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  • 1 Post By natehoy
  1. Thread Author  Thread Author    #1  

    Default Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    ... have dodged a bullet.

    So here is the story.

    I was using my nexus 7 and got a warning I was down to 4% charge. I know, I should have had it on the charger way before it got that low. My bad.

    Well I figure I will put it on the charger when I get another warning. I am going along when poof, it shuts down. I am thinking ok. I will just hook it up to the charger. No biggy. I hook it up to the charger and push the power button. Nothing happens. I am thinking oh great. I am kicking myself for not putting it to recharge when it was down to 4%. It's dead and I will have to return it to Google.

    So, I hold the button longer. It takes a rather long time but the Google screen comes up much to my relief. That relief does not last. It goes to the nexus screen and seems to take much longer than I remember to start. When it finally does start it gets to the lock screen then proceeds to shutdown. Now I am in full panic mode. Has the micro USB port gone bad? Has the charger gone bad. Has letting the battery go to 0 killed its' ability to charge. All sorts of things are going through my head at this point.

    I hold the power button. Again it takes much longer for the Google screen and the Nexus screen to come up. Again, it finally gets to the lock screen. And again it shuts down almost right after it starts. At this point I am getting even more worried. Ever single start up all I get is a short interval before it shuts down. I check the battery and it says 0 charge.

    I try to calm down and decide to let it sit for about 5 minutes before I attempt to turn it on. Five long, long minutes pass. I turn it on and am greeted with a charge of 3%. Great, I tell myself. I am out of the water. I do a couple of tests with some of the apps to see if they are working ok. They seem to be and I check to see how much more charge I have now. To my horror the charge is at 2% now. I am back to panicking now. I have it on the AC charger. It should be gaining a charge not losing it. I notice instead of indicating it is charging AC it is indicating it is charging USB. Oh great. I will be stuck only being able to charge USB now.

    Again I attempt to calm down. I think about disconnecting the charger and reconnecting it in hopes it will charge AC not USB. But I, worry in that short time it will discharge to 0 again and I will really be screwed. I decide I have to try and get it charging AC so I disconnect and reconnect. Afterwards I click the power button and am great with the charge screen. the indicator starts way at the bottom. I expect that as it only had 2% charge. I decide to give it another 5 minutes and check back. I walk away only to hear it start up out of the blue. I am thinking uh oh it's that endless rebooting cycle others mentioned. Panicking again. I turn it off and this time it stays off. when I turn it on again it has a 5% charge. I forget to check if it is charging AC or USB. At that point I decide to give it 10 minutes before restarting.

    With 10 minutes having passed I turn it on and I am greeted with a 9 percent charge and indicating that it is charging AC. I am still a bit worried as the charge screen preboot is still showing no charge in the graphic. But, I figure maybe it won't show partial charge until it hit perhaps 15% and again I turn it off and wait 10 minutes. I turn it back on and it now has a 13% charge. Still no change in the preboot charge screen.

    Now I decide to wait 20 minutes. Turn it one again and I finally see an indication on the preboot charge screen. I boot up the tablet. 22% Charge. I am beginning to finally feel I am out of the woods. It's getting late but I decide to wait another 20 minutes and check again. This time it says a 34% charge.

    At this point it is well past midnight. I am still not 100% sure I am out of the woods. But, I decide instead of turning it off that I will risk just putting it to sleep and letting it finish charging over night.

    To my relief when morning comes my alarm goes off normally, well almost normally. it gives me the time but no weather. Bug in the App I am thinking. I check the battery. Woohoo 100%

    Now I am not saying that this will work with for everyone having a battery issue. In fact, I think I was rather fortunate. I plan never to let the charge go down that low again. When I get to the 15% warning that puppy will be either on the charger or off if I am not near an outlet.

    I don't want to repeat that nightmare ever again.
  2. #2  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    There is this one guy helpful person (EdsonDJ) who said:
    This just happened to me right now then I saw this thread and I wanted to share what I did.

    - Assuming your unit can boot long enough to do this, press and hold all the buttons (I'm not sure on the exact button combo) to give the device a hard reset.
    - Keep holding the buttons till it reboots to the bootloader.
    - Cycle through the menu selections and choose to power off the device.
    - Unplug then re-plug the charger.
    - You should now see the battery-charging icon. It shouldn't boot up on its own anymore. Just let it sit and charge to full capacity.


