yashsingh1/xdaforums huggingface dataset:
[Nexus 7 Accessories] jeremy8000:
I can confirm that the Rocketfish Model: RF-MCB55 charger (12v, 2.1A) works great and matches the OEM charger in charging speed. I can't post a link, but it's:

www . amazon com /rocketfish-mobile-Micro-Model-rf-mcb55/dp/B004MF17FG

*Note - it has an auxilliary USB port for connecting another device (e.g., phone), but the total output for the charger is 2.1A, meaning that if you connect another device to it you do drop the amperage output to the Nexus 7 (I haven't tried it, so don't know what sort of impact it would have on the tablet's charging speed).
[Nexus 7 Accessories] nevertheless:
I have seen ratings on this charger of 600ma. google mcb55 600ma. it goes for $3 on ebay shipped. I don't really believe they would sell a 2.1a charger that cheaply. but stranger things happen in life. nobody lists it as having an AUX USB port for another device either.
[Nexus 7 Accessories] kardain:
This....

http://www.amazon.com/Belkin-USB-2-0-4-Port-Hub/dp/B0051QZEHC

Plus a monoprice usb cable or three will charge my n7, flyer, and n1 at the same time, albeit slowly...

No clue how to figure out how many mA it puts out to each device though.

|-|-|
[Nexus 7 Accessories] pache711:
I have not been able to get any of my 2.1 amp chargers to work. There has to be something else to it.
[Nexus 7 Accessories] morphiend:
anyone try either of these?

wall charger

http://www.amazon.com/PowerGen-Charger-Samsung-Motorola-included/dp/B0073FCPSK/ref=pd_bxgy_pc_img_b

car charger

http://www.amazon.com/Mediabridge-High-Output-Charger-iPhone/dp/B007TV88F2/ref=pd_cp_cps_2
[Nexus 7 Accessories] janedoesmith:
As for the car charger it was reported to not work.

http://xdaforums.com/showpost.php?p=29409132&postcount=13
[Nexus 7 Accessories] morphiend:
that's a bummer. thanks for the headsup. i was about to get it too.
[Nexus 7 Accessories] tom_yellowblue:
The problem is that the chargers are mostly configured to work with Apple products since they're so popular. They do this by using resistors on the data pins to let the device know how much current it can draw.

I fixed the problem by making a charging cable from a spare cable. To make a USB charging cable, open up the middle of the cable and short the two data pins together (usually white and green) on the Phone/Tablet side. Leave the data pins floating on the charger side so the charger doesn't get messed up. I've noticed a lot of people trying to short the pins on the charger side; that usually doesn't work.

Here's the pinout:

Pin Signal Color Description

1 VCC red +5V

2 D- white Data -

3 D+ green Data +

4 GND black Ground

This worked for me, my Nexus 7 charges on every charger I've tried. Don't blame me if it blows up your tablet. :)

I haven't tried it, but maybe a cord like this would work if you don't want to build your own:

http://www.amazon.com/Naztech-Micro-USB-Charging-Cable/dp/B003VYBCAY/

=-=
[Nexus 7 Accessories] qoncept:
Those monoprice cables won't charge mine (well) even with the oem charger
[Nexus 7 Accessories] nevertheless:
I would not charge n7 from a USB hub. but that's just me. people. there is fantastic OEM wall charger that you can buy for $4.50. it's in the thread.
[Nexus 7 Accessories] el56:
Would this one work?

While going online, looking for 2A or 10W chargers that didn't have the iPad wiring kludge built-in, I came across this iGo charger that claims to be a dual-port USB 2.1 charger that is explicitly not compatible with the iPad.

I've had iGo products before and been happy with them. Does anyone have experience with this one?
[Nexus 7 Accessories] player911:
I think there is something screwy going on here. I have a Griffin 2-port USB Car Charger. I have soldered the 2 data pins to allow full speed AC charging. I verified it works by using my Galaxy Nexus which detects it now as AC. The N7 doesn't even recognize it.

Most of my Wall Chargers in the house have been replaced with at least 1A output units so my Galaxy Nexus would charge anywhere.... and the N7 doesn't have a problem with using a 1A charger, it's just a little slower (still twice as fast as USB).

But my car charger is different entirely. It is a 2A total unit. I have a 6th gen iPod (the little squares) on one leg and a microUSB cable on the other. It is a great setup but it just won't pass power to the N7. I haven't tried replacing the cable yet but it's soldered at the charger, the cable data pairs shouldn't matter at that point.

