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zxc314

Can the Nexus 7 be charged on any "normal" cell phone micro USB charger?

So maybe this seems silly as I don't really know what output a regular "cell phone" micro usb charger puts out power wise but with everyone complaining about it missing HDMI (which I too would like but isn't a deal breaker) or even MHL, what's being overlooked is that I believe this is the only major Android tablet that is charged via micro usb. This isn't earth shattering but does drive me crazy about other tablets and I see as a really big plus. Unless of coarse it draws more power and therefore needs a proprietary charger. I don't know if it does or not. None the less putting a standardized port on a tablet makes so much sense. It means I can pick up a charger almost anywhere when travelling (for cheap too) and can travel with just one charger for my phone and tablet to be. I have lots of micro usb cords laying around and wont have to worry about misplacing an expensive proprietary cable when I need to drop something on it from a computer. Anyway maybe someone can tell me if it can in fact charge via any old micro usb wall charger or not. But if it can, in my eyes this is just one more reason it is a very intentionally and thoughtful design element expertly done by Asus and Google. Really excited to start playing with the N7

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31 replies
TgD

As a caveat I haven't got my nexus 7 yet, but I do have experience in electricity and the pain of charging tablets.

The charger included with the Nexus 7 runs at 5Vdc/2A (https:­/­/play.google.com­/store­/devices­/details­/Addi...) and 2 amps is quite a bit of a power draw.

For USB 1.0 and 2.0 specs, a standard port delivers up to 500mA (0.5A) which my BlackBerry charger is. In USB 3.0, it moves up to 900mA (0.9A). The charging downstream and dedicated charging ports provide up to 1500mA (1.5A).

However, there are plenty of USB chargers that break these specs. Apple’s iPad charger, provides 2.1A at 5V. Amazon’s Kindle Fire charger outputs 1.8; and car chargers can range from 1A to 2.1A.

So where am I going with this? If you use a standard USB (less than 2A) charger, the Nexus 7 will probably charge, but slower than the stock charger. If you were to pick up a charger designed for the iPad or Kindle you would be in a better boat and charging speed would be close (or better in the case of the iPad) to stock.

Hope I helped!
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zxc314

That's some good and helpful information thank you. I guess I'll have to play with it when I get it.

Isn't there a concern for burning out the ac adapter? I know so many fools who have "barrowed" someone else's 13" macbook adapter to use on their 15" macbook pro and overheated or ruined the 13" adapter very quickly simply because they say, "oh it's the same size it must charge it!". (one reason I think sometimes a little differentiation specifically in the magsafe adapter would have helped people, but I digress). Anyway you're right we'll have to see I suppose. Just because the charger that comes with it is capable of 2 amps doesn't necessarily mean that the tablet will actually draw that much I guess right?
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TgD

Haha the 13" and 15" macbook pros use different Wattage (W) I happen to have both sizes of pros and their chargers are definitely not interchangeable although they look the same.

I feel like you should be fine on a USB level, but maybe someone else can confirm. Having a device that "can" draw more power than the adapter will provide should not mean it will force more power out.
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zxc314

Interesting, well I guess we'll just have to see. I haven't found many USB chargers that can output 2amps, none the less the charger for the N7 should easily charge my Nexus S which still leaves me with the desired outcome of one charger to charge them all. (my tried and true ipod class, Nexus S, and soon N7)
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sawilson

I've charged mine so far with: The charger that comes with it. The charger that came with my Galaxy Nexus. An old DroidX charger. The Nook Color charger (this charged it stupidly fast). Lithium-ion (or lipoly) battery charging is handled mostly in-device. The protection circuitry for overcharging and rapid discharge is built into the batteries themselves. The worst thing that can happen is:

1) You'll shorten the life of the battery by fast charging it. Not a huge deal on the nexus because it's pretty easy to change the battery yourself worse case.
2) It will take a day and a life to charge.

Apple is doing something different with their chargers because their batteries are either impossible to replace, or damn near impossible to replace. They need to make sure their battery lasts just until your warranty expires.
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usercf49d9f498d

I wish you were right. Unfortunately, the N7 doesn't seem to like any of the chargers that I use for our iPads — no Apple's own, not Belkin's, not the Amazon Basic, and none of the various eBay cheapies with which we've equipped our home. If anyone can figure out what Asus did to make the N7 so choosy, I'd love to hear it. I really want to believe there's a good engineering-related reason for it.
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usercf49d9f498d

UPDATE: I turned up a 200 milliamp, unbranded unit that merrily lit up the lightning bolt icon on my Nexus 7 and charged it overnight. Go figure. I give up.
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rbmiller

Actually, the Nexus 7 will charge from either my Radio Shack dual tabllet/phone charger at 5V=1.5 amps or my Blackberry Bold 9900 charger at 5V=750 Mah. The former charges the device almost as quickly as the OEM. The Barnes and Noble Nook, on the contrary, requires the proprietary cable to work.
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kernco

