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Usb charge

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EyeTech

Senior Member
May 6, 2010
177
18
Manchester
I too had been struggling with charging with other sources until I built an adaptor as described above. I found the resistors were necessary for me. 2 pics attached.

d92bbd25-d4dd-f650.jpg

d92bbd25-d50e-7d57.jpg


Sent from my GT-P1000 using XDA App
 

shoe3rd

New member
Dec 8, 2008
1
0
ipad charger compatibility?

I was just wondering if anyone tried an AC/USB ipad charger with the proper cable to charge the Galaxy Tab.
If the products that are sold on dealextreme or ebay charge properly an ipad, and if the same usb trick is necessary to charge the ipad and the gtab, then it should charge the gtab properly.
Am I wrong?
 

annafil

Member
Jul 24, 2010
34
0
Singapore
iPad charger doesn't work, unfortunately.

But I picked up a 2000mA usb universal charger at a local gadget shop, and a third party Tab cable, and even though the icon doesn't indicate charge, the battery level goes up instead of down, albeit slowly so I'm happy for now :)
 

agentdr8

Senior Member
Mar 4, 2007
3,644
1,885
Cowtown, CA
It charges via USB, but slowly. The OEM 2A charger has different voltages on the data lines that tell the tab to initiate a fast charge at a higher current draw. This is similar to how the iPad chargers work, and why building the usb adapter in this thread helps when charging via non OEM chargers (including USB ports).
 

doloop

Senior Member
Nov 13, 2007
169
18
It charges via USB, but slowly. The OEM 2A charger has different voltages on the data lines that tell the tab to initiate a fast charge at a higher current draw. This is similar to how the iPad chargers work, and why building the usb adapter in this thread helps when charging via non OEM chargers (including USB ports).

Reminds me about hd2 kernel developpement discussion: like on our tabs, i think the kernel was responsible for choosing charging rate, because some kernels with bugs were keeping slow charge mode whatever the supply was.

On non buggy kernels, it seems the trigger was connection of data lines: a computer does connect data lines -> slow charge, a wall charger does not -> fast charge.

As soon as will have custom kernels for our tabs, we'll be able to change the charge mode that the tab choose. Some computer have powerfull usb power line. However some low quality usb car power adapter could get destroyed if our tab use fast charge mode for too long.
 

Coolsaber57

Senior Member
Jan 8, 2010
272
12
Ok, I'm a little confused as to how this is supposed to go when soldering the resistors.

Can someone clarify which version is correct? I'm leaning toward the one on the right, but I want to be sure.

wiring.jpg
 

Coolsaber57

Senior Member
Jan 8, 2010
272
12
It works!

Following the instructions (and the diagram I made) I was finally able to get the tab to charge via USB.

I had an old crappy 1ft extension cable lying around, so my first 2 attempts used that. They failed due to the wires being too small to easily strip and too weak to hold together while soldering.

I went to the store and grabbed a thicker looking cable and tried 1 more time and voila! Charging.

One piece of advice to anyone doing this: use a razorblade to strip the wires vs. a wire stripper. They are really small and the coating is very much molded around the copper wire, making a wire stripper difficult to use without ripping half of the wires out.

Thanks again to everyone in this thread!
 

ajayendra

Senior Member
Jun 20, 2008
316
8
Houston, TX
Wow this is so cool!

Tried this and now the GT is charging and charging FAST, even with 1000mA charger. I made one USB juction what has been in discussion which worked great and then I opened up a $0.69 usb charger (1000mA), soldered the resistors right on the board and voila!...

Thanks a lot!
 

wirelezzz

Senior Member
Jun 14, 2007
272
48
GTA
nice

im going to make an adapter for mine today , i have a nice huge electronic deparment beside me where i can buy lots of this components. ill make a couple to have laying arround lol.
 

wirelezzz

Senior Member
Jun 14, 2007
272
48
GTA
got my parts and ready to build some adapters

time to go to work , ill make a few of these to have laying arround
 
Last edited:

mingkee

Senior Member
I was led to this thread about USB charging solution. Now I have a object. You need:
  • a PCB (generic from ratshak or you can print and etch)
  • an A-type USB female jack
  • a miniUSB jack (SMT type is OK)
  • a 10k ohm resistor
  • a 33k ohm resistor

When assembling, make sure you're clear pos and neg and solder everthing on the PCB. Additional solder may be required on miniUSB jack to reinforce it.

edit:
I made a draft one.
180499_10150407307660711_571875710_17377228_77494_n.jpg

167148_10150407305800711_571875710_17377207_6310342_n.jpg
 
Last edited:

everunman

Member
Sep 19, 2010
12
0
Melbourne
Can I buy that adaptor somewhere ? Ebay e.g. ?

confirming those who dont want to make their own charge adapter can buy this one on ebay, it works great, can charge from usb or other usb portable chargers

edit cant post a link as im not at 8 posts but search ebay for

Adapter für Samsung Galaxy Tab - USB auf USB Adapter
 

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  • 11
    Hi. I've solved the problem of using other chargers with GT.
    Like Apple, Samsung used a little trick with their chargers.
    To charge your GT with any usb charger you have to make a little adapter.

    Usb pinout:
    gnd d- d+ 5v

    To work you must short d+ and d-.
    From 5v use a 33k resistor to d+/d-.
    From gnd use a 10k resistor to d+/d-.
    If you have multimeter you should obtain ~4v between 5v and d+/d-; and ~1v between gnd and d+/d-.
    I tested it and it's working.
    2
    I've tested with d-/d+ shorted and it's not working.