I also have several iPad chargers, thinking they would provide enough power... nope. Doesn't even see it. The Galaxy Nexus doesn't either. POS Apple.
[Nexus 7 Accessories] tom_yellowblue:
Really, try a charging-only cable. :) I've used mine with 3 separate wall chargers and 4 separate car chargers and every one shows up as charging from AC. I haven't actually measured the charge rates, but if I try it with a normal cable it doesn't even show up as charging at all. Just make sure you don't short the red and black wires. This is what you need to do... please forgive my crude ascii art...

micro-USB fullsize USB
side side

red ----------------------
white ---------\ -------
|
green ---------/ ---------
black ----------------------
[Nexus 7 Accessories] tengtengvn:
I tried that when I first got mine 7. The first victim was the Samsung USB cable. That didn't work. Didn't wanna waste anymore good working cables, I tried that with a USB male to female extension cable.

It came out some cables work when I connect to the power-only extension cable while others don't. Really weird.:confused:

Right now I'm using it in the car with a 2A charger that didn't work before. Not sure how fast it charges the 7 but on my way to work it keeps my tablet at 100% with Nav or Video running.
[Nexus 7 Accessories] Entropy512:
That's odd, as all of my MicroUSB cables have longer connectors than the stock one...

CurrentWidget requires the kernel to export the charge current reading in sysfs. I don't remember the location, I'll look it up tonight or tomorrow. Many kernels don't support this - for example, Samsung Galaxy S2 kernels didn't support it at all even though it only required 2-3 lines of code added to the kernel!

Battery Monitor Widget is notorious for "pulling numbers out of its ass" - displaying current based on battery percentage change and an assumption of battery capacity, not an actual current measurement. Some of the screenshots are saying "estimated" for current, which is more evidence that points this way.

Since it says it's for iPad - most likely not.

I won't be able to take a look at the charger voltages with a meter until tonight or tomorrow (busy night tonight). My suspicion from the various reports is that it follows the USB charging standard (+ and - must be shorted by the charger), but some cheap cables have MicroUSB male connectors that are too short and don't properly insert fully. I'd need to take a closer look.

FYI, this is how Samsung Galaxy Tab units worked, they didn't quite follow the standard:

If D+ and D- were not connected, it would charge extremely slowly. No charging would be reported when the device was on, it would report charging when off.

Same for if D+ and D- were shorted but not tied to a given voltage

Same for if D+ and D- were at voltages set by iDevice chargers

The only time it would charge rapidly was if:

D+ and D- were shorted AND held at approx. 1.8-1.9 volts

It was possible to modify iDevice chargers to do this by shorting D+ and D- together, then removing one of the two pullup resistors.

Edit: I'm seeing reasonable charging performance from an older HTC 1A charger and a Monoprice cable - one of their "premium" ones (24/28AWG with ferrite - I assume these are 24AWG for power 28 for data). This says to me that the N7 is most likely following the official USB charging standard (short D+ and D- together) and that the few cases where it doesn't charge at all even if the charger shorts the cable are crappy cables that have too short of a male MicroUSB plug.
[Nexus 7 Accessories] morfinx:
Just want to add that the "Innergie mMini AC 15 Dual USB 15 Watt Power Adapter" does NOT work:

http://www.amazon.com/Innergie-mMini-Adapter-ADP-15AB-AA/dp/B005JZP3IU
[Nexus 7 Accessories] teufeldog:
I'm having troubles with power adapters too. Just got this N7 today.

The included ASUS power adapter, an HTC G2 adapter, and a Galaxy Nexus adapter all work.

My Twelve South PlugBug, and Apple's iPad power adapter all fail to charge the device.

I tried a bunch of different USB cables (Kindle, ASUS, HTC, Samsung). It didn't matter which cable I used, none of them would work with the PlugBug or iPad adapter and the N7. They all work find when charging other devices though.
[Nexus 7 Accessories] w0mbl3:
Tom's on the ball and correct - although I prefer to mod the chargers rather than the cables (saves having to dig around for "the right" cable). Most of the ebay cheap chargers contain the correct resistors for passing particular voltages to the ipad/phone/pod according to apple's proprietary signalling scheme.

I've modded a couple of cheap ebay AC wall chargers, and a couple of car cigarette-to-usb chargers and all show (AC) charging when plugged into Android devices, so that we could charge our phones faster. I just got my Nexus 7 a couple of hours ago - I'll grab the Battery Monitor Widget and go test out my modded 2A charger (4-usb port) that we use in the kitchen for various family phones.

