Nexus 7: extremely slow charging, any fixes?

zer0n1nja64

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So I bought a Nexus 7 at bestbuy about 3 weeks ago and it was charging incredibly slow, about 12 hours to full charge and not being used, no matter what combination of charger and cable I picked.

So I figured I got a bad one and returned it for another, and I have the exact same issue! Whether I use the charger, a computer, 3rd party wall plugs (2.1amps) or any combination of cables it just doesn't want to charge. I like the nexus 7 but when I can't really keep it charged, it's frustrating.
 
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zer0n1nja64

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Re: installed any apps employing "privacy rape" for profit?

Nothing is running, and I've only installed a couple apps like pandora and dropbox. None of which are running and the tablet charges at the same rate even when turned off. The battery lasts about 10-11 hours but the battery takes that long to fill as well.
 

Roffles

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Re: installed any apps employing "privacy rape" for profit?

If you have this problem with two devices, and you claim you don't have any junk apps sucking up your power, and you also claim to have used different combinations of chargers and chords, then it's your wall socket not delivering enough juice. That's the final logical conclusion because the N7 doesn't take 12 hours to recharge. Try recharging it at a coffee shop or your work to see if that makes a difference. If that still doesn't make a difference, then you have junk apps on your device you aren't talking about or don't know about. Maybe you are running bloatware, or a torrent client, that activates only when being charged. So disable wifi and charge to see if that makes a difference.

At home, using a samsung or motorola branded charger (don't remember which one), my nexus 7 charges at a rate of ~10-12% every 15 minutes. It charges very fast at home! At work, using the asus charger connected to a surge protector, it charges at ~10% every 20 minutes. My unit recharges noticeably faster at home. In my experience, the socket makes a difference.
 

Joe Joejoe

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Re: installed any apps employing "privacy rape" for profit?

mine charges pretty fast. I haven't timed it, but I'd say about 2 hours to full charge is pretty accurate. I just plugged it in 20 minutes ago and it went from about 72% to 86% battery. that's with the device on but the screen off.

I suppose a bad socket can cause slow charging, but sockets are pretty high powered on their own, so something would have to be severely impeding the flow of electricity in order for a socket to not be delivering enough juice. perhaps dusty inside the socket or the pins aren't making proper contact because of the contacts inside of a socket being messed up some how. in any case, chances are it's just that single socket affected.

when charging, if you feel the back of your device getting warm at all by the camera, something is definitely running and using power.
 

zer0n1nja64

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Re: extremely slow charging, any fixes?

Its basically stock, minus 2 apps I've tried out. Its been plugged into computers(fully capable of charging a retina iPad), wall outlets at work, home, everywhere. Its doing nothing while charging, just off and no activity. No apps running and even when I turn it off it charges at the same rate. If I use the nexus for basic web browsing, it doesn't charge but it doesn't drain either, its a perfect balance.
 

Joe Joejoe

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Re: extremely slow charging, any fixes?

if you've tried it everywhere and 2 different ones get the same results, there's really not much else to identify the cause. one thing is for sure, they should charge pretty rapidly.
 

bjrosen

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Re: extremely slow charging, any fixes?

Your problem is probably the cable, there are charging cables and data cables, you want to be using a charging cable from a wall charger. The USB ports on a computer deliver much less current than a wall charger as do data cables.
 

snoopyandroid

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Re: extremely slow charging, any fixes?

I have the same problem. My N7 takes forever to charge. Also, the plug gets VERY hot, so hot that I'm afraid to leave it plugged in over night for fear of something happening. However, I found the problem. Due to wall plug locations that is beyond my control, I have to charge my various devices via old power bars or extension cords (and in some cases BOTH!!!) and this is creating the slow charging and hot plug. I'm testing this theory at work with the N7 plugged directly into an outlet and the charger heat is normal and these are the numbers I've been achieving.

Power is on, screen is off and not using the N7

Started charging at 8:06am - 14%
8:17am - 20%
8:27am - 25%
8:35am - 30%
8:49am - 37%
9:00am - 43%
9:15am - 51%
9:46am - 65%
10:00am - 76%

You get the picture. Hope this helps.
 

markdek

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Re: extremely slow charging, any fixes?

The length of the cable, and the charger's rated amps, will affect the charge rate. Normally, it should be pretty fast.
 

YAYTech

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Re: extremely slow charging, any fixes?

Just a heads up, it will charge very slowly plugged into a computer's USB port, which doesn't put out as much amperage as a USB wall charger. From a quick google search, it looks like a computer USB port puts out .5a, as compared to the stock charger's (if I remember correctly) 1.35a.

