yashsingh1/xdaforums huggingface dataset:
[Nexus 7 Q&A, Help & Troubleshooting] dottat:
Re: [Q] My Nexus 7 is very slow to charge

So I'm on cm10 and just ran into this issue. Seems when the issue occurs, battery widget shows USB charging. If I unplug the charger brick for ten seconds and flip polarity then plug the USB cable back in I get ac charging and fast charging at that. Let me know if you can duplicate that.
[Nexus 7 Q&A, Help & Troubleshooting] nhutquang972012:
It just happens when I use PA 2.99 but now with CM10.1, it shows AC charging but still slow (as I said 4% to 32% in 8 hours). Now it's charging via PC, slow but the weird is that it's faster than wall charger !!!!!
[Nexus 7 Q&A, Help & Troubleshooting] Deleted member 4526420:
Re: [Q] My Nexus 7 is very slow to charge

We practically have the same problem. It's very annoying because it's more charging than more using. It destroys the user experience.

I noticed that sometimes it charges fast but most of the time, it's freaking slow...
[Nexus 7 Q&A, Help & Troubleshooting] TheGingerSage:
Re: [Q] My Nexus 7 is very slow to charge

It is because those ROMs don't have the fastcharge kernel and feature

Sent Via Nexus 7
[Nexus 7 Q&A, Help & Troubleshooting] najaboy:
Re: [Q] My Nexus 7 is very slow to charge

Fastcharge is irrelevant when connected to ac power.
[Nexus 7 Q&A, Help & Troubleshooting] TopGear63z:
I have the exact same issue, whatever i try my Nexus 7 takes sometimes 20 hours for a full charge. This is very annoying as my Nexus 7 consumes a lot of battery when using it, even when its connected to a charger. Im desperately looking for a solution, but i cant find any solutions. Does someone maybe know how tot fix this issue as it really bothers me.(i have tried so many roms and kernels so im sure that that isnt the problem)

Thanks in advance
[Nexus 7 Q&A, Help & Troubleshooting] holmes6:
Only solution I have found is returning the device to asus. They RMA'd it back to me the same as I sent it the 1st time. 2nd time they sent me a different N7 which charged fast for a few weeks. Now I'm not able to charge properly again and really not in the mood for 3rd RMA :crying:.
[Nexus 7 Q&A, Help & Troubleshooting] bftb0:
@TopGear63z

How fast does it charge when the unit is completely turned off?

- Let it run down pretty far say < 30%;

- put it on 2A A/C Charger

- while (not_fully_charged) {

-- turn completely off (cold shutdown)

-- wait 30 minutes

-- boot it to observe the charge % level

}
[Nexus 7 Q&A, Help & Troubleshooting] Mockingbird:
Re: [Q] My Nexus 7 is very slow to charge

yea suuure..

Sent from my Nexus 7 while being Paranoid :).
[Nexus 7 Q&A, Help & Troubleshooting] nhutquang972012:
Re: [Q] My Nexus 7 is very slow to charge

2012, my mistake....
[Nexus 7 Q&A, Help & Troubleshooting] rigor789:
Slow charge

Hey guys,

I recently got my Nexus 7 32GB, and i got it without the stock charger (it was too expensive at that point), so i read about the amperage and stuff, but managed to charge it via my 3x power usb from my gigabyte mobo, was a little slow but i could say acceptable, it took around 10h to charge from 5% to 100%. The next day i got a 2A usb charger and it was still slow, haven't really watched the times for charging. So now 9 days since i got my Nexus, i started a series of tests to see the charging speeds and put this table together:

gyazo(DOT)com/7609c8a1c864cac604a875b59d77d584 - As I'm a new member on the forum it wont let me post url, sorry.

As you can see when the tablet is off it takes around 8,5 minutes to charge 1%, and the time varies based on the settings (wifi, sync, plane mode).