Its usually pretty easy to de-solder the resistors from inside a cheap ebay iPad charger, and then bridge the two data pins with a bit more solder. I have pics somewhere of a couple of the chargers I've done - I originally found a really good thread in the Galaxy Nexus forum (I think - it was definitely one of the early Nexus phones).
[Nexus 7 Accessories] morfinx:
Just want to confirm that this charger does work with a modded cable where the data pins are shorted on the device side. I had a very short USB extension cable that I used for this experiment.
[Nexus 7 Accessories] AraDreamer:
Can we get an updated list in the OP or a google doc that posters can add to? (Like the 'good apps' list in themes)

-Ara
[Nexus 7 Accessories] qoncept:
Good idea, I'm working on setting up a google doc now. There's going to be too much to keep up with.
[Nexus 7 Accessories] Entropy512:
It's listed as an iPad charger so this isn't surprising.

See above - iPad chargers are not detected by any Android device I'm aware of as a proper charger.

In many cases (I haven't tested this on my N7 yet), you don't even have to desolder the resistors - they're high enough value that the method of sensing whether D+ and D- are shorted overrides the weak voltage divider.

For example, the Scosche charger that I've modified to charge my Tab 10.1 (short D+ and D- with a solder blob, remove one of the pullups to drop the voltage a little) gets detected as a normal "shorted with no pullups/pulldowns/voltage divider" charger by my phone. Have not tested my N7 yet.

So far it's looking like the N7 is just like most Android phones in that it follows the USB battery charging specification - the main exception is that some MicroUSB cables have male plugs that are too short.
[Nexus 7 Accessories] crasch:
Samsung ETA0U60JBE

I've just tried my Samsung Travel Adapter with the Asus Cable.

model: ETA0U60JBE

Output: 5.0V @ 0.7 amps

Got the indicator, but I don't expect it to charge very fast since it's on 0.7 amps.
[Nexus 7 Accessories] teufeldog:
I can charge my Nexus One, HTC G2 and Galaxy Nexus using both the PlugBug and the iPad charging adapter. They just won't work with the N7.
[Nexus 7 Accessories] goofball2k:
The charger for the BB 9300/9800/9900 work. The ones I have for my iPad's don't. None of my car chargers work either :( Will have to resort to using an inverter in the car, i guess.
[Nexus 7 Accessories] Entropy512:
They are charging at reduced current (<500 mA) as most such devices assume a PC USB host or "misc" charger when they see iDevice voltages on the data lines.

Samsung Galaxy S and S2 series devices charge in USB mode when an iCharger is connected.

Samsung Galaxy Tab series devices refuse to charge over USB, and hence won't charge when an iCharger is connected. (They, like the N7, may charge slowly without reporting charging.)

The Nexus 7 seems to have some additional methods for differentiating between "misc" and USB - If it does not enumerate with a PC host, it assumes "misc" and refuses to charge unless D+ and D- are shorted (which indicates a "dumb" charger).

Nearly all chargers in my possession have D+ and D- shorted, and the N7 happily charges from all that I've tested so far.
[Nexus 7 Accessories] slybunda:
best not to use cheapo chargers that put out dodgey ripple and voltage specs, always use a good quality charger than a cheapo high amperage charger.

i phone charger i can confirm works, but its slower than oem charger.

also last night i had the nexus7 on charge with my computer, from 27% when i put it on charge to the morning about 7 hours of charge time it showed 44% charged,

i was using a 1.5meter usb extension cable and then the oem cable attached ot the extension cable.

as you can see the charge was too slow. pc has gigabyte p35t-dq6 mobo and corsair hx620 psu.

need to see if i can get a proper high quality 3 amp charger. the oem one does tend to get a bit warm, but then again so does the iphone charger i have.
[Nexus 7 Accessories] nevertheless:
with 1.2a nokia charger, n7 charges up as fast as oem. n7 doesn't need 2a. it just needs to have the shorted charging cable.
[Nexus 7 Accessories] joed1ver:
Won't work with apple stuff

My experience is that with any charger designed for an apple product won't charge the Nexus. I've installed the Nexus is my car dash and have been trying to find a good dc adapter.

I took two different adapters, one had both ports set for apple, the other had one. The one non apple would charge slow. Only after I removed the resistors on the data lines and shorted them together would the apple ports charge the Nexus at all.

I put a meter in series with the wiring to test the current. They say their rated at 2A, but the most I saw was 600ma. Typically, it was running at 575ma and the Nexus indicated AC and it was charging at that rate, though slowly.

