[GUIDE] PSA: short the data pins to charge your T100 fast with *ANY* USB cable.

[romwell]

First, the problem. The supplied USB charging cable is pretty short, and using a standard USB cable to charge is very slow: T100 trickle-charges, which takes forever. So, if you want to use a longer cable, or lose your charger and buy a generic one, charging time grows from 3 hours to more than 12. This has been identified as a "con" in reviews, and I could not find a solution easily on this forum.

Now, the solution. Some people on this forum know about it, but I haven't seen any detailed instructions, and when I had this problem I couldn't find the solution here. This post is to remedy this for other people in the same situation.

Basically, T100 distinguishes between a charging cable and a normal (data) USB cable. When charging over the normal cable, T100 conforms to the USB spec, which limits the current to 0.5A. In my tests, it draws about 0.34A (I used a USB power meter).

To use more than that, you need¹ to use a charging cable. The only difference between the two is that the charging cable cannot be used for data, and has the data pins shortened on the device side to indicate that.

So, if you are using a non-Asus supplied cable, and your charging is painfully slow, here is what you can do:

• Method 1: non-invasive. Pick a piece of tape and aluminum foil, and stick the foil onto the middle two pins on the large USB plug, shorting them. Voila! The device now draws about 1.5A of current, and charges about as fast as with the original cable.
  
  The method is described in full detail here. I'll just include the pictures from that post:
  
  IMG_20111022_191756.jpg IMG_20111022_191835.jpg
  
  
• Method 2: invasive. Cut open the insulation on the USB cable. Inside, you will see 4 wire: red, black, white, green. Red and black are used for power, do not touch them.
  
  jRasn.png
  
  Cut the white and green cables and remove the insulation from the ends. Now short (twist together or solder) the white and green cables on the device side, i.e. on the part of the cable that goes to the mini-USB plug. Insulate everything
  with copious amounts of electric tape, and you're done.
  
  
  

I have been using both methods: Method 1 works well when you need a quick fix and don't plan to plug/unplug the cable many times. Method 2 is what I currently have, and is much more robust.

I'll post more pictures here if I do this with another cable, but overall it's a fairly simple procedure that doesn't require any soldering.

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¹_{I don't know whether the original ASUS cable was like that, or if they have other means to indicate that the cable can be used for charging, as I have lost it.}

[GPz1100]

Somehow my original post went to null. Below is a vague recollection.

=====================

On android devices, the charging rate/method (data rate .5A or ac rate 1A) can be identified through software. Is there a similar utility for windows that reports this info.

I would expect the charger used to determine what sets the charge rate. My Galaxy S4 uses a 2A charger similar as what's included with the T100t(am). Will try charging using that charger and generic data cable and report back.

=====================

Ok, so there is a tool to determine charge rate - BatteryInfoView . Lookin the charge/discharge rate row. The quantity is expressed in terms of mWh. This is easily converted to Ah by dividing the number by 5V.

I tested several configurations on my T100TAM (bios 205)

asus cable/charger ~ 3300 mW = 660 mA
asus cable/galaxy s4 charger ~3000 mW = 600mA

galaxy cable/asus charger ~3200 mW = 640 mA
galaxy cable/galaxy charger ~3100 mW = 620 mA

Although these numbers vary, I attribute it to the measuring method of the software. These values were of course obtained with the unit power on and screen on.

I then closed the screen, connected via remote desktop to observe values. It appears the unit does not entire sleep immediately at screen closure but rather some short time later. A few generic usb cables were also test with similar results to above

Testing similar combinations as above, the charge rate measured in at ~5000-5300 mWh = 1000mA to 1060mA. Again, both chargers are rated at 2A. A more proper test would be to conduct tests using my kill-a-watt meter that measure draw at the connection to the AC line.

Either way, with the cables used here, the charge rate is faster than what would be expected from a computer/data cable usb connection.

For anyone posting their own results, please identify the exact device model and bios version.

[Tavero]

Hi there,
A few day ago my T100 fell from my desk while loading. Thankfully the tablet itself is unharmed, but the Micro USB plug was ripped apart. I have the Power Adapter version with the fixed power chord.
Because I am skilled in repairing stuff (well at least I know how to hold a soldering iron without burning myself too often) I thought I could repar it in 15mins.
So I cut the plug from an old usb data cable and connected the VCC and GND cables.

I was semi sucessfull. While the new powerchord is working and charging while the T100 is shut off, it cant deliver enough current to charge it while running. It seems the new power chord can only deliver 500 - 1000 mAh.

