Permanent battery + USB connection for Tablet


Nov 15, 2012
Hello Everyone,

I am new here and wasn't sure where to place this post. If Admins believe Hacks or Usage sections to be more appropriate for it - please move the post.

Now to the point:

I've got two Samsung Galaxy Tab 7.0 tablets - old one and a new one.
I keep them employed for up to 10 hours a day. The obvious problem is battery - it doesn't last long enough under heavy load.
The simplest solution is, of course, to keep them constantly plugged-in to the charger.
The catch - I need them connected to the USB at all times (primarily for development and wired resource management).
USB port provides only 500mA, so they don't charge - they just discharge a little slower than when unplugged.

It is incredibly inefficient to disconnect the device from USB, charge it, and connect it again.

Therefore – I’d like to hack it a little. Or mod it, if it's a better word. I’m not concerned with hardware warranty, at this point (I’ll be experimenting on the old one first, and it’s long past its prime).

What I need:

I want to have the device operating 24/7, constantly connected both to the charger and to the USB port on my PC.

How I imagine doing it:

I take two USB cables. I connect one (A cable) normally to PC USB and to the tablet. I cut the second cable (B cable), remove the tablet plug. I connect the wires from the B cable directly to the battery wires, and plug the other end of the B cable to the charger – this way the battery is always being charged directly from the charger, and tablet port is used for USB connection.

Doubts and questions:

1) Will it work? Has anyone tried anything like it?
2) What is the blue wire running from the battery for? Is it for the thermistor? Do I need to worry about it at all?

3) There are two black wires, two red ones. Which ones should I connect the respective battery charger's wires to? To all or just some set of two of them?

Link to the picture of the insides:

4) Better yet – can I simply dump the battery and connect the charger directly to the battery socket wires?

I’m quite determined to go ahead with it, and I could use any help and advice you may have for me. Also, I’d like not to kill the tablet, or myself for that matter.

Any guidance is very welcome.
Thank you.


Nov 12, 2012
the samsung batt. is in parallel, if you can charge on usb, you are running 4.7v.

use a regulated 5V DC external power supply and solder it on any of the black terminal the same on the positive side.
using the charger is a bad idea, you need the same or higher amphere as your battery.

you are right, the blue one is the thermal sensor which stops the battery from over cooking =)