I had both wifi, BT, and was running a video and got the same results. This was using a cheap, generic cable (I need a right angle micro plug for it to fit where I mounted it).

Still don't know what the answer is...
[Nexus 7 Accessories] Entropy512:
The datasheet for our charger chip (Summit SMB347) indicates that it has a feature to automatically limit current if input voltage drops (for more universal charger compatibility, since it's impossible to determine exactly how much a given DCP is rated for).

It seems that it is set in the N7 to be pretty aggressive - Long cables will reduce the current, and I think there's a good chance that the resistance of the ammeter, while small, is enough to cause a voltage drop.

Can you try CurrentWidget with http://review.cyanogenmod.com/#/c/20891/ instead, and put the meter in parallel to measure the charger voltage when charging? I wasn't able to get out the door in time today to get to the electronics store and buy a cable to cannibalize and some banana plugs.

My observations:

Tab 10.1 charger reports 1400+ mA charge current in CurrentWidget

Stock charger reports 1200 mA or so

A modified Scosche iPad car charger only does 600-800

It seems like many iPad chargers may not be meeting their rated specs...
[Nexus 7 Accessories] joed1ver:
Entropy512:

I'll check it out in the morning and post my results.
[Nexus 7 Accessories] joed1ver:
Some more charging results.

Current Widget gives me "No Data", however I am certain my testing procedures insert very little error into the readings.

I also was running Battery Meter Pro, but it's estimates were off by double.

With a generic 1A/2A dc adapter using the original cable from my Nexus, and the battery level at 87%, I was getting about 840ma @ 5.33v

Using a Startech 3' w/ right angle micro I was getting 620ma @ 5.33v.

Using a generic 6' cable from Altex I was getting 530ma @ 5.33v.

I used two different but similar adapters and got the same basic readings.

These readings were taken one after another twice with the same results.

The Startech cable is probably using smaller gauge wire due to it's diameter, but the generic cable appears to be the same as the original, though it's longer.

Cables matter.
[Nexus 7 Accessories] Entropy512:
CurrentWidget will only work if you apply the linked patch to a custom kernel. :(

That's odd - I've never seen a charger run that "hot" - 5.33 volts under load.

That's strange... I see 5.0 volts unloaded from my Tab 10.1 charger, 5.1 from the Nexus charger, I have not yet had an opportunity to measure the voltage under load.
[Nexus 7 Accessories] sensimila:
Is anybody using external battery packs?

---------- Post added at 03:20 AM ---------- Previous post was at 03:15 AM ----------

What about charging from the PC, mine will not recharge as fast as the OEM charger.
[Nexus 7 Accessories] nutley:
I have the first version of one of these http://www.amazon.co.uk/Scosche-reV...NO4Q/ref=sr_1_8?ie=UTF8&qid=1345022289&sr=8-8

Using the 2.1A port and stock cable it charges the N7 pretty quick but it doesnt say that it is charging
[Nexus 7 Accessories] Entropy512:
I have the same device - even after modifying it to properly charge standard devices (Short D+ and D- together), it does not appear to be capable of 2.1A despite its claims. N7 limits itself to 800-900 mA or so for example. I need to retest but I think it also charges my Tab 10.1 fairly slowly. (will test tonight)
[Nexus 7 Accessories] devra1:
Yes I am charging fairly quickly with an XTPower MP-10000 Powerbank, which is a external pack with 10000mAh, 2xUSB and 1x DC output (9v or 12v), including 17 Adapters.

I use the "S" USB output which is meant for Samsung devices, together with the OEM cable. The "I" USB output is meant for Apple devices.

It was invaluable while touring England last week because I could charge the pack from the car 12v socket.
[Nexus 7 Accessories] Singingdrum:
I have discovered that the cable from the Nook Tablet has the exact same micro usb end that the Nexus 7 has--the exact same markings. So apparently both cables are made by the same company. The Nook cable charges in my Nexus 7 fine.
[Nexus 7 Accessories] crgrissom:
I can confirm that the New Trent iCarrier 12,000mAh works as AC charger with both the included micro usb tip and this cable:

(can't post link, but found on ebay: Universal Micro USB Charge Only PureGear Cable)

As noted previously, this battery does NOT work with the N7 stock cable.

I'm going to try this cable with various other 2A chargers that have not worked before to see what happens.

