yashsingh1/xdaforums huggingface dataset:
[Nexus 7 Q&A, Help & Troubleshooting] bsoplinger:
Much as I love my Apple products the way the company chooses to ignore existing standards and invent their own is frustrating. Relating to this thread this has lead to 2 standards for power supplies (chargers): the Apple standard and the USB standard defined in the USB 2 (and later) specifications. Originally the Nexus 7 used the USB spec of shorted data wires to decide if it should attempt to draw more than the spec 500ma a USB device is allowed to draw when connected to a computer. As of the update to Android 4.2 Google added smarts to the charging code in an effort to get the tablet to draw high power charging current from a charger using either standard. I'm convinced that this results in the tablet getting confused and chooses to only draw current at the lower 500ma rate. Perhaps the brand of cable results in electrical noise on the data lines which fools the tablet into thinking that there's a data connection. Regardless of what happens, plugging it into your computer will make a real data connection. Then moving to the charger will make a charge style connection and since it happens immediately after a real data connection the tablet has no problem deciding to shift to a high power current draw.

Sent from my Nexus 7 using Xparent Purple Tapatalk 2
[Nexus 7 Q&A, Help & Troubleshooting] jfmcbrayer:
That's an interesting theory, bsoplinger. If true, it might explain why my tablet slow-charges on lots of chargers that claim to be 2.1A. On the other hand, I'd like to see your references for this [Citation required]. There's a lot of hearsay and speculation going around about this issue, and I'd like to keep the evidence straight.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
If there was evidence, it would have been posted way back in December.

All we have is speculation, and yours, dear sir [MENTION=3514861]bsoplinger[/MENTION] , is the best theory we've had in a while.

It might explain things, given that I haven't connected my grouper to a PC in months...
[Nexus 7 Q&A, Help & Troubleshooting] bsoplinger:
You can see the description of the changes to the Android kernel for 4.2 in Google's code and find references to that particular change in discussions about the kernel. I know CM 10.something initially had issues with their kernel because it was based off 4.1 and not 4.2 source. You can find those discussions easily enough.

You can see the results of the kernel change in the charging behavior and how it takes a few minutes to decide to draw full charge current which is unlike its 4.1 behavior.

The reason that the cable makes a difference is pure speculation on my part. It's just an attempt to match the behavior described by different people with generally known facts about electrical current and cables and the knowledge that the kernel now attempts to determine if it has a data or a charge connection.

Sent from my Nexus 7 using Xparent Purple Tapatalk 2
[Nexus 7 Q&A, Help & Troubleshooting] Nate2:
My Nexus 7 is on Android 4.1.2.

I did not "upgrade" to 4.2.x, so all numbers posted by me in this thread pertain to the operation of the N7 on the 4.1 kernel.

FYI.

---------- Post added at 07:05 AM ---------- Previous post was at 06:58 AM ----------

It is an option you can turn on in this app: https://play.google.com/store/apps/details?id=ccc71.bmw
[Nexus 7 Q&A, Help & Troubleshooting] bsoplinger:
The Pro (paid) version of that widget can be configured to run without an actual widget and post the info shown 1 line per update in the notification area. I find it easier than looking at the stats info. Also makes it easy to see if my tablet was charging when docked. (That issue disappeared with new cable and charger.)

Sent from my Nexus 7 using Xparent Purple Tapatalk 2
[Nexus 7 Q&A, Help & Troubleshooting] jfmcbrayer:
That's pretty damaging to the latest theory then.

