Introduction: Smartphone With External Battery (Hacked Mobile)

For long time ago, a friend gave me a damaged smartphone which wifi card was burned out and battery was almost dead. The fact is that the rest of the mobile phone worked just fine so I planned to use it as a lab tool for testing different things with some APP and sensors included in the mobile phone.

So I only had to "repair" the battery, because I didn't care about the wifi module, it would be expensive to repair and I didn't need it.

As spare parts for this mobile phone are too expensive, I rejected the possibility to replace the battery, so I will add an external battery (or power supply) connector in order to power it up.

This gonna be a short and fast post with a basic explanation of what I have done. Any question or comment would be appreciated.


For this project I will only need:

  • The mobile phone
  • Some cables
  • A battery

And also I will need some tools:

  • Screwdriver kit
  • Disassemble kit (for open the case)
  • Soldering Iron (e.g. from my first post)
  • Power supply (for test the result)

Step 1: Open the Case and Access the Battery

Firstly we need to open up the case in order to access the integrated battery. As this battery has its own connector below some shielding, I have to remove them before we can remove the battery.

Below those shields, there is the battery connector.

Step 2: Extract the Battery From the Chassis

The connector can be easily unplugged levering it with a screw driver. Then is time of remove the battery.

As you can see in images, my battery got really damaged when I was removing it. It looks like was in a middle of a war.

WARNING: due to the high adhesion glue used to fix the battery in the chassis, you will have to apply to much force into the battery in order to detach it. In some cases, you could harm the battery, bend it or even puncture it which can result into a battery explosion and fire.

Please, before remove the battery, discharge it completely (I mean to 0% energy, not 0V) so you can avoid explosions in case you damage it.

Step 3: Prepare Battery Connector

Now we need to connect some wires to the power input of the phone, but using a soldering iron in the motherboard is a risky task I didn't want to take, so as I would not use the damaged battery anymore, I decided to use its own connector.

So I cut it and planned how to solder some cables to it. I had to remove the flex isolation layer until copper was exposed. Then, using soldering flux and tin, I managed to solder a pair of wires with the correct color for their polarity.

NOTE: You can check which lane is negative by using a multi-meter in continuity mode, and test which lane has continuity with metal shielding. As metal shielding is used to block EM radiation, those have to be connected directly with ground, so here you have your reference point to test.

Step 4: Test the Connector

Now we have a connector which fits great and with two cables to power it up.

Also, in order to put the NFC antenna correctly, I used an EVA block with the same thickness as the original battery to attached to it.

Step 5: Modify the Chassis

Next step, is to make a hole to the aluminium chassis so you can pass the cables through it.

For this work you can use an abrasive file, but I used a die grinder with a metal file on it.

But the back cover is still not closing.

Step 6: Modify the Cover

What we did on the chassis, now is time to do it in the cover too. I simply grind a little hole so both cables now pass through the case perfectly and back cover can be closed.

Step 7: Reassemble Mobile Phone

Now everything is fitting, we need to reassemble the phone components and shieldings in order to test if the hack works.

Remember to put every shielding before powering up the mobile so you avoid any chance of damaging the circuits.

Step 8: Powering Test

Finally, we can test if it works or not. We turn on the power supply, adjust the voltaje (and OCP in case something goes wrong), connect the wires and turn on the output.

WARNING: Remember that you are powering up te phone through the battery port, so you must simulate the battery voltaje. That means that a Li-Po battery voltage can go from 3.2V to 4.1V maximum. Any over-voltage can damage the phone irreversibly.

As you can see, the phone is working perfectly and with 3.9V, the battery monitor is indicating 40% of charge.

And here you have a mobile with an external powering.

Step 9: Extra Features

Once it's correctly working, you can improve the design adding silicone to the hole where the cables exit.

This will seal that hole in order to avoid dust or water to enter inside the system and fried it. The con is that this will glue the case with the chassis and, in order to open up the case, you will need to break the seal. But if you don't plan to open it, will be a nice solution.

Finally, to the outgoing cables you can attach directly a Li-Po or Li-Ion battery with only one serial cell (3.7 Nominal Volts) and you could use it as a portable device again and you could still charging that battery using the micro USB of the phone and its charger.

For example, I can use this huge 11000 mAh battery which will give me a long time of portable operation.

I hope you enjoyed and found this instructable interesting. I will appreciate any comment.
Have a nice day!!