Nexus 7 charging: How long?

Discussion in 'Mobile Devices & Gadgets' started by Eug, Sep 15, 2012.

  1. Eug

    Eug Lifer

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    When I woke up this morning, my Nexus 7 was completely dead. That was a surprise to me, because it wasn't near dead when I went to sleep. So I plugged it in and after a few minutes of charging was able to wake it back up. It read battery: 0. After a few minutes I started surfing with it and what not, but after about 5 minutes I got a screen full of snow and it shut off.

    So, I left it off, to charge. It's been charging around 2 - 2.5 hours and it's only at 15% now. (I turned it on briefly to check.)

    I wonder if there is something wonky with my Nexus 7. I'm using the stock 2A charger and the stock cable, but I seem to remember it charging a lot quicker before.

    I'm certainly not getting this charge time:

    [​IMG]

    EDIT:

    I just came across this thread:

    http://androidforums.com/nexus-7/594627-nexus-7-dead-wont-charge.html

    Similar symptoms.

    Interestingly I had been playing with Stickmount last night, but AFAIK, I had left the USB flash drive unplugged, so it wouldn't have been a source of battery drain.
     
    #1 Eug, Sep 15, 2012
    Last edited: Sep 15, 2012
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  3. dguy6789

    dguy6789 Diamond Member

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    Go to settings and battery and it should say charging and then either USB or AC in parenthesis. If it says USB then unplug and plug it back in and see if it changes to AC. I have noticed some devices charge in USB speed for some reason when plugged into an AC outlet and need to be unplugged and plugged back in again sometimes to fix it.
     
  4. Ravynmagi

    Ravynmagi Platinum Member

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    Because it's discharging so fast and charging so slow, it sounds like it's wonky. Mine charges pretty quick, I'd say 3 hours for a full charge is about right, mine charges less since I rarely get that low.

    My battery life has been pretty excellent. You might have some app going crazy or maybe a hardware defect. Reboot if you haven't yet. Next I'd probably try backing up and doing a factory reset.
     
  5. Eug

    Eug Lifer

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    Almost 12 hours now. 52%, on AC, with the unit off for most of that time.

    Tomorrow is the last day I can get a refund. Maybe I'll do that. Or perhaps I'll unroot and wipe it tonite to see what happens to it. There don't seem to be any wayward apps in the apps list.
     
    #4 Eug, Sep 15, 2012
    Last edited: Sep 15, 2012
  6. vshah

    vshah Lifer

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    try out better battery stats, but if you only have one day left, i would exchange it.
     
  7. Spoooon

    Spoooon Lifer

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  8. BenSkywalker

    BenSkywalker Elite Member

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    Had you deep cycled the batteries at all since you bought it?

    Last couple of 7s I bought I ran them dead then plugged them in, never turned them on, and let them do a full charge- took about 24 hours for them to charge up(each obviously). Since then they haven't come close to going dead, not sure how long it would take now but they are used constantly and only hit the charger every other day.

    If you haven't run them all the way dead and done a full charge, you may have not seen the actual capacity of your battery yet.
     
  9. Eug

    Eug Lifer

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    Never all the way dead, but to less than 10% a few times. With your 24 hours statement it sounds like your experience is similar to mine. However that doesn't jive with the Anandtech review saying it it should take just a few hours, nor my experience with the under 10% to full charges either, which also took just a few hours.

    BTW, after the device hit 52% (after 11+ hours) it charged to full in a couple of hours.
     
  10. BenSkywalker

    BenSkywalker Elite Member

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    This can make a *huge* difference. It's a bit complicated, but batteries aren't like gas tanks, they work on chemical reactions, and ideally they will be 'trained' so the device they are in knows when they are actually dead and when they are actually full. With advances in technology, the devices we have today do a better job at 'guessing' out of the box, but it isn't comparable to an actual 'deep cycle' recharge.

    At this point my 7s will charge to full in probably four hours from under 5%, I will kill them every other month or so and do another deep cycle on them which will again take ~24 hours(probably, haven't done a second deep cycle on them yet).

    The device must be powered off for a deep cycle charge to work properly, and stay off(you can look at the battery indicator on the 7 as long as you don't boot it, mine took ~10 hours to go from 98% to full). Now the batteries last significantly longer then my first run down(both of them indicated they were over 50% when unboxed, both dead in ~4.5 hours looping the Transformer movie at max volume that came with them, they now are closer to 6-6.5 hours under the same situation).

    Here is a link that gives a brief breakdown-

    http://www.atbatt.com/faq/1.asp

    After you do a deep cycle, you should be in line with Anand's test results in terms of charging(ball park) but you are likely to see a sizeable performance improvement.

    Pretty much, you may have only been using from 2%-38% of your Nexus 7's battery based on what it indicated, a quick charge works fine when the device knows the exact parameters of your battery, but if it doesn't the only way to find out what the upper limits of it are are to 'trickle charge' it so you don't damage the battery. That is why it takes so long when you run it all the way dead. Once you do this once, your device will know exactly where the battery ideals are and you should be good to go for a while(honestly, the once every couple months that I do it is probably a bit excessive, I can tell you one of my kids got an identical phone to mine and was getting half the battery life I was after eight or nine months, he deep cycled it once and was back to in line with mine).
     
  11. T_Yamamoto

    T_Yamamoto Lifer

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    I'm pretty sure most devices stop charging at 99. My gnex will never go above 99 (rooted. Deep cycled)
     
  12. Eug

    Eug Lifer

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    If anything my battery life may be worse now. I've gone from 100 to 49 in about 2.5 hours of just surfing, with the occasional lolcat video.

    Before this incident, it'd be at say 80% with similar usage.

    Mind you, I left it on all night with the screen off and it was still 100% in the morning.

    So maybe its just that the battery indicator is borked. Either way it is pretty damn irritating.

    ---

    Down to 46% since starting this post.

    P.S. I deep discharged my first Nexus 7 and it didn't show the same behavior, and I've never seen this behavior with my iPad or iPhone either. I'm beginning to wonder if the Nexus 7 is just a poor quality product, given that my first two had the screen lift issue.

    Today is the last day for the return. If I do return it, the question is if I go for number 4 or just cut my losses and wait for the next 7" Samsung or something.

    Now down to 44%.
     
    #11 Eug, Sep 16, 2012
    Last edited: Sep 16, 2012
  13. Demo24

    Demo24 Diamond Member

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    There's something quite wrong, either a stray app or a hardware issue. I'd factory reset it.
     
  14. soccerballtux

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    yes check stray app
     
  15. Eug

    Eug Lifer

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    I couldn't find any stray apps, and reboots didn't help.

    However, I've now factory reset it. In fact, it's now no longer rooted, and it's now locked. Behaviour so far seems more normal, but we shall see.
     
  16. Spoooon

    Spoooon Lifer

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    I would get a return and give it another go just in case. I think it's a high quality product suffering at times from manufacturing difficulties. Which is definitely frustrating, but mine has filled a niche I didn't realize I had. :D
     
  17. Eug

    Eug Lifer

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    Too late now. Stores are closed and today was my last day. If I return it, it will have to be under warranty now, which is fine I guess. 50 weeks left. :)

    I was a bit worried that unit #4 would give me a screen lift issue or stuck pixels or something. (Luckily, this one has neither.) It seems Google/Asus's QA on these isn't the greatest.
     
    #16 Eug, Sep 16, 2012
    Last edited: Sep 16, 2012