Currently i am using Samsung Galaxy Tab, model is GT-P1000, to test my application, so i usually attach it with PC through USB cable and it is attached for a whole day though it is showing low battery at the end of day. but it should charge the battery same as the other phone when we attach it with USB.

Does anybody know, what may be the problem why my samsung galaxy tab is not being charged through USB cable?

  • 1
    @ PM - Paresh Mayani: Are you connected directly to the PC, or via an USB hub ?
    – Edelcom
    Commented May 20, 2011 at 6:15
  • @Edelcom Thanx for your reply. FYI, i am not connected but my tab is..and tab is directly connected using USB Cable. Commented May 20, 2011 at 6:35
  • 1
    @ PM - Paresh Mayani: Did you try another cable ? I had a similar problem once, which went away simply by choosing another cable. I gave this answer to one of the other questions here in the forum and that guy too had to change the usb cable.
    – Edelcom
    Commented May 20, 2011 at 6:40
  • @PareshMayani i have face same issue...
    – parag
    Commented Apr 16, 2012 at 9:22
  • @PareshMayani i have one issue related Tablet stackoverflow.com/questions/10161232/…
    – parag
    Commented Apr 16, 2012 at 9:23

11 Answers 11


Tablets have larger batteries than phones and may be unable to sufficiently charge from the half amp limit of a USB port, especially while they are fully on (screen on and full speed processor clock).

Some will barely charge if the screen is off but come with high current 5v "usb-like" wall chargers, others use a higher voltage charger on a custom connector - typically something round. Sometimes the "usb-like" ones are actually special cables with extra pins that tell the tablet that a special high-current charger is being used.

Check your user manual, or try the supplied charger.


The Samsung Galaxy Tab has a loading current of 2 A, but the USB-Specificication only allows 500 mA for the whole bus.

With this in mind, it should be clearly visible why the SGT isn't charging via USB.

At least that is true for the original Samsung firmware.

If you are able to install custom ROMs you will probably get fast-charge-support, with this activated your tab will even charge over USB, but it will take much more time than with the AC-power-adaptor.


The best way to get Galaxy Tab charge from USB connection to PC is to turn it off. This way it charges, and shows charging, it just takes time because the power available on USB is limited.


The galaxy tab GT-P1000 can use more power in operation than it can draw from an USB port. If this is the case, the battery will eventually run out. This is especially likely if your GT-P1000 is doing a lot of battery consuming things, such as WiFi, GPS, high CPU loads, or having the Screen on all the time. Your mileage will also vary depending on the USB port, as different USB cards can supply different power levels (the default spec is less than what the GT-P1000 usually draws; though nobody to blame here).

E.g. for me typically using WiFi, no GPS, screen always on, hardly any CPU load and connected to a Dell Latitude Laptop, my tab will de-charge about 2% per hour. If I turn the screen off it will actually recharge, although slower than with the Samsung wall-plug.


Does it just display not charging or is it really not charging?

My Galaxy Tab also shows not charging when plugged in to the notebook's USB port. But after a couple of hours (much longer than with the charger), it is full charged.

Over at the Apple sister site there is an explanation why the iPad displays not charging; I guess this applies to Android devices as well:

If you could see the screen while the iPad was asleep, it might even display the charging icon. It’s the modern-day “Does the refrigerator light stay on when I close the door?” mystery.

There is another answer that explains why charging is slower on a computers USB port than when connected to the charger itself.


I don't think it's only because of max current problem. I tried whole bunch of power adapters having 2~3 amps. But failed to have a symbol charging. I don't there is anybody who succeeded in having the charging symbol with home made charger, but I think the genuine charger would have special signal through usb data pins or even thtough the + pin. Like other laptop batteries whatever. It means samsung doesn't want users to use their cheap and plentiful ones as spare at home.


The problem is the device is looking for specific resistance on certain pins. Without these the tablet won't try and draw the full power.


This is easy!

Problem is the cable. This should be AWG28/1P+AWG20/2C -cable, if you will charge you tablet by 2A power. If the /2C is over AWG20, etc. AWG28, the resistance in the cable is so high that the voltage will drop under 4V on the other end of the cable. You should also buy a short cable, so the resistance won't be so high. The gauge AWGxx tells the copper wire's diameter.

Other possibility is, that you buy a 2A charger with 6V voltage. By that way you may charge you application by 5V and 2A current even through a cheap usb cable.


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.


Brother,Samsung has designed its tabs in such a way that it can not do charging and data transfer computer/laptop for battery protection at the same time.If you want to charge your Tabs,then simply switch off your tab and connect data cable.your Tab start getting charged.

  • This is not Samsung's design, it's a limitation of USB 2.0. Devices can request over 500mA only if their data pins are unused and shorted. This is why the Tab doesn't charge quickly from USB. Commented Oct 23, 2014 at 6:46

LOL just plug in to PC USB and swish off your TAB he will shut down data transfer and will start charge To see if it charging just clicks switch and it will show on screen battery charge icon

P.S. u don't need any adapters


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