I learned the hard way that just because the plugs are the same doesn't mean they're interchangeable. I tried charging my iPad through a wall socket, but didn't have the wall socket to USB converter, so I used the one that came with my kindle. It doesn't work at all now; I think the iPad tried to draw too much power through it.
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zxc314

Yeah this is one of the small (and frankly disappointing) design oversights apple seems to have fallen to. It's really silly annoying and could probably be avoided pretty easily.
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pika2000

iPad charger doesn't work on my N7.
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usercf49d9f498d

Nor on mine. Asus really pulled a fast one on users here. The iPad is a heck of a lot more accepting of third-party chargers, in my experience.
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uberrob

You stated this beautifully....I have nothing really to add other than this rule of thumb: if you have a USB charger that you got with a product within the past 18 months, it will probably work - but, as TgD says.....SLOWLY. (So, don't leave the screen on while charging on these.)
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TgD

Just to follow up on my own post. My Nexus 7 charges using the Galaxy Tab P1000 charger, and the galaxy tab 8.9 LTE charger, and also (no doubt more slowly) plugged into my macbook pro
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fishd

I can tell you that the Nexus 7 comes with it's own USB charger, which I've left in the box as the device has a standard micro-USB port on the bottom.

However, it won't charge from a 4-port Kensington USB power adapter I have, nor will it charge from the iPad USB charger. It will charge (slowly) from the USB port on my Mac Pro and it will charge and seems to charge quickly enough from the Amazon Kindle 3G USB power adapter.

Hope that helps.
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pika2000

Just to add, I have 2 different Belkin surge protector with USB charger, none of them works. Zune charger, nope. ZAGGsparq battery pack/charger works, but only on the General port, not the optimized port.
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usercf49d9f498d

CAN HARDLY BELIEVE IT. I came to GDGT today hoping this charging issue was unique to me. NO. Asus must've engineered this to fail on anything except for the Asus charger. Our home is swarming with chargers of various makes that all work on the higher powered third-generation iPad, which you would think might be more finicky. No, actually it plays nice with my cheapo chargers off of eBay. Yet NOT ONE of them, and not even the official iPad charger, works with the Nexus 7. Nor do the USB ports on my wall plates, which are designed to charge at 2.1 A minimum. In fact the only thing I can charge this thing with is the Asus unit that came with the Nexus 7.

NOTE TO GOOGLE: This will drastically limit its use to only one floor in my home — I'm hanged if I'm going to tote that black Asus wall wart up- and downstairs with the tablet. Every other shortcoming in the N7 -- the lack of MHL support and SD cards, for example — seems designed to drive you to Google's play store, to buy streaming media or the (shudder) Nexus Q. I resent those, but understand that if I want a good price, I have to play Google's game But this one mystifies me, unless it was a profit-margin-fattening sop to Asus. If I sound p*ssed about these things, it's because otherwise I really like this tablet a whole lot. If I didn't, I could care less. Google got SO MUCH about this tablet right, that I'm upset about this absurdly simple stuff that's going to trip people up.
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sawilson

If it makes you feel any better, you payed less than half of what you'd pay to have the exact same problems with the iPad. I'm sorry you had bad charger luck. I have 3 different non-asus chargers that work great with mine.
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usercf49d9f498d

@zxc314: I do like that it can be charged with a standard CABLE, but the Nexus 7 is quite finicky about the actual charging UNIT.

UPDATE: I said yesterday I could charge it only with its accompanying Asus unit.

After going through my drawer, however, I have now uncovered a few more chargers that it seems to like. This motley assortment includes my Samsung Galaxy III s converter, my old EVO 4G plug from HTC and a no-name wall-wart that cost maybe 99 cents plus shipping from a Hong Kong vendor on eBay. None of these are rated any higher than 2 amps.

In fact, it merrily charged last night on the Hong Kong unit -- rated only at 200 milliamps!

Yet it spurns ALL the various 10-watt, 2.1 amp chargers I use for our iPads.

I have no idea why. If i can figure it out, I will post.
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usere91cff9a5a2

Just unboxed my Nexus 7 yesterday and plugged it in with the charger (wall outlet) for my Samsung Galaxy SII Skyrocket. It was handy and already plugged in at my desk here at the office. Seems to charge ok but really slow. Haven't tried the included cord yet so will be interested to see if that's faster.
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BoBraxton

When Nexus 7 arrived, I charged it "overnight"
After that it seemed to work well.
Then a week or so ago, I am getting battery (lightening bolt) icon but no Droid desktop.
The only charger I have used is the included one. Don't know where to go from here.
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usere91cff9a5a2

Do you mean it's off when you say no desktop? I'm confused. If you plug it in to charge when it's off you'll only see a gray battery icon with the indicator moving up as it charges. Then there's no desktop. If you have it on and charging gives you no desktop it sounds like you might need to contact Google for support.
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BoBraxton

For two days I charged, using the supplied wall charger (with USB).
Once it appears fully charged, I removed the cable and again saw the "X" followed (eventually) by Google and some updates completed. Nexus 7 seems to be working fine. I am grateful. Thank you.
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usere91cff9a5a2

Glad to hear it!
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usercf49d9f498d

