleep with WiFi off.

    But now I lose anywhere from a quarter to a third more energy, WiFi or not!

    Seems to use about 10% or slightly more, even reading offline. Wi-Fi browsing is probably 14% or more now. The first day I noticed it, I was using Wi-Fi/discharging for 3 hours. Before, that would have put me down to around 70% from a full charge, but instead I was at 61/62%.

    Smart quick settings points me toward " Android task manager" when I try to see what tasks are running. I don't know if it would be anymore helpful than OS Monitor. It also says cellular data is on, but I assume that's a weird fluke, since I'm on a 16gb n7 with no such plan/ability.

    Also, asleep, it still charges around 25%, no Wi-Fi.

    I've heard the battery gets crappy for a week after updates, but I think this started a bit after my last update. And it has gone on longer than a week.
    The first day I noticed it, the back seemed warmer in my hands than usual. Haven't noticed it since, could've been a subjective impression, maybe I've gotten used to it.
  2. #2  

    Default Re: Battery drain, new issue

    It should not have that cellular on and that may be draining you have you always had cell data on or is this the first time you noticed it? You could try to put your tab on airplane mode and run videos for a while to see how fast your battery uncharges and to check if it is a hardware problem. Also check for rogue apps that may keep cell data or wifi on
  3. Thread Author  Thread Author    #3  

    Default Re: Battery drain, new issue

    It's never had cell data. I don't have a plan, and this is supposed to be Wi-Fi only.

    When I turn the cellular thing of in the quick settings app, I'll come back and it's on again. I don't even know what it is. There isn't any cell data, and blue tooth is off.
  4. #4  

    Default Re: Battery drain, new issue

    i have the same problem as you.....sometimes it charges super fast..sometimes it takes ages......but whatever it is, battery drains really quick even on stand-by mode.....
    i'm very tired of this ...any day, i shall just through my nexus and get an ipad mini instead...at least it is a solid machine....
  5. Thread Author  Thread Author    #5  

    Default Re: Battery drain, new issue

    This WAS a solid machine until less than 2 weeks ago.. I'd just like to get it back to where it was.

    My budget won't accommodate anything with an "I" in it.... and I've heard the mini is recycled iPhone parts with poor screen resolution.
  6. #6  

    Default Re: Battery drain, new issue

    Are any of you using a charger other than the one that came in the box? The charger that came in the box is a pulse charger and will typically take much longer to recharge. It helps the battery take on a more full charge and extends the life as well.
    Thanked by:
  7. Thread Author  Thread Author    #7  

    Default Re: Battery drain, new issue

    I'm using the default charger.

    And my slow charging issues are an extension of a heightened battery drain over the last week and a half.
  8. #8  

    Default Re: Battery drain, new issue

    Quote Originally Posted by repligation View Post
    Are any of you using a charger other than the one that came in the box? The charger that came in the box is a pulse charger and will typically take much longer to recharge. It helps the battery take on a more full charge and extends the life as well.
    Where are you getting this info? I didn't see anything on the charger itself to indicate it is a pulse charger. Searching didn't turn anything up either. Can you point me to a source?

    Also, I've seen manufacturer's pages that indicate pulse charging is not recommended for LIPOs. Generally LIPOs are charged at a constant rate until terminal voltage is reached and then current is reduced while holding the voltage constant. However, the charging control circuit is usually in the device (like the N7). The thing people call a charger is really just a power supply - in this case 5V at up to 2 Amps. No real smarts in it other than maybe signal voltages on D+ and D- to indicate max current available.

    And yes, I've used several different USB chargers with my 2 N7s. They all seem to work fine if capable of delivering 2 Amps. I've used "cell phone" USB chargers which are typically only good for 1 Amp and the N7 seems to tolerate them but at a slower charge rate (about 1/2).
  9. #9  

    Default Re: Battery drain, new issue

    Really is this info anywhere because I have used my HTC phone charger and my brothers samsung charger and they seemed to charge it a lot faster. I didn't use them anymore because I don't want to mess anything up but is this charger any different than any normal 5v 2a charger?
  10. #10  

    Default Re: Battery drain, new issue

    I believe the N7 charger (power supply) is a plain vanilla 2A, 5V device. Nothing special.