I have two theories:

1. I've read in other Forums that ASUS is also connecting data+ with VCC and data- with GND on the micro usb plug, to have four connections instead of two. Could a kind soul check the voltage or resistance (if voltage is 0) between the data+ and data- connection with a Multimeter? Its the 2nd and 3rd pin.
micro_usb.jpg

2. The wires of a regular USB 2.0 cable are just too thin to deliver the required 3000 mAh. Im working on that. A new plug without wires is already ordered.

best regards Tav

[Tavero]

Hi again,
I found the guide from romwell a few posts below mine, who suggests to connect data+ and data- with each other.
So Ive tried it and now it works. Loading with 1500mAh or more.
Thank you romwell

[janner43]

Thanks for taking the time to post these guides, guys.

I have merged your two threads together and stuck the thread to make it easier for others to find.

[stokking]

Hmmm, I thought this fixed my issue, but apparently it did not. I have my original charger and cable, but it only trickle charges now on my TF701. Sometimes it does charge fast, but many times it does not indicate charging and it only charges very slowly.

Any ideas here? I bought a replacement cable, as I thought it was the cable. The new cable worked for some time, but started working less well this week.

I just now tried this aluminium folie trick with my Anker charger, and it did started charging right away, but stopped just a bit later. It is really annoying, this problem. Any ideas? I might as well cut the wires of my new cable, as it doesn't work as a data connection cable anyway for linking my tablet to the computer.

[Ventricle]

Hi there,
A few day ago my T100 fell from my desk while loading. Thankfully the tablet itself is unharmed, but the Micro USB plug was ripped apart. I have the Power Adapter version with the fixed power chord.
Because I am skilled in repairing stuff (well at least I know how to hold a soldering iron without burning myself too often) I thought I could repar it in 15mins.
So I cut the plug from an old usb data cable and connected the VCC and GND cables.

I was semi sucessfull. While the new powerchord is working and charging while the T100 is shut off, it cant deliver enough current to charge it while running. It seems the new power chord can only deliver 500 - 1000 mAh.

I have two theories:

1. I've read in other Forums that ASUS is also connecting data+ with VCC and data- with GND on the micro usb plug, to have four connections instead of two. Could a kind soul check the voltage or resistance (if voltage is 0) between the data+ and data- connection with a Multimeter? Its the 2nd and 3rd pin.
micro_usb.jpg

2. The wires of a regular USB 2.0 cable are just too thin to deliver the required 3000 mAh. Im working on that. A new plug without wires is already ordered.

best regards Tav

Any updates on that?

I've checked if shorting data pins on micro usb connector changes anything and it doesnt in my case.
I have the latest bios version.

UPDATE:
It does work, but my power management integrated circuit was broken and that's why it didn't work before - after fixing PMIC, it's working as long as I have thick wires.

[Ventricle]

UPDATED whole post because it was misguiding.

Here are pictures of the Micro USB connector of the NON-DETACHABLE power cable of the OEM EUROPEAN power adapter 5V/3A PHIHONG PSAC15R-050 (soldering areas ripped out ;/ )





This is another image I made for myself as a cheatsheet when I was trying to figure this crap out.



What I read from the picture:

Asus is BAD - they've added a resistor shorting the 4th and 5th PIN of the connector(ID -> GND) with a 30C SMD resistor (20kOhm). This resistor is what makes the charger unique so we wouldn't try buying a non-genuine charger.

I have it all sorted out and I'm preparing a GUIDE for the whole thing. Stay tuned.

[Ventricle]

This post included misguiding information, because my PMIC (power management integratec circuit) broke and this all lead me to confusing stuff. Once the PMIC was fixed, I could make my own cable just fine.

[N00dle]

Sorry for the massive bump. I am travelling long term, currently in rural Colombia. My charging cable gave up on me

I have a few questions...

As stated by OP, the charging cable is not a data cable, beause it is wired differently. However, I was always able to use my charging cable as a data cable too, while charging fast as well... So what's up with that??

Secondly, I have one other Micro USB cable, but I do not want to fuck that up. Plus, as mentioned elsewhere, maybe the wires are too thin to deliver enough amps. So there's that too.

In the Netherlands, where I'm from, they sell special "charging" usb cables. Does anyone have any experience with those? If so, I may be able to travel down to Medellin and buy one of those.

Does anyone have any other experiences to share?