I understand you've used other chargers, etc, I just wanted to point out that slow charging is to be expected in this particular setup.
 

jerrykur

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Re: extremely slow charging, any fixes?

I have the same problem. My N7 takes forever to charge. Also, the plug gets VERY hot, so hot that I'm afraid to leave it plugged in over night for fear of something happening. However, I found the problem. Due to wall plug locations that is beyond my control, I have to charge my various devices via old power bars or extension cords (and in some cases BOTH!!!) and this is creating the slow charging and hot plug. I'm testing this theory at work with the N7 plugged directly into an outlet and the charger heat is normal and these are the numbers I've been achieving.

Power is on, screen is off and not using the N7

Started charging at 8:06am - 14%
8:17am - 20%
8:27am - 25%
8:35am - 30%
8:49am - 37%
9:00am - 43%
9:15am - 51%
9:46am - 65%
10:00am - 76%

You get the picture. Hope this helps.

You should disconnect those power bars and extension cords. You are getting multiple power drops and each once is converting electricity to heat which could cause a fire.
 

snoopyandroid

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Re: extremely slow charging, any fixes?

You should disconnect those power bars and extension cords. You are getting multiple power drops and each once is converting electricity to heat which could cause a fire.

Two things:

1) Yes, I figured the multiple plugs (or one) was the issue, that's why I did my test at work.
2) Please re-read "Due to wall plug locations that is beyond my control"

FYI, I re-did the test last night at home plugged directly into the wall and all was good, regular heat and fast charge. So it looks like I'll have to plug into the wall to charge it over night.
 

masseurca

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Re: extremely slow charging, any fixes?

You will have issues if not using the charger and cable that came with the Nexus, just FYI. Anything else isn't supported.

Sent from my Nexus 7 using AC Forums mobile app
 

carbon fibre

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Re: extremely slow charging, any fixes?

So I bought a Nexus 7 at bestbuy about 3 weeks ago and it was charging incredibly slow, about 12 hours to full charge and not being used, no matter what combination of charger and cable I picked.

So I figured I got a bad one and returned it for another, and I have the exact same issue! Whether I use the charger, a computer, 3rd party wall plugs (2.1amps) or any combination of cables it just doesn't want to charge. I like the nexus 7 but when I can't really keep it charged, it's frustrating.

Anandtech did a... thorough review including checking charge time.

3.6 hours. 12 hours is not normal.
 

DeviceNode

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Re: extremely slow charging, any fixes?

FYI, I'm an electrical engineer and I design, build and test LiIon charging circuits (among other things) so I know a bit about this topic.

I see a number of half-truths and myths about electricity and charging in this thread. The Nexus-7 specific information was true, that it should take 3.6 hrs, not 12 hrs, and any significant applications running can extend the charging time. Certain chargers and cables may extend charging time, more on this below.

The Myths:

1. No amount of extension cords or power strips or surge protectors on the A/C side of things can possibly affect charging. USA power is maintained between 110 and 125VAC. You might get a few fractions of a volt or a few volts drop over extension cords IF you have something like a space heater running at the far end of the cords where you plug in your charger. But the charger is made to operate down to 100VAC for Japanese use (and even below that voltage; they're always overrated) so there will never be a plug in the USA that won't operate it, as long as there is power going to the plug at all, and we're not under severe brownout conditions.

2. There aren't USB "Charging Cables" and "Data Cables" as such. ALL USB cables can both charge and carry data. (Some permanently attached cords on chargers have a USB plug on the end but don't have data wires in the cables, but these aren't USB cables.) That being said, different USB cables can have different gauges of wire on the power conductors. I did a little research on this. If the wire gauge is 24ga, you can have about few tenths of a volt drop along a 3' cable at 1A charging current. A few tenths of a volt is tolerable by the charging circuit. If the wire gauge is 26, this changes to a full volt or more of drop along the cable and that can interfere with charging, causing it to charge at a lower current, so the voltage doesn't drop so much and remains at a level that the charging chip inside the Nexus 7 requires.

Note that a thick USB cable doesn't necessarily mean that it has thicker power conductors inside, but a thin one usually means that the wires are thinner. I would go with thicker overall cables and try several. Shorter cables, it's true, have lower voltage drop and would limit the charging less, but this doesn't mean that a shorter cable always charges faster. But if your longer cable is limiting charging current, a shorter cable will reduce this limitation.