The best i can get is 4 minutes to charge 1% that means the battery would charge from 1% to 100% in around 6.6 hours (if my calculation is right). It seems to be a bit too much for it, based on some people saying 2-3 hours for a full charge. Other than that the 4 mins / 1% is rare and varies. One day i was charging it for 6 hours and it only charged up to 73%. Not really a big of a deal but i wonder if this is happening to everyone. I noticed that the battery drains really fast when gaming, lasts around 4 hours, is that normal? I searched and read few posts about it but wanted to share my table too. Thanks in advance!
[Nexus 7 Q&A, Help & Troubleshooting] Beefheart:
Mine has started doing this recently. I put it on charge last night before I went to bed on 17%, woke up 7 hours later to find it on 58%. Ridiculous. It seems to have coincided with 4.2.2 roms as I don't recall it being like this on the old 4.2.1 roms.
[Nexus 7 Q&A, Help & Troubleshooting] jimbobvfr400:
I'm not saying it's definitely not software but I had a similar thing with mine and slow charging. I popped the back off and discovered the lead from the battery wasn't quite seated properly, it was just a little bit wonky.

unplugging and replacing the lead properly sorted me out. Just a thought.
[Nexus 7 Q&A, Help & Troubleshooting] dyepnoodle:
This **** happened to me. Ive been tryimg to charge this stupid tab for 2days now i cant get pass 31% did everything, charged it powered off/on, removed the back cover, checked the battery lead and still nothing tomorow will be the 3rd day of charging non stop and still 30% hate this!!
[Nexus 7 Q&A, Help & Troubleshooting] bftb0:
When you say "checked" do you mean "unplugged the battery lead and replugged it"?

The data sheet for the TI BQ72451 charge controller (the chip that charges the battery and also produces the "% charge" value) is stateful.

That might be why some people report that unplugging the battery lead and then re-plugging it cures some problems - presumably that chip is running 100% of the time as long as there is sufficient cell voltage (even when the tablet is "off"), so disconnecting it causes it to move through a different state sequence.

Not saying this is any guarantee of a fix for you, but if you give it a try, leave it unplugged for a while (minutes).

good luck.
[Nexus 7 Q&A, Help & Troubleshooting] Beefheart:
OK, following my last post above I reverted to the 4.2.1 stock backup I made before flashing my first custom rom back before Christmas when I bought the tablet. And guess what? The issue was nowhere to be seen and my Nexus charged from 41% to over 90% in a couple of hours. Quite a contrast to the 50-60% charge I was getting in 7-8 hours previously. As a result I have flashed the best AOKP 4.2.1 rom I could find, which is Omega 1.1 (http://xdaforums.com/showthread.php?t=2107054). And again, there is no charge issue that I can see and the tablet appears to be charging normally.

Given that I had this problem on all the 4.2.2 roms I tried (at least 3 of them) and it's now gone on two separate 4.2.1 roms, I would suggest people follow suit until Google rectify this issue with the next update.
[Nexus 7 Q&A, Help & Troubleshooting] bftb0:
Well, plenty of people don't have any problems at all with 4.2.x. But who knows, perhaps there are issues relating to the older hardware revisions of the N7.

My (grouper) N7 tablet charges from ~5% to 100% in a little over 2.5 hours when it is on (but sleeping). Same thing on both 4.2.1 and 4.2.2. But it is a newer build - Dec 2012.

It is hard to make heads or tails of these anomalous battery charging reports, as it seems that a bunch of important details are almost always left out. (Never mind that the installed apps can completely change the load behavior.)

- charger make and model

- build date/purchase date of tablet or hardware version identifier

- does the kernel log show a DCP, CDP, or SDP "cable detect" when the device is plugged in?

- use of custom kernel?

