How to Make a 20,000mAh Wireless Touch Power Bank at Home (Using Old Laptop Batteries)

ERGREAT

Introduction

In today’s world, power banks have become a daily necessity. Whether you are traveling, shooting videos, working on-site, or facing frequent power cuts, a reliable power bank can save you from a lot of trouble. But buying a high-capacity power bank is often expensive, and many cheap ones fail to deliver their claimed capacity.

In this project, you will learn how to make a 20,000mAh wireless touch power bank at home using old laptop batteries. These batteries are usually discarded even though many of their cells are still perfectly usable. By reusing them, we not only save money but also reduce electronic waste.

This power bank features a touch-based ON/OFF system, which means there is no physical button to wear out over time. Just touch the panel, and the power bank turns ON or OFF smoothly. The output is stable, efficient, and suitable for charging smartphones, Bluetooth devices, Arduino projects, and any 5V-powered electronics.

I will explain everything step by step in very simple words, exactly how this project is made—from battery selection and safety to enclosure design, wiring, testing, and final assembly.

Components Required -

  • 3D Printed Enclosure
  • Old Laptop Batteries (Flat Type)
  • Power Bank Module (5V Output with Charging Circuit)
  • TTP223 Touch Sensor Module
  • 2N2222A Transistor
  • 100Ω Resistor
  • Connecting Wires
  • Glue Stick / Adhesive
  • Multimeter
  • Soldering Iron & Solder Wire
  • Insulation Tape / Heat Shrink
  • Safety Gloves (Highly Recommended)

Step 1: Designing the 3D Enclosure

The first step of this project is designing a strong and attractive enclosure. For this, I used Fusion 360, which is perfect for precise 3D modeling.
I designed the enclosure in two parts:

  1. Back Body (Black Color) – Holds the batteries and 
  2. Front Panel (White Color) – Contains the touch area, power bank module and output ports

While designing, I carefully considered:

  • Battery size and placement
  • Space for the power bank module
  • Touch sensor mounting position
  • USB output and charging port alignment
  • Proper ventilation and wire routing

A well-designed enclosure not only looks professional but also ensures safety and durability.

Step 2: 3D Printing the Enclosure

Printing both parts separately makes assembly easier and gives a clean finish. After printing, I checked:

  • Fitting accuracy
  • Edge smoothness
  • Port alignment

Minor sanding was done where required to get a perfect fit.

Step 3: Removing Old Laptop Batteries

Now comes the most important and risky part—removing batteries from old laptop battery packs.

⚠ Safety Warning:
Laptop batteries have very sharp metal edges, and improper handling can cause serious injury or short circuits.

Precautions to follow:

  • Wear safety gloves
  • Use plastic tools where possible
  • Never puncture the battery
  • Do not short battery terminals

Carefully open the laptop battery casing and remove the flat lithium-ion cells one by one.

Step 4: Checking Battery Voltage and Health

Not all old batteries are usable, so testing is crucial.
Using a multimeter:

  1. Check the output voltage of each battery
  2. A healthy lithium-ion battery should show around 3.0V to 4.2V
  3. Any battery showing 0V or very low voltage should be discarded
  4. You can try to revive batteries showing voltage below 3.0V

After testing, I selected only working batteries for this project.

Step 5: Separating Batteries into Single Cells

Laptop batteries are often connected in series combinations. For this project:

  • I removed all three connected batteries
  • Separated them into individual 3.7V cells
  • We only need single 3.7V cells, not series-connected ones

This step is important because power bank modules are designed to work with single-cell lithium-ion batteries.

Step 6: Connecting Batteries in Parallel (Increasing mAh)

To achieve 20,000mAh capacity, batteries are connected in parallel.

Why Parallel Connection?

  • Voltage remains 3.7V
  • Capacity (mAh) adds up
  • Provides longer backup time

Steps:

  • Connect all positive terminals together
  • Connect all negative terminals together
  • Ensure strong solder joints
  • Insulate connections properly

After parallel connection, check total voltage—it should still be around 3.7V.

Circuit Diagram -

Step 7: Making the Touch Sensor Control Circuit

This project uses a TTP223 touch sensor to control the power bank module wirelessly.

Circuit Connections:

  • TTP223 GND → Collector of 2N2222A transistor and to GND
  • TTP223 I/O → Base of transistor through 100Ω resistor
  • TTP223 VCC → Power supply VCC
  • Emitter of transistor → In series with power bank module push button
  • Other side of push button → GND

This circuit works like an electronic switch. When you touch the sensor:

  • The transistor activates
  • It simulates a button press
  • The power bank turns ON or OFF

This eliminates mechanical wear and improves reliability.

Step 8: Verifying Circuit Connections

Before final assembly:

  • Double-check all connections
  • Ensure no short circuits
  • Confirm polarity of batteries
  • Test touch sensor response

This step prevents damage and saves time later.

Step 9: Installing Batteries Inside the Enclosure

Now place the parallel-connected 3.7V battery pack inside the back body of the 3D enclosure.
Make sure:

  • Batteries are firmly seated
  • No exposed terminals touch the enclosure
  • Proper insulation is applied

Battery movement can cause short circuits, so fix them securely.

Step 10: Connecting Power Bank Module and Touch Circuit

After placing batteries:

  • Connect battery output to the power bank module
  • Connect touch circuit to the module switch terminals
  • Route wires neatly

At this stage, the complete internal wiring is done.

Step 11: Testing the Power Bank

Before closing the enclosure:

  • Touch the sensor to turn ON the module
  • Connect a mobile phone
  • Check charging speed and stability

The power bank should deliver quick and stable charging.

Step 12: Final Assembly

Once testing is successful:

  • Attach the front panel
  • Use glue stick or adhesive to seal the enclosure
  • Ensure no wires are pinched

⚠ Important:
Short circuits are extremely dangerous with lithium batteries. Always double-check insulation before sealing.

Step 13: Charging and Usage

Now your 20,000mAh wireless touch power bank is ready.

  • Plug it into charging
  • LED indicators show charging status
  • Use it anywhere a 5V power supply is required

In the reference test, a mobile phone was connected and it:

  • Detected fast charging
  • Charged smoothly without heating

Applications of This Power Bank

  • Mobile phone charging
  • Bluetooth speakers
  • Arduino and DIY projects
  • Emergency backup power
  • Travel and outdoor use

Conclusion

This project proves that you don’t need expensive components to build a powerful and reliable power bank. By reusing old laptop batteries, you get high capacity at very low cost, while also helping the environment.

The touch-based wireless control, 3D printed enclosure, and solid battery performance make this project both practical and professional. With proper safety measures and careful assembly, anyone with basic electronics knowledge can build this power bank at home.

ERGREAT

Posted by ERGREAT

Hi, I’m Kishor Kumar — an electronics enthusiast, maker, and traveler from India. I love building DIY electronic projects, experimenting with circuits, creating tutorials, and sharing step-by-step guides that help others learn easily. When I’m not working on electronics, I travel across India with my cameras, capturing stories, places, and experiences that inspire my creativity. Through ERGREAT, my aim is to share practical projects, detailed explanations, and real-life adventures that motivate others to explore technology and the world around them.

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