Battery life drops from around 40% to 15% super quickly for no reason - Nexus 7 General

I got a full stock N7 16GB 4.2 OTA which I'm not planning to root or flash (that's what my One X is for =P).
I noticed that quite often if I leave my N7 for a night with about 40% battery life, in the morning it will fully shut down with about 14% battery life remaining. Checking battery usage I see a sharp, almost vertical drop. Something's destroying battery when it gets about half way.
Anybody else had this issue?
Screenshot attached.

Try and fully discharge and charge it a couple of times. The battery may be poorly calibrated. U can use a battery drainer if you are impatient. https://play.google.com/store/search?q=battery+drainer&c=apps

DarkDvr said:
I got a full stock N7 16GB 4.2 OTA which I'm not planning to root or flash (that's what my One X is for =P).
I noticed that quite often if I leave my N7 for a night with about 40% battery life, in the morning it will fully shut down with about 14% battery life remaining. Checking battery usage I see a sharp, almost vertical drop. Something's destroying battery when it gets about half way.
Anybody else had this issue?
Screenshot attached.
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I don't know which update it was put in but it seems Google have added something that shuts down the N7 automatically at 20% to save the battery. I don't know if this is for every unit or not but it's been doing it for me and a few friends who have them too. I guess this is to save the battery as it can affect the recharging efficiency and the battery will die faster than normal if you allow it to drain further.
From your picture it looks like it's doing as it should, shutting down at about 20%, and then guestimating the battery stats, which fools the reading. However dropping from 40% to 20% overnight sounds like you have one or more rogue apps installed causing some serious drain, unless it's something you know/want to be running of course.

Related

first 25% of battery drops fast?

Ok so this is what i noticed has been happening with my phone...
I wake up in the morning and i unplug my phone from charger at 100% battery life...
after about 1-2 hours of no use (outside of occasional check of time) and no programs running i notice that 25% of life has diminished...
i have turned 3g off and done most of the kaiser tweak settings that help with battery life. for the rest of teh day i can use the phone and battery life runs normally but it seems the first 25 to 30% drops real fast without use
is everyone experiencing this? is it normal?
KP
The problem lies in your first sentence. "I wake up in the morning and unplug my battery." You are charging your battery too much thus killing it's battery life. I only charge my phone in the day while I'm at work. That way I can unhook it when it's fully charge. I would go on ebay and type in OEM battery Kaiser. You can pick one up for 15-30 dollars new.
From what I understand. Leaving your battery in the charger when it is fully charged should not damage the battery as long as its not there for an excessive amount of time but i might be wrong. Either way i have no way of charging the phone during the day as im on the go most of the time so this would mean even if i get a new battery it wont matter because it wile eventually do the same as i have only used this phone for about 3 or 4 months now. any other possibilities or solutions?
or should i just take it as it is and just buy a new battery maybe a bigger seido?
I thought Lithium ion batteries have overcharge protection. I charge mine overnight which I am sure a lot of others do also with no negative effects.
netboy said:
I thought Lithium ion batteries have overcharge protection. I charge mine overnight which I am sure a lot of others do also with no negative effects.
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I do... Maybe I shouldn't?