Here's an excerpt from /proc/kmsg at the moment of (OEM 2A) charger plug-in (note DCP):

<6>[21132.862490] tegra-otg tegra-otg: SUSPEND --> PERIPHERAL
<6>[21132.863017] fsl_vbus_session(): vbus_active = 0 and is_active = 1
<6>[21133.436660] INOK=L
<5>[21133.437231] smb347_charger: [cable_type_detect] Reg39 : 0x10
<5>[21133.437942] smb347_charger: [cable_type_detect] Reg3F : 0x83
<5>[21133.438207] smb347_charger: [cable_type_detect] USB_IN
<5>[21133.438912] smb347_charger: [cable_type_detect] Reg3E : 0x0a
<6>[21133.439172] [b][color=green]Cable: DCP[/color][/b]
<4>[21133.439425] ========================================================
<4>[21133.439890] battery_callback usb_cable_state = 3
<4>[21133.440142] ========================================================
<4>[21133.440607] battery_callback cable_wake_lock 5 sec...
<4>[21133.440617]
<6>[21133.444154] elan-ktf3k 1-0010: Update power source to 1
<5>[21133.448269] bq27541_get_capacity = 97% ret= 96
<5>[21133.449522] bq27541_get_psp voltage_now= 4109000 uV
<5>[21133.450891] bq27541_get_psp temperature= 250 (0.1¢XC)
<5>[21133.452042] bq27541_get_psp status: Charging ret= 0x0281
<6>[21133.866644] cable_detection_work_handler(): vbus_active = 0 and is_active = 1
<6>[21133.867081] AC adapter connect
<6>[21133.867640] elan-ktf3k 1-0010: Update power source to 1
[Nexus 7 Q&A, Help & Troubleshooting] lewmur:
I just bought my N7 and immediately upgraded to 4.2.2. From 50% charge with Asus charger, I only got an addtion 15% after charging for 75 minutes with the tablet off.

I also have have an HP TP with a two amp charger so I tried it. About the same charge rate. Tried the Asus charger on the TP, and it charges normally. So there is either an internal problem with the N7 charging hardware, or there is a firmware problem.

I'm currently downloading a 4.2.1 ROM and will see if it solves the problem. If that doesn't fix it, I'm going back to the TP. Battery life and charging time are much more important to me than blazing speed.
[Nexus 7 Q&A, Help & Troubleshooting] bftb0:
That certainly does not seem very good (mine charges at 3x that rate). But given that the tablet was off, it seems hard to believe that the result you got depends on the OS software - which was not running in that particular circumstance.

What does Asus/Google say you should expect? (I would bet that Asus sources batteries from at least two suppliers, if not more)
[Nexus 7 Q&A, Help & Troubleshooting] blissville:
I noticed this problem the moment I upgraded from 4.2.2 to 4.3. While charging and am using my tablet, it will be discharging. When the battery is completely drained and I plug in my charger, it wouldn't charge immediately, it wouldn't wake up until after say 10 - 15 minutes before it indicates charging. At this point of I try to put it on, it goes of immediately. I believe this is got to do with the newer versions of android from 4.3 to date. Right now am running kitkat and its not getting any better.I really thought it was my battery.
[Nexus 7 Q&A, Help & Troubleshooting] Momogs:
Reactivate battery

My Nexus 7 (2012) was experiencing the same slow charging issue. Went from 66% to 67% in 4 hours. Then I remembered when I lent my old Galaxy S2 to my brother and the battery wouldn't keep its charge. He took it out of the phone and gave it a couple hard whacks. Presto, the battery started behaving properly. I've given my Nexus 7 to my daughter, but the charging issue has rendered it almost useless. So I thought WTF and gave it two hard smacks on the lower back side. It immediately started charging properly, and was fully charged within an hour. Do it at your own risk, but it worked for me.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Or rather, don't.

Take it apart and replace the USB connector part, it costs what, $10?

Or take it to a repair shop and it'll be done for you.
[Nexus 7 Q&A, Help & Troubleshooting] Yscman:
Image

Hey man, can you upload the images again? I want to do that with my nexus 7 but without the image i don't have the courage to do it!