    Like I said, I've used a number of 2A chargers and they all seem to work fine. In my house I have an N7 charger, a quad 2.1A charger, the 1A charger that came with the droid razr maxx, a 2A car charger, 3 or 4 "1A" chargers (quotes meaning I don't trust the specs) and a couple of 1A car chargers. The 1A chargers will charge the N7s slowly. The 2A chargers are much faster. I get very fast charging from the N7 charger (about 1 hr to go from 40% to full). I often put my phone on a computer USB port and it slowly charges up. Bottom line, more As equals faster charging and I have yet to fry anything. Devices I charge with these USB chargers: 2 N7s, 2 iPad 2s, a droid razr maxx, my kids phones, portable speakers, BT headphone set.

    If your N7 stays cool when charging then you have nothing to worry about.
    Thanked by:
  11. #11  

    Default Re: Battery drain, new issue

    Yes, you are correct the pmic is located within the N7. It can and does employ pulse when needed
    A PMIC can use pulse-frequency modulation (PFM) and pulse-width modulation (PWM). It can use switching amplifier (Class-D electronic amplifier).
    Power Management IC - Wikipedia, the free encyclopedia

    Nexus 7 - Wikipedia, the free encyclopedia

    The included charger is rated at 5V and 2A. Another tablet charger would probably suffice, but a typical phone charger is usually only about 1A and that in itself can be a problem.

    A Li- ion Polymer battery will have different requirements depending upon its depth of discharge. This is the job of the Power Management Integrated Circuit designed by MIP. Much of the time it will be charging with Constant Current and Constant Voltage at which the charge rate will appear linear, but at the end of the charge cycle the PMIC will switch to something which better suits the life of the battery.

    The real answer is more complex in that the PMIC is whatever the battery and phone needs at the time.

    The rectifier circuit in the power adaptor/transformer can very widely in what it delivers to the device. I would be careful using other USB chargers for this device.
  12. #12  

    Default Re: Battery drain, new issue

    Where i stay, nexus 7 and ipad mini wifi 16gb is about the same price. ...i've my google current disabled , day dream off, location off, all the cool feature i turned off which was the main reason why i bought nexus......
    still, i have less than 4 hours of usability ......anyway i'll still wait for updates from google....next year when mini comes out with retina or better display..i shall get that......
  13. #13  

    Default Re: Battery drain, new issue

    Quote Originally Posted by shontrashi View Post
    Where i stay, nexus 7 and ipad mini wifi 16gb is about the same price. ...i've my google current disabled , day dream off, location off, all the cool feature i turned off which was the main reason why i bought nexus......
    still, i have less than 4 hours of usability ......anyway i'll still wait for updates from google....next year when mini comes out with retina or better display..i shall get that......
    "Where I stay" the iPad mini is over $100 more and is still the inferior device. You may have a poor battery in which case you should contact Google to see about an exchange. Sorry to hear you are having a bad experience.
  14. #14  

    Default Re: Battery drain, new issue

    OK, I hear what you are saying repligation but no LiPo chargers (Power Management ICs) do that. It's simply not how LiPos are charged. There are numerous battery supplier sites out there that describe LiPo charging strategies which are for the most part pretty much the same (constant current to terminal voltage).

    I've yet to find a USB style "charger" that doesn't work with the N7. They all appear to be switch mode supplies and have current limiting that prevents over current from damaging the supply (like when you plug an N7 into a 1A supply).

    To the original poster - it does sound like you have a defective N7. I would try to get a replacement.
  15. Thread Author  Thread Author    #15  

    Default Re: Battery drain, new issue

    The only support I found on the site regarding the nexus 7 was advice on sending it back, which I'm not quite sure is necessary yet.....
  16. #16  

    Default Re: Battery drain, new issue

    Try to get BetterBattery Stats from Play Store or XDA Forums for free (just google "BetterBattery Stats xda download").
  17. Thread Author  Thread Author    #17  

    Default Re: Battery drain, new issue

    Okay, is that simply a monitor, or is it also some kind of calibration/power saver app? I've heard of it before.

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