I can verify that for me, the procedure posted above (charge on USB, then switch to charger) does not work. But then, I've become convinced my stock charger is damaged, so my test may not really be applicable..
[Nexus 7 Q&A, Help & Troubleshooting] jfmcbrayer:
On the other hand, at one point today, my N7 got confused and was treating my trusty Archos charger as USB. The shuffle mentioned above did end the confusion.
[Nexus 7 Q&A, Help & Troubleshooting] crip:
Awesomeness can't believe that easy flipped charger you fookn rox..
[Nexus 7 Q&A, Help & Troubleshooting] jfmcbrayer:
For what it's worth, I bought an HP Touchpad charger off of FleaBay, and with the Monoprice cable, it charges around 1400 mA (as shown by CurrentWidget, which seems to show net current (charging minus usage)) as compared to around 800 mA for the Archos charger, and < 200 mA for my -- apparently broken -- stock charger.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Well I've narrowed my issue down to the tablet itself. Tried many power outlets (in 3 apartments, in 3 countries, at least 10 in each apartment -- at least one of these would not be broken), many chargers, many cables.

But the thing always receives less than the charger outputs. A lot less... (Also tried with a phone charger -- input is 200 mA at best)

Seeing as the mA the tablet gets tops out at 700 (if I'm lucky, usually less than 450), I'm beginning to wonder what's wrong. Pulling the battery is only a temporary solution, as it only helps for mere seconds. Restarting doesn't help either, nor does charging when the tablet is off. Also tried the 'connect-to-PC-via-USB-and-then-plug-it-in-a-charger' trick, but no luck...

Estimated charge time from 0 to 100% is around 10 hours, that's 10%/hour. If I'm lucky enough to get 700mA from the charger, it takes around 7-8 hours.

Now what in the world could be causing this?

I see we don't all have the same issues -- some have broken chargers, cables, some have broken kernels. Maybe we all have different hardware versions? Mine is a er3, or so I think. Will check again, as I'm not sure...

I'll download the official 4.1 ROM once I get home from vacation (the Wi-Fi is so bad, I'll be lucky if xda servers even get this message :P). Just to see if it's really kernel -- or any software for that matter -- related.

Or maybe I just have so much sh*t on the poor thing...?

Anyways, will get back with results hopefully this Sunday. Am always alert, watching this thread in case somebody gets any idea what all this could be. :D

Cheers from Croatia! C:
[Nexus 7 Q&A, Help & Troubleshooting] einjelhart:
charging

how come you can use the vise versa charging for your nexus, if you can check the end of usb cable is not same cut. you mean if im going to plugged the cable to my nexus port vise versa this will work. anyway i just replaced the original usb cable by other brand logitech and plugged it to my nexus it charges faster now than the original usb cable. i wanna try your tricks by doing other way of inserting the cable but i'm afraid because of the polarity or the right way to use this usb cable.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
No, no, no. You don't flip or turn the cable. You turn the charger itself.

Now imagine your charger being this letter: h.

The USB port is on the top, the forks that go in the wall are on the bottom.

You take it out if the power outlet and rotate it 180° in this direction: -->

Oh, yeah, and that also didn't work for me (on more than thirty outlets).
[Nexus 7 Q&A, Help & Troubleshooting] kentfor:
New charher

For what it's worth ... after months of dinking around ... a brand new OEM charger from Amazon had me back to normal duration charges immediately.

Crazy to have to replace a charge so soon? Yes.

Worth it to end my frustration? Yes.
[Nexus 7 Q&A, Help & Troubleshooting] jastonas:
Any news?

I sent mine to asus service. When it got back, it worked for a couple of days, then it got worse. I've sent it back again...
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Yup, a lot of news.

Installed a factory image 4.1.2. The battery didn't seem to get any better (a calibration issue maybe?), but then I got the notification whether or not to update to JDQ39. What the heck, I said, and now things seem to be getting a lot better.

I get at least 1200 mA out of the charger, and that translates roughly to at most three hours and a half of charging. That's 3.5 hours, mind you.

I think I'll do a calibration, see if it helps. Though I'm sorry I never did one on 4.1...