Can you help me please?

Thanks
[Nexus 7 Q&A, Help & Troubleshooting] MrFastZombie:
$20 right now, but when I had to replace mine, it was $50.

$50 for the 2013 model right now.
[Nexus 7 Q&A, Help & Troubleshooting] stoatwblr:
Really? My N7 will ONLY charge at 450mA (measured externally) no matter what the power source is, even when it says it's connected to AC.

I'd be a very happy bunny if it could draw 1A, let alone 2 - it wouldn't go flat on me even when plugged into the charger if it took an extra 300mA and it'd charge in a reasonable period if it took an extra 250mA over that.
[Nexus 7 Q&A, Help & Troubleshooting] Sorraia3:
I am having the same issue now and have tried the same troubleshooting, even replacing the battery and the charging port flex cable assembly. I'd like to give this a try since I am also out of warranty. Could you please repost the picture? It is no longer showing. Thanks! :)
[Nexus 7 Q&A, Help & Troubleshooting] germanmarky:
I don't specifically recall where I found the information (may have been this thread), but my Nexus 7 2012 would take forever to charge, and also after it was pulled from the charger would die very quickly. It would also LOSE charge while plugged in if in use.

The information that I found was to instead use the ASUS Nexus 7 Dock (already had one) to completely charge the tablet. Right now, it has been mostly idle with screen off for 2.5 hours, and it is still at 100%.
[Nexus 7 Q&A, Help & Troubleshooting] tremlar:
Hi, having a nightmare with my wifes Nexus and I obviously need to do this fix but your image isn't displaying is there any chance you could please re-post the image of where to solder. Really appreciated.
[Nexus 7 Q&A, Help & Troubleshooting] bloomer2011:
There might be a few different causes for similar phenomena, but for me it was an absolutely 100% software issue. After upgrading to KitKat (stock, not rooted), my N7 wifi 32GB would frequently (but not always) charge very very slowly. It appeared to happen almost exclusively when my alarm clock app was keeping the screen awake (faint clock on black background), with the battery charge dropping overnight, rather than improving. This had not been a problem (using the same app version) in JellyBean. If I checked afterwards what was consuming battery, it was always the glgps process (from comments online, people seem confused about what this does, and although it contains the letters "gps", it might instead stand for google play services). I couldn't find any way to kill/control this process successfully.

I upgraded to a Lollipop custom ROM and this was disastrous. The tablet would charge completely unpredictably, regardless of apps or screen on/off. The only reliable way to charge was to turn it off. The process glgps was no longer visible as the culprit (nor was any other process conspicuous).

I downgraded to a KitKat custom ROM (slimkat). For the first day or two, the charging problem still seemed to be present, but since then (three weeks now) the tablet has charged perfectly normally under all circumstances. I have no idea why the first day or two was different. Throughout the testing above, I used the same charger, cable and power outlet. Anyway, hope this additional input helps anyone else.
[Nexus 7 Q&A, Help & Troubleshooting] jfmcbrayer:
Did you have gapps on this ROM? If so, play services could well have still been the culprit. It seems like Lollipop obscures the process that's to blame for battery usage somewhat, relative to KitKat.
[Nexus 7 Q&A, Help & Troubleshooting] mr.crabs!:
Please, please reupload the image..!

If anybody has the image referred to in this post PLEASE reupload it. It could really help.

Thank you.
[Nexus 7 Q&A, Help & Troubleshooting] zelevw:
Try this, I worked wonders for me, I´m able to charge my N7 2012 in about 2 hours!

Since I´m not able to post URLs go to YouTube, search for "Slow Charging Fix for Nexus 7" video posted by ianmedina11 and try it...best regards.
[Nexus 7 Q&A, Help & Troubleshooting] mr.crabs!:
Thanks dude. Had a go at that one before. Seems more like it is treating the symptoms rather than the cause if you know what I mean. I can't help but feel it is a faulty component somewhere, probably a capacitor within the charge circuit (hence my interest in the original image of this post).

