proprietary USB charger???

[PressureDrop]

so I have 4 of these (2 branded as "Monoprice" and 2 as "XTG Technology")

and according to the specs they have 2.1a USB output

They charge our iPods, RAZRs, DROID 4, and pretty much every USB item in the house except the Nexus 7
no wait !

WTF? My Motorola chargers for my RAZRs charge it, and obviously the charger that came with it charges it, but these that I have around my house do not!

 

[netnerdvana]

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.

 

[jova33]

I will put that in my rucksack.

Hmmmm.... 11B wouldn't put that in his ruck..... I'd never heard the term rucksack outside of the military.

Anyways, on topic, I use my wife's three year old BlackBerry charger. Works fine. If using it while in use it won't charge, but the battery won't drain.

 

[Lordvincent 90]

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

 

[sleezecheeze]

I've used a samsung charger and HTC charger on my nexus 7. No adverse effect so far.

 

[PressureDrop]

I want a slim, multi charger that I can use to charge several devices at the same time though! That was the point of the wall plates and this thing (none of which charge the Nexus 7! )

 

[PressureDrop]

I want a slim, multi charger that I can use to charge several devices at the same time though! That was the point of the wall plates and this thing (none of which charge the Nexus 7! )

so I tried out this and found that it, like everything else so far, does not charge the Nexus 7 GRRRRRRR!

 

[PressureDrop]

I am starting to regret that I did not get a Samsung Galaxy Tab

 

[Digital Don]

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!

Don

 

[John Bean]

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.

 

[Digital Don]

Thanks for that information, John!

Do you have a picture or diagram you could share so we know which pins need to be connected?

Don

 

[John Bean]

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.

 

[Digital Don]

Thanks John. Only two wires... even I could do that!

Don

 

[alisonc]

MintyBoost - The mysteries of Apple device charging

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)

 

[wtherrell]

Bought a couple of "charge -only " cables. Have worked with any charger I have tried --even a 500mA one. Solved all my charging problems.

 

[John Bean]

Bought a couple of "charge -only " cables. Have worked with any charger I have tried --even a 500mA one. Solved all my charging problems.

That's a good idea - putting the "short" in the cable itself. I didn't know they existed.

Better though if the makers of generic USB chargers bothered to comply with the charging spec that's been around for years.