The question remains, though, what was the matter? Obviously it wasn't the kernel, maybe it was overloaded with my installed apps? Or my kernel wasn't quite as good as I was lead to believe? Weird, but all's well that ends well, I guess. IF this is the end, of course... :P

I just did all of the flashing at 3 in the morning, so please understand the delay (I literally just woke up). Now it's 9:21, CET. :P
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Okay, an update!

After some time with my pure AOSP-ish Nakasi on build JDQ39, I can positively say that wiping EVERYTHING that you have on the device does not help. (I thought installing a factory image doesn't touch the SDcard. Oh no, my game progress! ;-;)

I've tried finding the Google support email, to really see what's up with all this, as it's obviously a hardware issue (unless both 4.1 and 4.2 are broken, which I doubt, but I do not exclude this option). If it is indeed a software issue, we can only pray that 4.3 brings the needed fixes. If it's a hardware bug, then, well... I just hope your warranty isn't out yet.

Good thing I still got mine. Just gotta lock the bootloader and everything's gonna be fine and dandy. (I paid an extra 30$ in the shop where I bought it so that no matter what happens, they'll fix it. For 3 years. Even if the entire screen is broken. Good deal, eh?)

Will be relocking, flashing a factory image, using it for a week, and then go have a talk with the shop people. Will report EXACTLY what they did to the tablet and I hope it works. (They might replace the USB port, some cables, chips, the entire board, or even replace the tablet in whole. I don't know how skilled these people are, so anything might happen.)

P.S.

Anyone got that Google support email? I'd like to have a word with them before I relock the BL...

Allt the best,

--someone755
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Even more news! After the completely legit OTA 4.3 update, I've come to notice a bit faster charging. First there was no charging (talking just 4.3 here), then there was the 12 hour charging and now it's normal.

Did a new factory image restore, the 4.1 one and got updates via ota. No root or any modifications, not even a recovery, just an unlocked bootloader.

Maybe it's just temporarily so, maybe El Goog actually fixed something...

I'm having a slight hunch that different hardware versions may be the cause of this. Mine is ER3, definitely, can ask you people post yours (in case you haven't bought the new nexus 7, that is)?

Thanks!
[Nexus 7 Q&A, Help & Troubleshooting] ianmedina:
guys i made a video on how to fix slow charging issue of your Nexus 7. i hope it helps.

http://www.youtube.com/watch?v=bZFcfirYvuA
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
You got a point there, maybe my cable has dirt on it (or the charger has dust inside)... Though I always do that for every charger before I put my device in, so...

Also, you say that the N7 is from 'twenty-thousand twelve'... No offence, just a heads up :P

(Tip: it's either two-thousand twelve or twenty-twelve)

Still got a like from me, though :D
[Nexus 7 Q&A, Help & Troubleshooting] ianmedina:
Lol. But i swear it's really working!
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Okay, this thing is actually working!

Though if I unplug the tablet and plug it back in 5 minutes later, the charger output drops to ~600-850 mA.

There are still questions to be asked and answered, but I'm way too noob to figure them out... :P

Semi-temporary solution, but I guess I'll live.
[Nexus 7 Q&A, Help & Troubleshooting] mrhomiec:
short story, ever since i manually flashed 4.3, i've had slow charge times.

long story, i've had this rooted for almost a year now, and just a few weeks ago, i unrooted to 4.2.2. even while i was still rooted, and the first few weeks of unroot, i did not have any slow charge issues. then a few days ago, i plugged it at about 10%-20% charge around 10pm, woke up at 5am and it was only up to 47%.

i followed a suggestion from this post- http://xdaforums.com/showpost.php?p=39107960&postcount=4

i tested a battery drain to 10%, powered off, then charged for 75 minutes. i powered on, and it only got to 27%.

i'm highly doubting it's the USB cable or wall charger, as i'm using the same cable and charger as i was before i installed 4.3. could it be because i manually flashed 4.3, and not an OTA? or not even sure that's an issue since it's not really charging very well when powered off.

and for the sake of argument, i have tried 1 additional cable, and 1 additional wall charger, both with slow results. not sure on the exact numbers tho.
[Nexus 7 Q&A, Help & Troubleshooting] ianmedina:
Try the video i posted here. It's actually working.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Yeah, did you try the thing [MENTION=4142668]ianmedina[/MENTION] pointed out?