I would hope it has Overcharge Protection!!!
With NiCad Batteries if you overcharged them you would kill the life of the batteries.
And while all batteries do this LiIon are least tolerant. If you overcharge a LiIon battery, that is without Overcharge protection, the LiIon Battery with BURST INTO FLAMES! Thus the problem with the Sony Batteries that caused all those Laptop battery recalls.
gqstatus0685 said:
You are charging your battery too much thus killing it's battery life.
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Thats total BS with lithium batteries.
To the OP: Try running down your battery completely once, until the phone switches off by itself, then recharge fully. If you never do it and always recharge before the battery is empty the battery's power meter can lose its calibration over time and display weird things.
If it doesn't help, and you can notice a drop in overall life time you might need a new battery.
I have the exact same "problem" with my Tytn II.
Is slows down evenly though. (So the first 5 % of battery vanishes in minutes basically while the last 5 % can last for an hour, when it's half full % will last somehwere in between these two extremes).
Personally I've just interpreted this as poor measuring done by the hardware and/or software. (Ie I don't think the battery performs better the less full it gets as the meter in Windows would have me think)
kilrah said:
Thats total BS with lithium batteries.
To the OP: Try running down your battery completely once, until the phone switches off by itself, then recharge fully. If you never do it and always recharge before the battery is empty the battery's power meter can lose its calibration over time and display weird things.
If it doesn't help, and you can notice a drop in overall life time you might need a new battery.[/QUOTE
thanks ill try it out as soon as i get a chance...
kp
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may seem a daft point but after draining the battery, dont charge with the phone turned back on. gives a fuller charge cos its not being used and makes it quicker to charge, lol
duke0102 said:
may seem a daft point but after draining the battery, dont charge with the phone turned back on. gives a fuller charge cos its not being used and makes it quicker to charge, lol
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Click to collapse
Hmm...I don't see how turning my phone off to charge would increase the charging rate dramatically. My phone in standby mode uses 1% every 2 hours.
depends highly on roms and especially on radios.
with a crappy rom, battery could drop as fast as 10% per hour.
with a decent rom, battery drops in standby mode at a rate about 2% per hour.
duke0102 said:
may seem a daft point but after draining the battery, dont charge with the phone turned back on. gives a fuller charge cos its not being used and makes it quicker to charge, lol
Click to expand...
Click to collapse
If the phone is on but on standby that barely changes a thing. If it's on, with display illuminated then yes it might take you an extra 20 minutes to charge.. no big deal either.
*UPDATE*
ok so i drained my battery last night completely(turned on navizon, tt7, and skyfire) which took me about at most 2 hours.
Put it in for a charge
woke up at 9 and checked to see and it was 100%
I have push mail set to update every hour and i also run pocket sportscenter autoupdates which updates every 10 to 15 minutes
I used the phone for 5 minutes of calls
5 minutes of web surfing
a few text messages
and the occasional time check
at 6:30 pm battery life was at an amazing 90%
i was thrilled.
i continued to surf the web heavily from 730 to 8
a few more text messages
at 9 battery was at 67%
so i gotta believe that draining the battery helped recalibrate it...
i guess every 2 or 3 months i got to drain it out and give a full charge
thanks for the help guys
really appreciate it