    @MizGarfield if u have 1 usb extension cable u can cut it on half.
    Tie together white and green wires.
    Tie black wires and conected to that 1 end of 10kohm resistor, the other end tie it to green/white wire.
    Same to red wires but use 33kohm resistor.

    See att. Sry for drawing.


    You don't need that for modern devices has i told you. It did not work because you did it wrong. I have all my usb chargers working the new way, you even have wikipedia talking about it. You have to cut the data + and - on the power supply from the female usb port and short only the female d+ and d-. Trust me it works and it is alot simpler.

    Edit : from wikipedia "The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200 Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured. The increased current (faster, 9 W charging) will occur once both the host/hub and devices support the new charging specification."

    ""As of June 14, 2007, all new mobile phones applying for a license in China are required to use the USB port as a power port.[35][36] This was the first standard to use the convention of shorting D+ and D-.[37]""


    http://apple.slashdot.org/story/10/08/03/1743240/Hardware-Hackers-Reveal-Apples-Charger-Secrets

    ""We all love to call out Apple when they design deliberate incompatibility into their devices, but there is a perfectly valid technical reason for what Apple is doing here, and, in fact, they are following a USB specification (which LadyAda unfortunaterly didn't even test).

    Without data communications or when suspended, devices may legally draw no more than 2.5mA from a host, which is useless for charging. In fact, even if you're generous and pretend they're connected, devices are not allowed to draw more than 100mA without negotiating for a higher current, which requires actually talking to the host, and 100mA is still too little to charge properly. 500mA is the maximum allowed by the USB spec, but devices must negotiate it (there may be too many devices on the bus for negotiation to succeed).

    Before there was a spec for "dumb" USB chargers, Apple used the resistors as a sentinel to avoid drawing too much current from undersized chargers in order to avoid damaging the host. This is a hack, but it works, and honestly, we're smart enough to figure out a couple resistors on the data lines. It's not like they're using crypto auth on the charger. They have a perfectly valid reason to do this. Devices which charge from "dumb" chargers aren't following the spec, though this is a common industry practice.

    As it turns out, the USB-IF came up with a USB Battery Charging spec [usb.org]. The spec is long and boring, but it boils down to: short together the data lines (no resistors required) and you indicate that you're a dumb charger that can supply anywhere from 0.5A to 1.5A.

    Guess what happens when you short the data lines of an iPhone 3G and supply 5V [marcansoft.com]. Did Apple just follow a standard? Incredible!

    (Yes, I'm not following the USB spec there by in turn using a USB cable to supply the 5V and not negotiating over its data lines. I didn't feel like grabbing a dedicated 5V PSU for the shot, so sue me.)"""

    http://marcansoft.com/transf/iphonechg.jpg

    ok ??? :D no need for resistors, only 5.3V MAX and d+ and d- shorted
    2
    but smt is wrong on your custom setup, voltage ??

    EDIT: i just measure the original charger and it has no resistance between the data and power pins.

    I think i know what could be wrong, when you plug in the Tab and it says not charging, how many volts have you got at that time ?

    The original charger is very good because when it not charging the tab it has 5.3x volts but when you plug it in it lowers to 4.8x V Max and that is very good ! most chargers tend to lower much more (bad quality or just not powerful enough) and that is what causes the not charging messages on the tab or other devices.

    Well i rest my case on this.
    1
    Hi. I've solved the problem of using other chargers with GT.
    Like Apple, Samsung used a little trick with their chargers.
    To charge your GT with any usb charger you have to make a little adapter.

    Usb pinout:
    gnd d- d+ 5v

    To work you must short d+ and d-.
    From 5v use a 33k resistor to d+/d-.
    From gnd use a 10k resistor to d+/d-.
    If you have multimeter you should obtain ~4v between 5v and d+/d-; and ~1v between gnd and d+/d-.
    I tested it and it's working.
    To charge your GT with any usb charger you have to make a little adapter.

    How can you do that? You need an extra device adapter? Please explain.
    1
    USB Charger

    This is what worked for me.

    Items Needed:

    USB Extension Cable
    33k-Ohm Resistor (Shack Part No. 271-1129)
    10k-Ohm Resistor (Shack Part No. 271-006)

    Steps:

    1. Cut USB Extension Cable in half, lets name the 2 halves, the half you will plug into the power suppy will be called "Cable A" and the half that you plug into the Galaxy Tab Data Cable will be called "Cable B"

    2. On 'Cable A" strip outer plastic to expose all wires within, eliminate Green and White on this cable only as it will not be needed, leaving you with only the Red and the Black Cables

    3. On "Cable B" strip outer plastic to expose all wires within, this should leave you exposing all 4 wires

    4. On "Cable B" strip both the Green and White wires and join thes 2 wires with the 2 resistor ends (you should be using the resistor ends that have the red band with these wires), these can be joined by either soldering or just twisting together.

    5. Strip Red wire from both cables and join together with the 33k-Ohm Resister (this will be the larger of the 2 resistors and should also be the end with the Gold Band) and as well join these together with solder or just twisting together.

    6. Repeat the above process with the Black wires and 10K-Ohm Resistor.

    7. No finally use Electrical Tape or Shrink Tubing to cover all your work.

    This worked using it on a Champtek 5v 2.1a USB Car Charger and Home Charger. Also worked with iPhone charger. Also works with Original Galaxy Tab.

    Hope this helps out.