Looks like the tablet won't take in enough miliamps unless it's pluged, unplugged, plugged and unplugged... Several times... Though that might and might not work.

Though, I'm having issues yet again. It worked, twice, but now, the tablet just charges constantly at about 260mA. There are some jump to 560, but rarely, and only for mere seconds. The numbers are always the same, they don't change, ever. (The numbers I wrote here aren't accurate, it's my brain talking, but it's roughly accurate)

The tablet sees the charging as AC, not USB.

So now, it needs over 16 hours for a full charge.

I've had enough, I'm taking mine to the store. Maybe I'll be lucky and they already have the new N7s, so they'll replace mine for a new model :D

Or I'm just too optimistic and I'll get the old model, complete with all the bugs. Or maybe they'll fix my current one, who knows!
[Nexus 7 Q&A, Help & Troubleshooting] pepperbreath:
I'm having a similar issue with a few differences. It'll detect that it's charging with AC or USB properly but won't charge at all with AC. Battery drains as normal. It'll charge a little bit with USB but only up to about 57% and then it starts draining again. Takes forever to charge via USB too.

Tried different cords, different chargers, and even different batteries but the issue remains. :(
[Nexus 7 Q&A, Help & Troubleshooting] bsoplinger:
This sounds exactly like what I was experiencing. My fix was a monoprice cable and HP touchpad charger from eBay. Now it consistently charges at 1.5A+ as soon as I drop it into the dock. The combo cost less than $20.

Sent from my Nexus 7 using Xparent Purple Tapatalk 2
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
[MENTION=3514861]bsoplinger[/MENTION]

Would be great if they sold these where I live. But they don't even sell HP tablets, what even chargers ;-;

Maybe it IS the charger that's broken. Though in that case, every charger I have would be broken... :I
[Nexus 7 Q&A, Help & Troubleshooting] mrhomiec:
Tried the video last night. Then with it off and at 10% again, I let it charge for 75 minutes. This time it got to 25%.

After that, I tried the video tip again, and let it charge over night while I slept. Woke after 7 hours and it was fully charged. This was a pleasant surprise. Going to test again when the battery gets down to 10% tho.

UPDATE:

so i tested the video method each time before charging. the first night (Sunday) i wasn't able to test powering off and charging for 75 minutes, but after 7 hours of it powered off and while i slept, i woke up to a fully charged battery coming from 10%.

but on the second night (Monday, yesterday), i did test powering it off at 7%, charged for 75 minutes, and it only went up to 17%. then after 7 hours of it powered off, i woke up to it charged to 90%.

not sure what to do. i'm using the stock wall charger, it never gets unplugged. and a Monoprice USB cable that's never been unplugged until i started using that video method. i think it's more than just a coincidence that this all starts happening after 4.3 was installed.
[Nexus 7 Q&A, Help & Troubleshooting] pepperbreath:
Since my original threat (which is reply-less), I've tried a few more chargers, a few of which have a similar mA output to the HP Touchpad charger. Absolutely none of them worked.

The only thing that seems to charge my tablet is via USB. I even tried the trick in that video. No dice. :(
[Nexus 7 Q&A, Help & Troubleshooting] jfmcbrayer:
I've tried several chargers which purport to be 2.1A since my original charger died. Almost none of them charge at higher than 500mA. My wife's Archos 70A charger (purports to be 1.5mA) charges it at 800-1000mA; the HP Touchpad charger (purports to be 2A) I got from eBay charges it at 1000-1600mA.

Manually flashed 4.3, which made no difference (positive or negative) regarding charging.