    Sent from my Nexus 7 using Android Central Forums
  3. #3  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    I would say that as soon as you start using the device while charging it either completely stops charging or goes to low-voltage charging. That could explain why at the first time it shut down immediately.

    I don't know how the Nexus 7 does it, and it seems that here the behavior of devices changes. My iPhone always charges, even when I use it. My PS Vita shows a more lucid battery with a little voltage-line in the middle, indicating it won't be charged, but even with battery on low, it won't die. That means it either goes on low-voltage to only give the system enough power to operate, or it simply delivers the power directly to the system while ignoring the battery. Very unlikely, but possible.

    So I would recommend: if you don't really really really need to use your tablet while it's charging - don't use it. Leave it there till it's charged.

    You don't like it when your parents/kids/spouse/boss wakes you up in the middle of the night, and neither does your Nexus 7! Night time is sleep time, and sleep time is your time to recover/recharge. So the time your devices recharge is their sleep time.

    So give your devices a break Believe me, once you have kids you know how your devices felt when you wouldn't leave them alone while charging
  4. #4  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    I've had mine get that low and die on me. I just plugged it in and did something else while it charged.
  5. #5  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Quote Originally Posted by kimikookskookis View Post
    I would say that as soon as you start using the device while charging it either completely stops charging or goes to low-voltage charging. That could explain why at the first time it shut down immediately.
    Mine charges at 2.1 amps just fine while I am using it. Takes only a little over 2 hours for a full charge and I charge it while it's running and me playing on it ALL THE TIME.
  6. Thread Author  Thread Author    #6  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Funny Kimi,

    I actually let is sleep at night. But don't turn it off as it is my alarm clock. The only reason I kept checking over and over that one day was because I was worried I had messed up the battery letting it go do zero % charge.

    Sometimes I put it on the charger when it hits 15%. last night it was at almost 60% when I put it on the charger. I didn't want to have to charge it during the day today.
  7. #7  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    I'd be really, really surprised if you could damage the battery by letting it get to 0%. Lithium ion batteries are fragile, but manufacturers always put safeguards in so that you cannot do a deep discharge and kill the battery. You want to kill a Li-ion battery? Go fly model airplanes or drive R/C cars. They have massive battery packs and usually have no safeguards against deep discharging... One mistake and an expensive battery will never be the same again.

    But in a consumer gadget, they protect you against this. I have run my N7 down to the shut-off point a coupe of times and it has never been the worse for wear... the same with a dozen laptops, phones, and other Li-ion powered gadgets.
  8. #8  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    There shouldn't be anything wrong with completely draining your battery. If anything, by not charging it until the last minute you're probably extending your battery life. Most cell phone/tablet batteries are only good for 300 to 500 cycles before they start losing full capacity.

    Disclaimer: The first sentence is guessing. I don't know for sure that running a battery down until 0% will not harm your battery. The rest is from an article in AC.

    Sent from my Nexus 7 using Android Central Forums
  9. Thread Author  Thread Author    #9  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    My impression about this whole 0% charge issue is that it is software related. Hopefully something google will address in an upcoming patch. All I know is that is a nightmare I don't want to face again.
  10. #10  
    natehoy's Avatar

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    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Quote Originally Posted by AndroidOsAppsandMore View Post
    My impression about this whole 0% charge issue is that it is software related. Hopefully something google will address in an upcoming patch. All I know is that is a nightmare I don't want to face again.
    EDIT TO ADD: My diatribes after this are lengthy and rambing. You can read the following paragraph and skip the next three posts from me in this thread safely if the details don't interest you.

    Plug Lithium-battery units in whenever it's convenient, and always when they tell you to. This is all you really need to know about proper battery management, because the device knows what it needs and all you need to do is what it tells you to do. If they shut down on their own because you ignored their advice, no harm has been done, but do give them some quiet time on a charger so they can build a safety reserve in the battery. The device is trying to protect your battery; help it out by listening. If they tell you it's not time to start up yet, give them more time. They'll tell you they are not ready yet by turning themselves back off when you hit the power button.


    --- warning - much reading ahead...

    The device allows the battery to run down to a very low percentage, but since it drains power to start it back up the software is probably designed to not allow the device to start unless it's at a slightly higher percentage.

    Battery charge percent is generally read by how many volts the battery is currently capable of feeding.

    A Lithium battery has a range within which it can be charged. So let's say the battery goes un-rechargable-dead once the cells reach 2 volts, and will go to "thermite mode" at 10 volts if further charging is applied. The phone manufacturer has a vested interest in not allowing either to happen, so they build in a safety factor, and call 3.5V "0%" and 5V "100%".