Now, all that being said, the Nexus 7 has a 4325mAh battery, so for a 3.6 hr rated charging time it should draw an average current of 1.2A. LiIon batteries draw much higher current up front (at the beginning of their charging) and then trail off toward the end. So I would expect initial charging currents of 1.5-2A on a completely discharged battery at the beginning of the charge cycle, trailing off to under 500mA at the end of charge. LiIon charging of a sizeable cell usually shuts off at around 50-100mA charge current at the constant terminal voltage of 4.1-4.2V.

What this means is that for full speed charging you should use a 2A charger like it came with. A 1.5A charger would probably work, but it may heat up a lot and may limit charging at the very beginning a little bit (on a fully discharged cell) so it may take, say, 4 hrs instead of 3.6 hrs.


NOW... All that being said...

My research and experience leads me to believe that there are a certain subset of Nexus 7's that have a defect or assembly error (wrong current-set resistor or something) that causes them to limit their charging current internally such that it takes around 12hrs to charge.

My Nexus 7 has never charged quickly. I recently got a USB Ammeter that displays the charging current. I have my original Nexus 7 (ASUS) transformer as well as a number of other high-current USB transformers. What I have observed is that the Nexus 7 will never draw more than 430mA, and always exactly 430mA (with a fully or partially discharged battery) no matter if the unit is so dead that it won't power on, or when it initially powers on, or when the OS is fully booted, with lots of applications running or with none, with the display on or off. Always 430mA. Doesn't matter which charger I use (all are 1.5A-2A capable), doesn't matter which cable I use (I have 7 different cables of different lengths and thicknesses, even some very short 1-foot cables), and doesn't matter what wall plug I use (for you electrically superstitious types).

Notably, a 4325mAh cell would take about 10 hours to charge at 430mA, and since the charging current trails off toward the end, 12hrs is right on the nose, in keeping with the current that I'm measuring on my Nexus 7.

For those of you who don't trust my charging setups, my Nexus 10 charges at somewhat varying rates with different charges and cables (with a partially discharged battery) but all over 1A up to 1.5A on the same chargers and cables that my Nexus 7 limits to 430mA.

I know this thread isn't really active any more, but I'm posting this for posterity in case others find the thread as I did. If any of you have subscribed to it and have questions or comments about what I've said, please post and I'll subscribe and answer.
 

Danny Vaper

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Re: extremely slow charging, any fixes?

FYI, I'm an electrical engineer and I design, build and test LiIon charging circuits (among other things) so I know a bit about this topic.

I see a number of half-truths and myths about electricity and charging in this thread. The Nexus-7 specific information was true, that it should take 3.6 hrs, not 12 hrs, and any significant applications running can extend the charging time. Certain chargers and cables may extend charging time, more on this below.

The Myths:

1. No amount of extension cords or power strips or surge protectors on the A/C side of things can possibly affect charging. USA power is maintained between 110 and 125VAC. You might get a few fractions of a volt or a few volts drop over extension cords IF you have something like a space heater running at the far end of the cords where you plug in your charger. But the charger is made to operate down to 100VAC for Japanese use (and even below that voltage; they're always overrated) so there will never be a plug in the USA that won't operate it, as long as there is power going to the plug at all, and we're not under severe brownout conditions.

2. There aren't USB "Charging Cables" and "Data Cables" as such. ALL USB cables can both charge and carry data. (Some permanently attached cords on chargers have a USB plug on the end but don't have data wires in the cables, but these aren't USB cables.) That being said, different USB cables can have different gauges of wire on the power conductors. I did a little research on this. If the wire gauge is 24ga, you can have about few tenths of a volt drop along a 3' cable at 1A charging current. A few tenths of a volt is tolerable by the charging circuit. If the wire gauge is 26, this changes to a full volt or more of drop along the cable and that can interfere with charging, causing it to charge at a lower current, so the voltage doesn't drop so much and remains at a level that the charging chip inside the Nexus 7 requires.

Note that a thick USB cable doesn't necessarily mean that it has thicker power conductors inside, but a thin one usually means that the wires are thinner. I would go with thicker overall cables and try several. Shorter cables, it's true, have lower voltage drop and would limit the charging less, but this doesn't mean that a shorter cable always charges faster. But if your longer cable is limiting charging current, a shorter cable will reduce this limitation.