I have handled many nexus 7s and some have had this fault. My son's nexus is just beginning to show this issue.

I feel also that it could be due to the charge port itself, probably oxidation of the contacts (which I think would be helped by the repeated plugging/unplugging as shown in the above video until a good contact is made) or poor solder connections which may be fractured microscopically, reducing the flow of current. I guess rewetting the usb solder connections would help in this instance.

Also could be poor connection between the usb flex and the flex which runs under the battery to the main board. After that it is probably pcb component issue which I'm at a bit of a loss with.

I'm going to investigate my son's tablet and let you know what I find. This issue is annoying and let's see if we can't figure this one out together.
[Nexus 7 Q&A, Help & Troubleshooting] adeelraj:
which usb contacts u are trying to rewet plx post a pic here
[Nexus 7 Q&A, Help & Troubleshooting] mr.crabs!:
I am happy to report that my son's tablet is now charging just about as good as my own. I haven't had to play with the firmware/Kernel at all. It would seem that cleaning all the contact areas I have mentioned above has resolved the problem in my instance.

I did notice that it seemed to charge more as expected following a complete discharge followed by full charge.

I am going to see if my mother in law's nexus 7 can be sorted in the same way and let you know.
[Nexus 7 Q&A, Help & Troubleshooting] adeelraj:
Which part of ur nexus 7 u have cleaned plz tell me
[Nexus 7 Q&A, Help & Troubleshooting] sthpaw01:
Pics of what you cleaned please! I have a new battery arriving today. I haven't used my N7 in few months and it will not charge so I'm replacing the battery first. Knowing what I could clean inside the unit while im inside of it would help me out.
[Nexus 7 Q&A, Help & Troubleshooting] mr.crabs!:
If your nexus is not charging at all then I would first try leaving it on charge for an hour to see if it is just very drained. Check your charger works with another device. Check these things also:

》check your nexus is not in APX mode. You can check this by plugging it into your pc and checking under hardware devices under control panel on your pc to look for APX device. If it is, then your nexus is knackered and there is currently no fix (unless you have created 'blobs' for your device previously. This is a whole other topic which you can read about). All you can do now is replace the motherboard.

》check usb port is not damaged. This is the most likely probability. You can buy them quite cheaply now on ebay and they are quite easy to replace.

Sadly, I would be surprised if your battery is completely duff, just don't see that very often with these. If it does solve the problem then try putting your old battery back in and try charging it again for interests sake.

I will try and get some pictures posted for those who need some reference, but really it is quite self explanatory when you look inside your tab.

---------- Post added at 06:15 PM ---------- Previous post was at 06:14 PM ----------

Check my post above. All written there.
[Nexus 7 Q&A, Help & Troubleshooting] sthpaw01:
I did leave it on a working charger (because it charges other items) for a while but it never turned on. I will check out the rest of your suggestions when the battery arrives, thank you!
[Nexus 7 Q&A, Help & Troubleshooting] mr.crabs!:
Try it in your pc. In APX mode it won't appear to be charging. Plug it in, if nothing then press and hold power for 10 seconds or so to see if it is then recognised by your pc. Commonly APX mode occurs after a failed or interrupted system upgrade which has resulted in a borked bootloader.

Hopefully it is just because you have left it flat for a long time and sometimes the nexus will refuse to charge in this situation. In this case your new batt should sort it. There are other ways, but as you have a battery coming then you should be good.
[Nexus 7 Q&A, Help & Troubleshooting] sthpaw01:
I messaged you but you may have not seen it. I have replaced the battery and replaced the charging port and it still doesn't show any signs of power. I tried plugging into the computer and nothing happened.
[Nexus 7 Q&A, Help & Troubleshooting] adeelraj:
My problem solved with this cable

Charging back to 2.30 hours (0-100%) from 4-5 hours
[Nexus 7 Q&A, Help & Troubleshooting] mr.crabs!:
Happy to report two further tablets now charging at full speed again following cleaning of the parts mentioned in my post above.

