Device(s): RAZR MAXX HD (Jelly Bean), OG RAZR 32GB (Jelly Bean), Nexus7 (Jelly Bean)
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proprietary USB charger???
I thought I was getting away from this and the XOOM and it's lame proprietary charger, but this newly arrived Nexus 7 (which is peppy, I do like that) only seems to take a charge from it's USB charger (or the PC). This *stinks* because I use a built in wall charger by my bed, and I have a specific folding travel charger that I use on the road - neither charges the Nexus! So now I have to plug the proprietary USB charger in the wall by my bed (which then sticks out 4" requiring moving and rearranging furniture) and also pack it along with everything else for trips (just what I need -1 more thing!).
*sigh* can't we all just get along on the USB and related USB functions???
I haven't had any problems using my Moto wall charger and it. What I do have is my TF Prime only takes its wall charger or just gets a trickle from others (incl the N7 one). None of our phones have problems with any of them. Does suck, I know. At least it's not a proprietary INPUT like my Flyer has.
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Odd. I have no issue using whatever charger I happen to grab and plug in. I actually very rarely use the one that came with it. One thing that does occur to me is that when the original Asus Transformer came out, we all found out that you couldn't use just any charger. If I remember right, I think it used a USB3 cable and not the usual USB2 that most people use. There seems to be certain pins on the 3 cord that aren't there on the 2 cord and that caused issues. Since this is still an Asus product, I'm willing to go with that theory.
Keep in mind that the N7 has a MUCH larger battery than any phone, so a phone charger will take a very long time to charge it. I think the N7 charger has a 2A charging output, vs 1/2A for the USB port in a PC/Laptop, and maybe 750mA-850mA on most phone chargers.
I use mine mostly at work at night (don't let the boss know) and there are always a bunch of different phone chargers laying around. Never had an issue using any of them. Of course some charge slower than others but all of them charge for me.
I'm sure I remember reading (in this forum) that the N7 detects what type of charger it's connected to and adjusts the charging rate accordingly. It may be that it thinks your charger is a PC and it's keeping the charge rate down so as not to overload the PC's USB bus.
Last edited by jhsrennie; September 30th, 2012 at 02:36 AM.
Reason: Correct typo
My point is, you need 2 amps if you're going to charge at the fastest speed.
If it's powered on, with a charger that's too small, you could actually lose a charge, if it can't keep up.
Ahh, yeah, I gotcha.
If you aren't using the tablet, though, even a 500 mA charger should keep up. 4300 mAh battery, if you are discharging at 500 mAh, would last ~8.6 hrs. That's way less than the standby time of the tablet, so it should at least take a small charge.
The chargers for my Motorola phones, Kindle Fire and Kindle Touch all work on my N7. Honestly, I haven't paid any attention to whether it takes longer with one or the other. I just keep the N7 charger at work, in case it needs charging while I'm there.
I've owned a few eInk Kindles and use the white charger because of the extra long cord. It definitely charges the N7 at a very slow rate. It's not a problem if my goal is to charge it overnight. I'm realizing I do need to start making use of my N7 charger for quick charges.
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I've a 0.3A charger, which only charges the Nexus 7 when it is switched off - slowly, too.
The N7 seems to charge fine when switched on with any charger rated over 1A. I've an iPad wall charger with 2 USB outputs, which is great because it will charge my Nexus 7, TF101, PS Vita, SGS2 and Sony P&S camera without problems (only two at a time, obviously). Makes travel packing very much easier!
I suspect its not proprietary (like the bizzare iphone/iphag truely proprietary WTF charging scheme). The Nexus7 just picky about voltage. If you use a usb cable that is even a little bit longer than the stock cable WITH the STOCK CHARGER it will not charge at the same rate as it does with the stock cable. More voltage drop for the longer cable and the nexus 7 does not charge at the normal 1500-2000mA rate.
So if you have a charger that has 2A output but the voltage is low ... its not going to charge at all or charge the nexus7 very slowly.
Big battery = lots of amperage at the right voltage to charge it.
I have found that my n7 charges much faster with the provided charger, but my other chargers will charge it... Just not the car charger, but i have a power inverter that i use in the car so it's not really a problem, in my case
I found a set of two chargers - a car charger and a wall charger - listed for the Nexus 7 from a seller on eBay for under $5 including shipping. This is my first post on this forum so I can't include a direct link.
I wasn't expecting too much, but figured for five bucks, I'd give it a try. They shipped quickly and the items were received in good condition. Build quality is 'inexpensive' but seems OK, and both chargers show "Charging (AC)" when in use. Don't know how long either will last, but the price was certainly right!
Last edited by Digital Don; November 24th, 2012 at 03:02 AM.
There are two pins on the host USB port/charger that provides 5V power and another pair used for data - but are also used to indicate that the USB port is enabled for charging, allowing host devices to determine whether or not they will "allow" power to be used for charging while asleep for example. Not all mobile devices bother to check but the Nexus 7 is one of those that do, as is my Motorola Milestone, so neither will charge from a "dumb" charger that has nothing connected to the data lines.
Fortunately it's easy to fix if you're handy with a soldering iron and can get at the back of the socket(s), just connect the two unused data pins together which tells the mobile device that its a dedicated charging port. I've done this for a couple of otherwise useful "universal" battery chargers with USB ports that wouldn't charge some devices, they now work fine.
One final note: some Apple chargers use non-standard voltages on the D+ and D- lines to tie them to Apple devices; these are best left alone. But if the charger has nothing connected to the two middle pins it's perfectly safe to short them together to allow its use with any "standard" device like the Nexus 7.
It's the two middle pins Don. On a computer they are the data pins, on a charger (other than Apple) they are either unused or shorted together. If unused all you need do is short them together. On my "universal" battery charger the USB socket was soldered to a PCB but with no connection to the inner pair of pins (there are only four) so it was dead simple to solder a link across the unused pair to make it work.
Don't touch the outer two connections, they carry the main 5V supply.
This is an interesting read about USB charging standards (or nonstandards in the apple case). As for me, my N7 will charge just fine off my sister's iPod wall adapter bought about two years ago with her iPod touch 4th generation. (it's rated at 5V 1A, and I was using the original cable)