Interestingly, this cable also works with my iPad charger and registers as AC charging on my N7.
[Nexus 7 Accessories] Entropy512:
Yup. What the cable is doing is shorting D+ and D- internally within the cable, making whatever the charger does irrelevant.
[Nexus 7 Accessories] ppp38:
I just received this cable as my official Asus cable was damaged and no longer works. That being said, its not charging my N7, it works while plugged in but my batter never charges past 0%. Is anyone else having this issue?
[Nexus 7 Accessories] janedoesmith:
Does it have any kind of writing on the cable itself like "28awg/1p 26awg/2c"?
[Nexus 7 Accessories] ppp38:
No, the only thing it says is MediaBridge Highspeed 2.0 USB. But, turns out it is charging just incredibly slowly. I would not recommend this MediaBridge USB cable to anyone else.
[Nexus 7 Accessories] janedoesmith:
See here.

http://xdaforums.com/showpost.php?p=29983624
[Nexus 7 Accessories] stuartmc:
I have followed this and several other threads on Chargers since buying my Nexus 7 a month ago. I would like to share my results briefly -- what I purchased and what has worked.

For wall charging I purchased through Amazon the RND power station that has three AC plugs and two 2.0 amp usb ports. Here is the link to it:

http://www.amazon.com/gp/product/B006O44OSA/ref=oh_details_o01_s00_i01

There are a lot of units on the market that look exactly like this and for all I know, they are all the same.

For car charging, I purchased the Anker 3A dual usb plug: http://www.amazon.com/gp/product/B0080AWCTY/ref=oh_details_o01_s00_i00

To correct for the "don't see it as charging full current" problem with non-apple devices, I tried two solutions that each apparently short out the data pins. One is the Pure Gear charging cable: http://www.amazon.com/Charge-PureGear-Retail-Package-Universal/dp/B007F1DV76 and the other is Power+ USB filter plug that allows you to use any data cable: http://www.amazon.com/gp/product/B007IXBTCK/ref=cm_cd_asin_lnk.

I can report that the wall charging unit works great with both the Pure Gear cable or the Power+ adaptor. The Nexus 7 identifies it as AC charging and the charging speed is as good as the the stock charger. No other regular cable (alone) works with this wall charger.

The same results were had with the Anker car charger - both the Pure Gear cable and the Power+ adaptor combined with a standard cable, worked perfectly. As a bonus, this charging combination is now charging my Samsung Infuse cell phone much faster...undoubtedly, it is now drawing higher current from this charger.

This is my way of saying thanks to all of you who posted earlier and assisted me with my purchases.

Stuart
[Nexus 7 Accessories] CloudDog23:
My ASUS power block gave up the ghost while I was away last week. I tired a different cable, and it still didn't work. I tried my HTC phone charger power block and that worked fine, I tired the Nexus cable with the HTC power block and that worked fine. I tried my HTC in the ASUS power block (with both the HTC and ASUS cables) and that failed. So I summarised that it was the Power Block. Google support will be sending me a whole new Nexus 7 and I have to send my Nexus and power block back. They are unable to send just a replacement block. What a waste of everybody's time and money.
[Nexus 7 Accessories] psycho2097:
Idk y but I never faced any significant issues with my n7 charger wise.my gnex charger charges it at 1a, my mifi router cable charges at 1a, n a cheapo external power bank charges at 1.5 ish A( it says 2.1A). Attaching pics of the same.
[Nexus 7 Accessories] Troute:
The only problem with this is that it causes interference on FM radio, it's a common problem with high power car chargers though.
[Nexus 7 Accessories] Entropy512:
Surprised that Power+ adapter worked, since it advertises allowing iPads to charge - I would have expected you'd need a different adapter for standard devices.

Similarly, I can't see how you actually had increased charge performance of the Infuse. That device charges at 600 mA maximum regardless of charger capability unless you have a modified kernel (such as my charginghacks kernels), and even then it maxes at 800 mA input which the stock charger seems to have no problems delivering despite being rated only for 700 mA.
[Nexus 7 Accessories] joed1ver:
Entropy512,

Is your source code for a charging hack available for the Nexus? I read a note from you back in April where you directed someone to the code for a Infuse 4G. I can't even spell programmer, but have managed to compile a ROM using the "Build CM10 for Nexus 7" post and would to add the charging hack if possible.

Thanks.
[Nexus 7 Accessories] xerxes:
The Nokia AC-10X also works perfectly.

It's a 1.2A wall charger with about 5 feet of cable built in.

It seems to charge at about the same speed as the OEM Asus charger.
[Nexus 7 Accessories] silentdth:
Just bought a rockfish micro USB car charger from best buy for 15 dollars on special. In the cellphone section. It works!

EDIT - update ***

Only charges slowly and only with GPS off. Do not recommend.