I think a new cable will work for a while. It has brand new shiny contacts which will form a better contact with the pins in the micro USB of the charge port. Hopefully this will last, but for how long?

I am convinced that the slow charging is a problem of oxidation along the charging port/flex pathway to the battery. This I have proven three times in a row with three nexus 7's. All of which were taking at least 6 hours to charge and one of which was not always charging fully. They would always only draw 0.46A of current. Obviously they charged better with the device turned off as less battery power was needed and so charging could be more effective.

After cleaning they now draw 1.4A - a threefold increase. Now charging at between 20-30% per hour.

Need I say any more..?
[Nexus 7 Q&A, Help & Troubleshooting] adeelraj:
Can u plz post pictures of parts which u have cleaned
[Nexus 7 Q&A, Help & Troubleshooting] mr.crabs!:
Haven't really got time to do that now. If you read my post(s) above and crack open your nexus then all should become clear.

Regards,
[Nexus 7 Q&A, Help & Troubleshooting] adeelraj:
Post pics if u can

Other wise I am lost

Thnx BTW!
[Nexus 7 Q&A, Help & Troubleshooting] deepakgaba14:
I am facing the same problem and it would be great to have some pictures as I have not done this before.

Thank you.
[Nexus 7 Q&A, Help & Troubleshooting] DogzOfWar:
I am stealing these photos from other sites around the interwebs, but here's how I fixed my issues.

First, I used a combination of small flat-head screwdriver to pry open the case (no screws).

Next, I unplugged the battery like so:

[IMG="Removing the battery"]http://images.pcworld.com/images/article/2012/07/ifixitnexus7-3-11381076.jpg[/IMG]

Re-seating that black/yellow/red/white cable seemed to fix it a little bit. But not all of the way.

Next, I re-seated the USB connector.

[IMG="From Android Central"]http://i1113.photobucket.com/albums/k516/jcarter855v1/Tech%20and%20other%20kit/20150103_181642_zps0lyu84ou.jpg[/IMG]

There are 3 tiny screws that hold on that black bar, which is the speaker. It's fragile! Once you remove that black bar, I very gently pulled up some of the copper shielding, and was able to remove and reseat the USB connector (where those red arrows are).

After doing so, I was able to charge 30% in about 20 minutes (where typically it would add 5% per hour or some nonsense). It's amazingly better. I charge it using various cables from Monoprice, various charging adapters, etc.

(For reference, I'm running OmniRom, a 4.4.4 rom, which fixes the OS speed issues. It feels great to have my N7 back in good shape.
[Nexus 7 Q&A, Help & Troubleshooting] tinuthir:
You are a saint - this is literally the one thing that brought my N7 back from "won't charge beyond 1 percent and can barely run anything, even on A/C" to "charging like a boss". I applaud you! :)
[Nexus 7 Q&A, Help & Troubleshooting] Miro.J:
Thank you,

I had same issue, but now my N7 is charging normally again.

I don't have to buy new tablet.

:)
[Nexus 7 Q&A, Help & Troubleshooting] W10Geek:
Apparently I had a similar problem with the slow charging, so I changed the power brick. Instead of using the provided power brick, I used the Apple's 12W power brick. When using that, my Nexus 7 turns out to charge faster.

Note: It would fully charge in 4 hours.

Also, I found an Android 7 Nougat ROM (which I'm using) and makes my Nexus 7 really fast. I can't post a link of the ROM for some reason, so you'll have to google search it if you want the ROM.
[Nexus 7 Q&A, Help & Troubleshooting] happy-kat:
Used a guide and disconnected and reconnected the I/O port and battery, this has fixed my really poor battery charging (the current battery isn’t that old as had been changed), very pleased. charging has gone from 0.025 to a range between .81 to 1.29-1.31