Consistently Incorrect Battery Percentage

Hey all,
I have had terrible misfortune in the realm of battery stats. Ever since CM7 (and maybe even before) my phone is unable to figure out how much battery is left. Here is a common scenario:
Charge phone overnight, use phone throughout day, battery dies after 6-7 hours of moderate-heavy usage. I plug it in, reboot, and then it reports ~60% battery left.
Another common scenario is that it will dwindle around 5% battery or less and go up and down until it finally dies.
I know that this is a misreading of the battery and not battery drain or a rogue app because when I flash a new ROM the battery life is amazing for 1 day. The day after I flashed Team Hacksung's ICS rom, I got almost 17 hours of battery life with 2.75 hours of the display being on and 30 minutes of Google Music. I was blown away! But even then it was dwindling around 5% not knowing when it would actually run out. The day after, it was back to its old tricks of misreporting the battery percentage.
Today I charged it to 100%, unplugged it, and shut it off. Then I plugged it in while it was off and let it charge to 100% again and wiped battery stats in Clockwork mod. I'm getting ok-ish battery with that, but it's not even close to how good it was when I first flashed ICS.
Anyone have any ideas what I could try?
Thanks!
When you wiped the battery stats did you let the battery fully discharge and shut off before charging again?
After wiping battery stats it is recommended to let the phone fully discharge to the point where it will automatically shut off.
Keep in mind with the age of our phones, it could just mean your battery is dying. Try the above method, but in my experience uncalibrated battery only last a few days. The phone will "fix" it by itself the longer you use it.
j.curtis.369 said:
When you wiped the battery stats did you let the battery fully discharge and shut off before charging again?
After wiping battery stats it is recommended to let the phone fully discharge to the point where it will automatically shut off.
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Click to collapse
That's what I'm doing currently. Battery life seems improved, but we'll see what happens. It's nearing death now, ~6%. At this point it will probably misreport it for a few hours until it finally dies. I left it unplugged overnight, so now it's at 19.5 hours uptime with 1.75 hours display time.
Definitely improving! I hope that it successfully recalibrates.
Battery stats have nothing to do with how the os calculates remaining battery...they are what is displayed in settings>about phone> battery use and are reset each time you charge to full.
You're just giving it a good bump charge...wiping the stats is just a placebo effect.
studacris said:
Battery stats have nothing to do with how the os calculates remaining battery...they are what is displayed in settings>about phone> battery use and are reset each time you charge to full.
You're just giving it a good bump charge...wiping the stats is just a placebo effect.
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Click to collapse
Seriously? Wow I didn't know that. Is there a way to actually reset how the OS calculates the battery?
Does this app do anything?
https://market.android.com/details?...xLDEsImNvbS5uZW1hLmJhdHRlcnljYWxpYnJhdGlvbiJd
Nope...that app is just perpetuating the myth of what the batterystats.bin file does.
Don't hate me for this but, Then how come Roms usually give me better battery life after a full cycle? not bump charging or deleting battery.bin just running it?
Because the system for tracking the remaining power is getting to know your battery. once it gets a feel for it, it's more accurate. In theory anyway
So the "give it a day" is still true, at least in theory?
Sure
10 char
battery gauge temporarily fixed by removal and replacement of battery
Ever since I rooted my phone, I've noticed that the battery gauge/meter is way off. I keep an eye on the charging voltage and try to pull the plug around 3.92 volts. Problem is, the gauge is always reading low until I pull the battery, wait a few minutes, and then reinsert and boot up. Then it's fine for a while, but I notice it creeping down even though I keep topping it off with a charge to keep it around 3.92 volts.
What's going on? Do I have to fully deplete the battery and charge to full to have an accurate (or somewhat accurate) battery gauge? Do I have a bad battery (this battery has been used only a couple months)? Is something else going on here? Recommendations, studacris? Doesn't the os use battery voltage to calculate state of charge (%)?

Time for new battery?

Hey guys, I have a weird issue. Regardless what ROM I am on, my battery percentage will randomly drop like 10%
Randomly, I will be using it, I'll be at 70%, then it will just drop to 60%, normal use. Been happening a lot more recently.
Is this a sign of a battery going bad? I've had this phone roughly a year (Stock battery).
Thanks!
What does your battery life look like? A battery's performance WILL degrade over time, but if your battery life is still good enough for you, I don't see any harm in continuing to use it.
You could get an app like Battery Monitor Widget. It will keep track of usage and calculate the health of the battery. You can also try wiping battery stats (the app can do that too), it could just be the phone mis-reading the battery...

Inaccurate battery %??