Now, all that being said, the Nexus 7 has a 4325mAh battery, so for a 3.6 hr rated charging time it should draw an average current of 1.2A. LiIon batteries draw much higher current up front (at the beginning of their charging) and then trail off toward the end. So I would expect initial charging currents of 1.5-2A on a completely discharged battery at the beginning of the charge cycle, trailing off to under 500mA at the end of charge. LiIon charging of a sizeable cell usually shuts off at around 50-100mA charge current at the constant terminal voltage of 4.1-4.2V.

What this means is that for full speed charging you should use a 2A charger like it came with. A 1.5A charger would probably work, but it may heat up a lot and may limit charging at the very beginning a little bit (on a fully discharged cell) so it may take, say, 4 hrs instead of 3.6 hrs.


NOW... All that being said...

My research and experience leads me to believe that there are a certain subset of Nexus 7's that have a defect or assembly error (wrong current-set resistor or something) that causes them to limit their charging current internally such that it takes around 12hrs to charge.

My Nexus 7 has never charged quickly. I recently got a USB Ammeter that displays the charging current. I have my original Nexus 7 (ASUS) transformer as well as a number of other high-current USB transformers. What I have observed is that the Nexus 7 will never draw more than 430mA, and always exactly 430mA (with a fully or partially discharged battery) no matter if the unit is so dead that it won't power on, or when it initially powers on, or when the OS is fully booted, with lots of applications running or with none, with the display on or off. Always 430mA. Doesn't matter which charger I use (all are 1.5A-2A capable), doesn't matter which cable I use (I have 7 different cables of different lengths and thicknesses, even some very short 1-foot cables), and doesn't matter what wall plug I use (for you electrically superstitious types).

Notably, a 4325mAh cell would take about 10 hours to charge at 430mA, and since the charging current trails off toward the end, 12hrs is right on the nose, in keeping with the current that I'm measuring on my Nexus 7.

For those of you who don't trust my charging setups, my Nexus 10 charges at somewhat varying rates with different charges and cables (with a partially discharged battery) but all over 1A up to 1.5A on the same chargers and cables that my Nexus 7 limits to 430mA.

I know this thread isn't really active any more, but I'm posting this for posterity in case others find the thread as I did. If any of you have subscribed to it and have questions or comments about what I've said, please post and I'll subscribe and answer.

Thank you for the post. I was beginning to think that there was something wrong with my N7, as it takes a very long time to charge from 40-50%. About 5 hours for a full charge from 45%. I'm assuming, after reading your post, that there is no way to decrease the charging time by switching to another adapter. At least I know my N7 isn't defective. Thanks again!

Posted via Android Central App
 

jyaneru

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** Fixed** Re: extremely slow charging

I think this problem is caused by different factors for different Nexuses. Some need to revert from the update, some need a replaced charging port, some have a loose battery, some need a different charging cable... and so on.

For me, I think it was either location services using too much power, or an app was constantly trying to auto-update (still using too much power). I was too lethargic to troubleshoot, so I fixed both:

After the terrible KitKat update: I flashed the stock operating system back on to my 2012 Nexus. It was noticeably faster, but still barely charging.
Then, I denied location services for all apps that requested it, and I turned it off in Settings.
After that, I went to the Playstore app and (one by one) unchecked "ALLOW AUTO UPDATES" for Each app I have installed (not just the downloaded apps, but the Google apps too).

NOW MY NEXUS IS USABLE AGAIN. The battery doesn't drain quickly anymore and the charging doesn't take forever. Also, FLASH WORKS AGAIN ^_^

I Do Not Plan to Update Again, without checking reviews or the forums for known issues...

I hope this helps someone else fix their slowly charging Nexus.


So I bought a Nexus 7 at bestbuy about 3 weeks ago and it was charging incredibly slow, about 12 hours to full charge and not being used, no matter what combination of charger and cable I picked....
 

James Brady

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Re: ** Fixed** Re: extremely slow charging

ah it sounds like your using a low amp charger....
the nexus charger is special and puts out 1.35amps
most usb chargers do from 0.5amps to 1amp

ipad 2.1amp chargers seem to work pretty decent....
but yea even when i charge mine on my iphone charger thats 1amp
it takes forever... like 6 hours.....and thats with the screen off.... if its on it doesnt charge at all unless im using the charger it came with... and then its very slow
 

Photo_Drew

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Re: extremely slow charging, any fixes?

Every once in a while mine will take forever to charge. Normally a couple of hours from 25% but once I left it overnight and it didn't fully charge. Finicky.

Posted via Android Central App
 

Relgoshan

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Re: extremely slow charging, any fixes?

I can't even see myself getting one of these as a toy after digging through the forums for the 2013 model this last week. I'll stick with what's been working for me.
 

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