Now that I've lived for a couple of months with the Nexus 7, the charging issues bother me a bit less, because I've found that about half my charger collection suits its whims. Unfortunately, NONE of the iPad-friendly chargers make the lightning-bolt appear, but that's da breaks. I'm wondering now if Google specs a special polarity or something else for Android chargers, because all my chargers that CAME WITH ANDROID DEVICES work on the Nexus 7, no matter how puny. Practically no third-party chargers do the trick, but I've got plenty of options now -- because my Android phones work with almost ANYTHING that plugs into a wall, including all my Apple units. It's just the Nexus 7 that proves so finicky, and I'm thinking now it's a Nexus thing. QUESTION: Does anyone have a Nexus phone with similar characteristics?
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TheByteSmasher

You'll get the lightning bolt with an Apple charger with this: forum.xda­-developers.com­/showthread.php­?t­=1984838
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ItsMeNow

Mine will charge from the standard Samsung Galaxy Sii supplied charger and using its own micro-usb cable it will only charge from my laptop.

However, I have a USB battery pack which came with its own cable and the Nexus will charge using that cable from pretty much any USB (presumably slowly!)

I would add a note of caution - I did hear of a guy charge it from his phone charger, it couldn't take the power draw and burn-out killing the Nexus in the process.
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Fythios

I am apologize if this is a bit of a late reply but maybe it might help someone who wants to know why their apple charger does not charge the Nexus 7. I've run a couple quick test to see why.

I've done a little homework on the apple charger and know that the data lines receive 2v and 2.8v to cause it to limit the charging to 1 Amp (as per www.ladyada.net­/make­/mintyboost­/icharge.html) Interestingly enough once the iPad has received these voltage on its data lines, it continues to charge at the current rate even if the data lines are disconnected.

This unfortunately does not cause the Nexus 7 to indicate it is charging. Though the Nexus 7 does draw some amperage at around 600mA. I have yet to test it while it's off. However if you short the data lines out, it causes it to charge and draw maximum amperage that Nexus 7 wants to take in (or in theory should from what I have seen it has drawn in a little under an amp with no load, it's on but idle.) I have tried putting the data lines to ground with no success, I intend to take a look at the provided Asus charger and see how it operates.

Now even more interestingly, "A simple USB charger should short the 2 data lines together. The device will then not attempt to transmit or receive data, but can draw up to 1.8A, if the supply can provide it." (pinouts.ru­/Slots­/USB­_pinout.shtml). Both the iPad 3, iPhone, and Nexus 7 all respond to this and charge accordingly. I don't recommend doing this as it may draw too much amperage for a supply and burn it out.

And as a last note a lot of charges out there are iPhone/ iPad compatible which is why they won't charge the nexus 7. Sad to say apple has dominated the market for how wall chargers are to be built if they want to work with apple. If I turn up anything new I might post it but I'm already a bit late in the response now.

-Edit-
A small warning out there about cheapy wall warts / AC to DC convertors. While there are a lot of switching convertors out there they all don't necessarily regulated at 5 volts and allow for high current. Please be careful what you use to charge your new toy or as some users experienced their charger can draw too much amperage and burn out a low amperage regulator or IC. This could easily cause a short thus killing the device too.

-last Edit-
Well I did some quick digging that I should of done earlier on XDA about the charger issues.

"CONCLUSION:
1. Nexus 7 OEM charger is nothing special, just the data pins are shorted.
2. Nexus 7 OEM MicroUSB cable is nothing special. It is a standard MicroUSB cable.
3. Any USB car/wall charger should charge the Nexus 7.
4. Nexus 7 will charge regardless of whether it displays "AC Charging" or not.
5. The charging rate is dependent on the capacity of the charger and the total charging circuit impedance (lower the impedance the better).
6. Increasing the length of the cable increases the charging circuit impedance and decreases the charging rate."

forum.xda­-developers.com­/showthread.php­?p­=29983624...
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ferntree

OK - i tried a selection of eBay usb chargers, Brookstone and genuine ipad chargers and none would charge the Nexus 7. I then changed my micro cable to a good quality one (from my MiLi power pak), and guess what - all my chargers now charge the Nexus 7 - Bonus!!

It would appear that the Nexus just happens to be fussy about cable quality.
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TheByteSmasher

Look here: forum.xda­-developers.com­/showthread.php­?t­=1984838
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anonymousses

Can the Nexus 7 be charged on any "normal" cell phone micro USB charger?

This is system problem, probably software|hadrware related (Nexus does not want to be FAST charged by not original adapters).

Anyway maybe someone can tell me if it can in fact charge via any old micro usb wall charger or not.

YES & NO. I can't find answers or recipes. Of course, XDA theme says [SOLVED]. ILOL'D. Any good charger allows only 0.8Amps, this is NOT charge, this is only palliative. My maximum from not original charger - 1Amp. But I found one model (of course, this is not final sentence, i think you, people, can find more devices), that supports quick charge @ 1.5Amps!

I try about dozen of devices and now stop my searches...

This is SONY - quick charger EP881.
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