[Q][Solved]My Nexus 7 is very slow to charge

Solved! (at least for me)

I suspected this was hardware for a while since this issue would happen no matter what ROM was on there and no matter how many times I did a factory reset. Knowing that I'm just out of warranty and that Asus would probably charge me a hefty fee for fix it, I figured I had nothing to lose. Read my own thread on the issue to see what troubleshooting steps I had already tried here: http://xdaforums.com/showthread.php?t=2390222

Anyway, I took the back off and then removed the battery (the connection was fine btw). I removed the three screws that held the speakers in place. Then, suspecting that the small connections might need to be rewet, I plugged in my soldering iron and rewet the following areas in black (image borrowed from iAppleDev as I forgot to take my own) :



For insurance, I also folded up a small piece of paper and placed it where the blue box is. Screwing the speakers back in place held the paper in place and held the ribbon cable retainer clip against the connectors, giving a stronger connection.

I turned off my Nexus 7 with a 9% battery and then when to take care of other things. Came back in an hour or so (probably less) and I see that the battery is already at 33%! This is with the Asus charger plugged in, which wasn't working at all previously.

Very stoked. Kinda bummed I didn't figure this out before a conference I had to go to last week. Would have been nice to read on my Nexus 7 instead of my phone.

I have a little insight to share on this topic that might apply to some of you.

I bought mine back in december from costco and had no issues up until last night.

Up until then it had been sitting on its official charging dock by asus underneath my TV plugged to a big UPS along with my TV and amp.
Last night I decided to move it into my bedroom cause I wanted to start using it as a clock and to listen to music or podcasts before sleeping and to wake me up. Even before I got the dock the OEM charger was always done within 2.5 hours at most from a very low state like under 10% cause I was using the hell out of it back then.

I had to do 2 things in order for this to be practical for me.

1. The damn usb cable they give you is so short you couldn't hang a mouse with it so I changed it for one twice as long.

2. I plugged the OEM charger and dock to a APC Surge Arrest, Not a piece of crap power bar (or so I thought).

And here is what happened.
I went to bed with the battery at about 22% and when I woke 8 hours later the battery had only managed to get up to 57% which is unacceptable.

I then did 1 thing I unplugged it from the APC Surge Arrest (POS power bar that I might soon throw in the trash!) and straight to a wall outlet. I did not shut it off simply put it on sleep/standby instead of letting it be daydream clock.

Then I came here and read this thread, I at first had the suspicion that maybe it was the USB cable I switched but after reading somebody's comment about polarity I thought perhaps I was a tired last night and plugged it in the wrong way. It's pretty easy to do that actually and its still a possibility that it was plugged to the APC the wrong way.

After reading all the comments here and getting a coffee, Which maybe took me 10-15 minutes at most I went back to check on it.
At this point it was already at 60%. Then instead of putting it to sleep I just let it as I normally would on Daydream clock and by the time I finished typing this message it was at 65%. This fast charge is normal for the dock.

So problem is solved here it was the power brick that it was plugged to or possibly the polarity. I am going to know today if that is the case because I have a Nexus 10 charger that I also plugged into that same power bar last night so next time it needs a recharge I will keep an eye on its progress. If the Nexus 10 charges up fine then either the ASUS charger does not like the APC Surge Arrest or it was plugged the wrong way or the outlet on the APC that I used was bad or something and if its the latter that thing is still going into the trash.

For those plugged with the charger straight to the wall I would recommend the following.

A. Make sure its plugged in the right way or just reverse however its plugged in now.

B. Try another outlet and if that's also slow maybe have them tested with a tester or looked at by a electrician.

But if you are plugging them into some kind of power bar / surge protector then do try them directly to the wall and see if that helps.

90% of the homes I had lived in have had crap power installations, Way too many outlets on the same breaker or missing grounds so on which is why I always end up redoing them or installing separate outlets on their own breakers for my gear like my PC's and TV's.

Just my 2 cents. I went from terrible charging rates like those describes 3% per hour up to how it should be so hope this helps some of you.

Having to RMA my n7 would have been a real bummer. Especially if it would have been for nothing.

To add one last thing to my long winded post. Don't even bother trying to charge it via any kind of USB port on your computer its so slow you might as well have it on a hamster wheel with a dynamo. You really do need a real charger or the wait is unbearable.

Guys.... i have a friend from asus who told me that if you have slow charging problem you gotta do this.


use the stock asus usb cable
plug it in to your computer and make sure it's charging via USB, then just wait for 3 minutes then
unplug it, charge/plug it in via AC using stock asus 2A charger. then wait for atleast 5-8 mins
then check it if it's starts to charge quickly. =)

Hit thanks if it's working.

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

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