After charging my battery fully to 100%, I unplug it from the charger and without even turning the screen on, the battery drains to 92% within one hour. I check the battery stats and there are maybe only a couple wakes during this time.
Sometimes, the battery shows a certain percentage longer than others. Example, my phone will be on 65% longer than it would be on 60%.
Battery still gives me a solid 2 days usage with about 3+ hours screen on time. The service menu also says that the battery is good.
Is there a way to get the battery reading to show more accurately?
Thanks,
Hope I could Help You
For your battery problem, I guess you could try calibrating it. And also try to install "Greenify" along with "Clean Master or 360 Security" and try to close all running apps before turning off the screen. I also turn on Stamina Mode when the battery is at 100%, in an attempt to further save battery life. And the result has been kinda meh, but well, battery drains about 1% per hour. It lasts about a day and half with light usage. In my case, light usage being, browsing, youtube videos for about 2 hours, listening to music, social networking and taking some pictures
Squatrack Curler said:
After charging my battery fully to 100%, I unplug it from the charger and without even turning the screen on, the battery drains to 92% within one hour. I check the battery stats and there are maybe only a couple wakes during this time.
Sometimes, the battery shows a certain percentage longer than others. Example, my phone will be on 65% longer than it would be on 60%.
Battery still gives me a solid 2 days usage with about 3+ hours screen on time. The service menu also says that the battery is good.
Is there a way to get the battery reading to show more accurately?
Thanks,
Click to expand...
Click to collapse
jeseunpark said:
For your battery problem, I guess you could try calibrating it. And also try to install "Greenify" along with "Clean Master or 360 Security" and try to close all running apps before turning off the screen. I also turn on Stamina Mode when the battery is at 100%, in an attempt to further save battery life. And the result has been kinda meh, but well, battery drains about 1% per hour. It lasts about a day and half with light usage. In my case, light usage being, browsing, youtube videos for about 2 hours, listening to music, social networking and taking some pictures
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Click to collapse
Hey,
im using greenify (my phone is rooted). Battery is quite good for me though. I get about 3 days with light usage. I start charging my phone again when the battery gets to anywhere between 10-20%.
I read that maybe its better not to let it get so low?
I have no wake locks either.
Umm.. IMO, 10-20% is okay. I usually charge the phone when the battery gets around 5%. I read somewhere that charging battery too early can affect the battery's overall standby time (reducing it). It's better not to let the battery reach 0% though.
I had that happen with my Samsung Galaxy Note 2 earlier. I once let the battery dip all the way to 0% many times. After a few charge cycles, I found out that the battery was dead and wouldn't charge at all so I ended up buying a new battery :-/
Umm.. Coming back to our Z1's, could you try putting the phone in stamina mode everytime the phone is kept on standby mode? This boosted my battery life a lot I even put my phone on stamina mode throughout the whole night yesterday to test the battery life again, and when I switched on in the morning, I saw that the battery had dipped by just 2% (standby time of 7 hours). I'm really confused how your battery drops so fast, 100% to 92%.
Could you try calibrating the battery and then putting it in Stamina Mode while on Stanby and tell me the results? I hope I could help :fingers-crossed:
Squatrack Curler said:
Hey,
im using greenify (my phone is rooted). Battery is quite good for me though. I get about 3 days with light usage. I start charging my phone again when the battery gets to anywhere between 10-20%.
I read that maybe its better not to let it get so low?
I have no wake locks either.
Click to expand...
Click to collapse
jeseunpark said:
Umm.. IMO, 10-20% is okay. I usually charge the phone when the battery gets around 5%. I read somewhere that charging battery too early can affect the battery's overall standby time (reducing it). It's better not to let the battery reach 0% though.
I had that happen with my Samsung Galaxy Note 2 earlier. I once let the battery dip all the way to 0% many times. After a few charge cycles, I found out that the battery was dead and wouldn't charge at all so I ended up buying a new battery :-/
Umm.. Coming back to our Z1's, could you try putting the phone in stamina mode everytime the phone is kept on standby mode? This boosted my battery life a lot I even put my phone on stamina mode throughout the whole night yesterday to test the battery life again, and when I switched on in the morning, I saw that the battery had dipped by just 2% (standby time of 7 hours). I'm really confused how your battery drops so fast, 100% to 92%.
Could you try calibrating the battery and then putting it in Stamina Mode while on Stanby and tell me the results? I hope I could help :fingers-crossed:
Click to expand...
Click to collapse
Yeah i could try to calibrate it. Im a little confused on what you do to calibrate the battery (ive read way to many opinions on this). Can you please tell me the steps.
Squatrack Curler said:
Hey,
im using greenify (my phone is rooted). Battery is quite good for me though. I get about 3 days with light usage. I start charging my phone again when the battery gets to anywhere between 10-20%.
I read that maybe its better not to let it get so low?
I have no wake locks either.
Click to expand...
Click to collapse
Squatrack Curler said:
Yeah i could try to calibrate it. Im a little confused on what you do to calibrate the battery (ive read way to many opinions on this). Can you please tell me the steps.
Click to expand...
Click to collapse
I used this to help me - http://forum.xda-developers.com/showthread.php?t=1024867

Android System Heavy Battery Drain

I bought the phone yesterday. When I charged fully overnight and unplugged this morning around 7:30, it drained %10 of my juice and it's now 11:08. It means 2.85% drainage for 1 hour. I think that's a little huge drain and when I look in to what's draining, it shows up to be Android system. I don't know how you guys get that tremendius battery lives but it clearly seems, I can't get it now.
Oh when I look at the cpu usage, it seems it can go to deep sleep too.
Will it fix itself in a few days? What do you think?

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