    If you bring the phone down to 3.5V and it shuts down, whether you have it on a charger or not, you might easily bring the battery down to 2V if you attempt to start it, because startup is pretty energy-intensive. So the bootloader might have its very first instruction be "IF CHARGE_VOLTAGE < 4V THEN TURN_OFF_RIGHT_GODDAM_NOW!" 4V might read as much as 15% (which is the point at which it probably started really bugging you about being plugged in).

    So if you've allowed the device to discharge to the point where it shuts itself down, you really, REALLY want to just leave it on a charger for a good 10-15 minutes before you touch it. Preferably more.

    Pressing the button longer simply override the bootloader and told it that you wanted an unconditional startup. That code is there in case something is wrong with the bootloader, and bypasses the battery checks. As soon as the actual operating system took over, it saw the voltage and said "Crap! We need to shut down NOW!" because the restart forced the battery back down to below operational minimums.

    So, to be blunt, you caused your own panic by forcing the unit to start up before it was "ready", which dropped the charge back down to or below the "need to turn off" level.

    Plug it in before it shuts down, or give the poor thing enough time to build a safety charge before you start Johnny Jackrabbiting on the darned power button.
    Last edited by natehoy; 12-10-2012 at 04:07 PM.
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  11. #11  
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    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Quote Originally Posted by gaijin82 View Post
    There shouldn't be anything wrong with completely draining your battery. If anything, by not charging it until the last minute you're probably extending your battery life. Most cell phone/tablet batteries are only good for 300 to 500 cycles before they start losing full capacity.

    Disclaimer: The first sentence is guessing. I don't know for sure that running a battery down until 0% will not harm your battery. The rest is from an article in AC.
    Both are guessing, and (sorry) both are wrong.

    Running a Lithium battery down to 0% will absolutely kill it in a very real and permanent sense unless you have some specialized equipment to jump-start the battery. Fortunately, the device being in "shut-down mode" may INDICATE 0% to you, the user, but is nowhere near the actual battery-killing 0%. So it's perfectly OK to let the unit shut itself down. That is, unless you then proceed to try and force-restart it repeatedly, because that CAN drain the battery down to the point of death.

    Running a Lithium battery down to "shut-down" is not immediately fatal to the battery, but is also not terribly good for it. There are a given number of cycles in a battery, that's true, but two charges from 20% to 70% is the same as one charge from 0% to 100% for the sake of calculating "cycles". Lithium batteries are susceptible to heat damage, and also to small damage to the cells when the charge range falls too low or gets too high. Running it down to "shut-down" is harmful to the battery in the long term. Not by a lot, but by a small amount that adds up. So is maintaining a battery at 100% charge all the time, which is why you want to run laptop batteries down to 40-50% and pull them out of your laptop if your laptop will be on AC power most of the time if you care about the expense of replacing batteries.

    The net result of all this complex discussion is, however, that by and large your device is programmed to get pretty decent battery longevity no matter what you, the user, do. So you can go about all these complicated and inconvenient rules for long battery life, or you can just plug it in to a charger when a charger is available, turn it off (sleep mode is generally OK) before it turns itself off, and don't leave it sitting on a charger for days at a time.

    The device's software is designed to ensure that, as long as you don't go out of your way to outsmart it, there's honestly not a lot you can do to damage the battery or extend its life.

    "Use it if you need it, don't forget to feed it"
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  12. #12  
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    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Quote Originally Posted by horseflesh View Post
    I[...]manufacturers always put safeguards in so that you cannot do a deep discharge and kill the battery. You want to kill a Li-ion battery? Go fly model airplanes or drive R/C cars. They have massive battery packs and usually have no safeguards against deep discharging... One mistake and an expensive battery will never be the same again.
    I wanted to reiterate the point that one of those safeguards is a voltage test very early on in the bootloader process that checks voltage and, if it's below a defined level, turns the unit off very quickly before the charge is allowed to drop even further by going through an energy-intensive startup routine.

    You can bypass that safeguard (the "mistake" part) by pressing AND HOLDING the power button to force a startup. It is theoretically possible, charger or no, to run the battery down into the death zone by forcing a restart on a known-very-low battery. That function exists so you can start a unit with an entirely dead battery on a charger to get your data off it, or if you intend to run the unit on AC power permanently.

    If you tap the button and it responds at all but then shuts down, wait 15 minutes at least before you try again.