My strong recommendation for people with slow charging is to first try their original ASUS charger with a Monoprice 28/24AWG ferrite-core cable or similar. If you're still getting slow charging, buy the Touchpad charger from an online source. It's only about $10 or so. Or you might try a new Nexus 7 charger from ASUS (but they're more expensive). Using CurrentWidget (which to get its data requires a feature in most custom kernels, but not the stock kernel) will help you quantify what you're getting from different chargers and take the guesswork out of whether a given charger is working.

---------- Post added at 10:11 AM ---------- Previous post was at 10:07 AM ----------

Honestly, I would not be surprised if every charger you have is broken (or lies about its capacity, or is somehow incompatible). You can find the touchpad charger on ebay or similar places -- the actual tablet isn't sold anymore (and was actually discontinued about a month after it was first released). There are surely other good chargers out there, but the HP Touchpad charger is cheap, and known to be good.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Ummm, is it just me or is CurrentWidget not supported on the Nexus 7?

Works on my phone, but Play Store says it's incompatible with the tablet...
[Nexus 7 Q&A, Help & Troubleshooting] jfmcbrayer:
Hmm. I installed it from the Play store, but now it's not showing up for me. You can install it from F-Droid if you can't install it from the Play store, but it doesn't work with the stock kernel.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
I don't understand, doesn't pa (android 4.2) come with a custom kernel?
[Nexus 7 Q&A, Help & Troubleshooting] bsoplinger:
The widget requires specific information from a file created by the kernel. Not all custom kernels create it and neither does the stock kernel.

Sent from my Nexus 7 using Xparent Purple Tapatalk 2
[Nexus 7 Q&A, Help & Troubleshooting] Lim Wee Huat:
Have anybody tried charging their N7 with a normal phone wall charger. I've tried charging with the stock charger and it's painfully slow but when with a 800ma phone charger, it's charging normally.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
I've tried that, but it only charges at 100-200mA...

I guess we don't all have the same issues...

EDIT: Alright, another experiment.

PAC (Android 4.2) and franco.Kernel.

The charging issue persists, and I'm really getting frustrated by this. Especially after getting Gangstar Vegas to work like it should (looks like all I needed to do to run the game at Normal was to overclock the GPU to 650MHz. So much for T3's 'advanced graphics'...).

Also tried different cables, including a Sony one (really high-quality). Only the first charge with it was successful, the others all gave me less than 400mA. Same with an HTC and a Nokia cable.

Wipes, Seeders, reflashes, kernels, different cables or charges, nothing helps.

Also, the tablet thinks it's in USB charging a lot of times.

Bump.
[Nexus 7 Q&A, Help & Troubleshooting] Scellow:
Same issue .. only happened when i charge it with PC

On device manager it say :

Power Requiered : 500 mA
[Nexus 7 Q&A, Help & Troubleshooting] najaboy:
Not quite sure I follow you. Slow charging via ausb port is expected behavior and is not a problem.
[Nexus 7 Q&A, Help & Troubleshooting] Usersname:
So this has just started happening for the past week or so and after reading the thread and my history with the tablet (since couple of months after launch) leads me to believe it is a hardware issue. Device is stock, problem started before I updated to the most recent version and continued afterwards. Since I owned the device I have used an HP Touchpad charger+cable, but for the past two months or so Ive used the HP charger and Nexus cable. I have had trouble charging before but it turned out to be the cable, once I swapped it out it worked and the bad cable wouldnt charge other items. Always used the same outlet and never cared about polarity, honestly that seems a bit silly.
[Nexus 7 Q&A, Help & Troubleshooting] someone755:
Well that all was enough for me.

Not only that it wouldn't charge in 3 hours, it neeed 12.

And then, it wouldn't connect to my PC for longer than 5 minutes.

I sent it back Friday, and told them to tell me everything they do with it (perhaps we can get a tip on what this may be).