    If you know it's been on the charger for a long time (let's arbitrarily say 15 minutes on the provided 2 Amp charger with the provided cable that can actually be guaranteed to deliver 2 Amps, 1/2 hour on an lower-amp aftermarket charger or the stock charger with a different cable just to be safe) but it refuses to start, press and hold the power button to try and force-start it (there may be many other reasons why the bootloader might not respond to input, so if you are pretty sure there's a decent charge on board, it's perfectly OK to try and force-start it).
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  13. #13  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    This is beginning to sound like a Playbook thread. Visit that forum to see some useful comments particularly from the Battery Guru app developer.

    Sent from my Nexus 7 using Android Central Forums
  14. #14  
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    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Quote Originally Posted by jpash549 View Post
    This is beginning to sound like a Playbook thread. Visit that forum to see some useful comments particularly from the Battery Guru app developer.

    Sent from my Nexus 7 using Android Central Forums
    '

    Or, for all you ever wanted to know about all of the various battery technologies, visit Basic to Advanced Battery Information from Battery University <-- awesome site chock-full of good information.

    The Nexus 7 and almost all portable electronics use variations of a Lithium-based battery.

    How to Prolong Lithium-based Batteries - Battery University
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  15. #15  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    natehoy, that is an impressive and helpful set of posts. Just curious, is this knowledge from actual work/career/school experience, or is it from reading up?
  16. #16  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Seems you are a worry wart!
  17. #17  
    natehoy's Avatar

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    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Quote Originally Posted by B. Diddy View Post
    natehoy, that is an impressive and helpful set of posts. Just curious, is this knowledge from actual work/career/school experience, or is it from reading up?
    Reading up and a few mistakes of my own guiding me away from what not to do. :-)

    Sent from my Nexus 7 using Android Central Forums
    Phones: BB 8820 -> BB 8310 -> HTC Thunderbolt -> LG Optimus G Pro -> Moto X
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  18. #18  
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    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Quote Originally Posted by Eduardo06sp View Post
    There is this one guy helpful person (EdsonDJ) who said:
    This just happened to me right now then I saw this thread and I wanted to share what I did.

    - Assuming your unit can boot long enough to do this, press and hold all the buttons (I'm not sure on the exact button combo) to give the device a hard reset.
    - Keep holding the buttons till it reboots to the bootloader.
    - Cycle through the menu selections and choose to power off the device.
    - Unplug then re-plug the charger.
    - You should now see the battery-charging icon. It shouldn't boot up on its own anymore. Just let it sit and charge to full capacity.


    Sent from my Nexus 7 using Android Central Forums
    This worked perfect for me. Thank you so much. You have saved the day!
  19. #19  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Woh... Let me get this straight... So you ran your battery low, then it died and you started worrying that it wouldn't work again? So then when you restarted immediately... you wondered why the battery wasn't charged yet? Then just to make sure... you did this 5 more times> So being as sharp as you are, you noticed the longer you let it charge the longer the battery lasted? Hmmm, well that was a very insightful realization, if I do say so myself.

    I'm glad you were able to deduce such a thing. So your saying, if I let my battery charge longer this longer charge will allow the tablet to work longer? Phew! I was hoping I wasn't alone on this cause I noticed the exact same thing. I guess I'm getting the hang of this battery thing after-all. Most batteries in use today can be recharged I guess. Who would have known!

    After experiencing such a strange occurrence I'm glad you ran to this message board to share your story. Also I am so relieved that you dodged such a big "bullet". Also I'm glad you will never repeat the "nightmare" of having a battery run out. Dead batteries are so terrifying they keep me awake at night.

    This was truly the most entertaining 912 words I have read in months. Your awe inspiring story only took 4,420 characters. Let us know when you get on Jeopardy. Please!

    1. Use a tablet for a long time
    2. The battery dies
    3. Plug in the battery
    4. Become astounded when the battery isn't fully charged after 20 seconds
    5. Realize the relationship between charging time and battery life
    6. Being terrified about losing 20 minutes while your tablet charges
    7. Now you are not saying this will work for everyone? But if your battery dies... charge it over night right?
    8. While the battery is charging you are not sure if you are out of the woods?

    YOU ARE PRICELESS! Thanks for sharing!

    I had to signup to this forum to explain how much I enjoyed reading your post. Truly awe inspiring!
  20. #20  

    Default Re: Nexus 7 Shut down due to 0 Battery Life. But, I seemed to...

    Yeah this whole thread was very informative. What world am I living in?

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