If they can't fix it, I'll probably get a replacement with the same issue. -.-' (Or, since the 2012 models are out of stock, I might get a 2013 model as a replacement. :P)
[Nexus 7 Q&A, Help & Troubleshooting] Nate2:
The 2012 Nexus 7 is a non-monogamous/promiscuous device: it requires different chargers frequently to get the full 2A charging. Lol!

Notice how my original Asus charger and cable now takes 5 hours to charge from 14% to 100%. Could be worse..

2013/08/10|09:49:05 PM|0mA|14%|3740mV|31.1ºC|.0|1

2013/08/10|09:59:05 PM|656mA|17%|3793mV|31.5ºC|.15|1

2013/08/10|10:09:05 PM|808mA|20%|3808mV|31.7ºC|.0|1

2013/08/10|10:19:05 PM|776mA|23%|3822mV|31.9ºC|.0|1

2013/08/10|10:29:05 PM|1024mA|27%|3832mV|32.1ºC|.0|1

2013/08/10|10:39:05 PM|790mA|30%|3837mV|32.2ºC|.0|1

2013/08/10|10:49:05 PM|718mA|32%|3840mV|32.3ºC|.0|1

2013/08/10|10:59:05 PM|790mA|35%|3844mV|32.3ºC|.0|1

2013/08/10|11:09:05 PM|790mA|38%|3850mV|32.3ºC|.0|1

2013/08/10|11:19:05 PM|790mA|41%|3858mV|32.2ºC|.0|1

2013/08/10|11:29:05 PM|808mA|44%|3867mV|32.0ºC|.0|1

2013/08/10|11:39:05 PM|1078mA|48%|3882mV|31.8ºC|.0|1

2013/08/10|11:49:05 PM|790mA|51%|3892mV|31.7ºC|.0|1

2013/08/10|11:59:05 PM|754mA|54%|3907mV|31.5ºC|.0|1

2013/08/11|12:09:05 AM|808mA|57%|3926mV|31.3ºC|.0|1

2013/08/11|12:19:05 AM|1034mA|61%|3946mV|31.1ºC|.0|1

2013/08/11|12:29:05 AM|754mA|64%|3963mV|30.9ºC|.0|1

2013/08/11|12:39:05 AM|700mA|67%|3979mV|30.7ºC|.0|1

2013/08/11|12:49:05 AM|1024mA|70%|3991mV|30.5ºC|.0|1

2013/08/11|12:59:05 AM|733mA|73%|4008mV|30.4ºC|.0|1

2013/08/11|01:09:05 AM|690mA|76%|4026mV|30.2ºC|.0|1

2013/08/11|01:19:05 AM|647mA|78%|4041mV|30.1ºC|.0|1

2013/08/11|01:29:05 AM|808mA|82%|4060mV|30.0ºC|.0|1

2013/08/11|01:39:05 AM|862mA|85%|4077mV|29.9ºC|.0|1

2013/08/11|01:49:05 AM|646mA|88%|4106mV|29.7ºC|.0|1

2013/08/11|01:59:05 AM|647mA|90%|4130mV|29.5ºC|.0|1

2013/08/11|02:09:05 AM|646mA|93%|4150mV|29.4ºC|.0|1

2013/08/11|02:19:05 AM|647mA|95%|4168mV|29.3ºC|.0|1

2013/08/11|02:29:05 AM|581mA|97%|4180mV|29.0ºC|.0|1

2013/08/11|02:39:05 AM|431mA|99%|4188mV|28.7ºC|.0|1

2013/08/11|02:49:05 AM|272mA|100%|4194mV|28.4ºC|.0|1

But the battery did last 9 days (my record is 13 days on a single charge; atypical use, with it mostly sleeping), so I'm not complaining :)

I am on Android 4.1.2
[Nexus 7 Q&A, Help & Troubleshooting] lauvassirds:
Simply turn off your Nexus 7 and charge it then.
[Nexus 7 Q&A, Help & Troubleshooting] Usersname:
it still happens, read the thread