DIY Power Capsule: a Compact and Customizable Charging Solution

Introducing the Power Capsule, a handy little gadget designed to keep your devices charged while you’re on the go. This compact device packs a powerful punch with just a single 18650 battery and a 5V step-up power module. It fits snugly into a 3D-printed casing made up of a battery housing, a module housing, and a capsule, making it small enough to slip into your pocket.

But it’s not just practical—it’s also stylish. You can choose from a variety of colors to make your Power Capsule truly your own. Whether you’re traveling, at work, or just out and about, this power capsule is designed to be both functional and personalized, making it a great fit for the Rainbow contest. Finally, the moment had arrived! Lets began.

1* 3.7v 18650 Li-ion Battery 2200mAh (or 2600mAh): The core power source for the capsule, the higher the battery capacity the better it is.

1* 5V USB Step-Up Power Bank Charging Module with Charging Protection (134N3P): Converts the battery's voltage to a fixed 5V output for charging devices.

2* PVC Wires 22awg (10cm) [Red, Black]: To connect the battery and the USB step-up power bank charging module.

3D Printer and Filament: This is used to create the capsule’s casing. Use your preferred filament color.

Soldering Iron and Solder: Essential tools for connecting the electronic components.

Soldering Accessories: Includes flux and solder wire for effective soldering.

Digital Multi-Meter: To test and ensure the circuit is functioning correctly.

The casing is constructed in a 3-piece assembly to keep the project simple and functional, with each part playing a crucial role. I designed the parts in Autodesk Fusion 360, but you can use any CAD software or the provided STL files for your convenience.

• Battery housing: This part houses the 18650 battery and includes a cutout for the battery wire. It ensures the battery is securely held in place.
• Module housing: This cap is designed to hold the 5V step-up USB charging module. The provided slots allow the module to fit snugly and stay secure.
• Capsule: Connecting both the battery and module housings, the tube acts as the main body of the capsule, covering and protecting the internal components. It's fully customizable in terms of color, allowing you to personalize it according to your preferred look and style.

I have provided the STL files for 3D printing all the parts, given below.

The next step is 3D printing, where your designs come to life. A calibrated printer is crucial for achieving quality results, so ensure your printer is fully calibrated before starting. Use the following print settings for each part:

• Layer Height: 0.2mm (finer layers offer better detail)
• Nozzle Temperature: 230°C
• Hotbed Temperature: 60°C
• Print Speed: 50mm/s (slower speeds can improve print quality)
• Material: PLA+ (for high-quality prints)
• Infill Percentage: 100%

These settings apply to all three parts of the capsule. For personalization, you can choose any color you like. The recommended color combination is:

• Module housing: Black
• Battery housing: Black
• Capsule: Any color (bright colors will look great)

The circuit is simple. Connect the +ve terminal of the battery to the +ve terminal of the module, and the -ve terminal of the battery to the -ve terminal of the module. Refer to the circuit diagram for visual guidance.

You can also use the type-C 5V USB Step-Up Power power bank charging Module with charging protection (134N3P) module instead of the common type-B module (I have this type-B module sitting around my home, which I have used in this project).

Description: (some technical information)

5V USB Step-Up Power power bank charging Module with charging protection (134N3P)

• 1A (Approx) Power Bank Module
• Support Single Cell Lithium Battery, including Lipo and Li-ion
• Support 18650 and 14500 Li-ion battery
• Charging and discharging indication
• Charging: RED LED Blink fast
• Full Charge: RED LED Blink Slow
• Internally installed charging and discharging power MOS
• Preset 4.2V charging voltage, precision ±1%
• Max 8uA standby current
• Integration charging management and discharging management
• Intelligent temperature control and overtemperature protection
• Integration output overvoltage protection, short circuit protection, overload protection
• Integration overcharging and over-discharging protection
• Support trickle mode and zero voltage charging
• Supply Voltage: 3.7V~5.5VDC
• Maximum Charging Current: 1A (max)
• Output Discharge Voltage (Boost): 5VDC (Approx)
• Maximum Discharge Current: 1A
• Battery Cutoff Discharge Voltage: 2.9V
• Discharging Efficiency: 85%
• Dimension: 23mm x 18mm x 10mm
• Weight: 3gm

1. Prepare: Clean the terminals of the battery and module, and strip the wires in appropriate length.
2. Heat Iron: Set your soldering iron to 350°C (662°F).
3. Solder Positive Terminal: Heat and apply solder to the +ve terminals of both the battery and the module. Let cool. (Pro tip- Scrach the battery terminals using some sharp object and then apply the flux and solder it, this helps in providing the grip to the solder)
4. Solder Negative Terminal: Repeat for the -ve terminals.
5. Check: Use a multimeter in the continuity mode to ensure a solid connection.

1. Check Output voltage: Set your multimeter to the DC voltage measurement range and connect the test leads to the output pins of the USB port (refer to the circuit diagram for pin locations). The reading should be close to 5V. If it shows no voltage or less than 5V, proceed to troubleshooting (point 2).
2. Troubleshooting: Inspect the soldered joints and wires to ensure there are no loose connections or shorts. If the battery or module is heating up more than expected, it may indicate a short circuit inside.
3. Test Device: Connect a small electronic device to the USB output to confirm that it charges the device properly.

1. Insert the Battery: Place the 18650 battery into the battery housing and align it over the cutout for the battery wire.
2. Assemble the Battery housing: Insert the Battery housing with the battery into the capsule, ensuring it fits securely.
3. Connect the Module: Position the 5V step-up power module into the module housing, ensuring it fits snugly into the provided slots.
4. Assemble the Capsule: Align the module housing with the capsule and gently slide it over to connect them, ensuring a secure fit.
5. Final Check: Ensure all parts are properly aligned and firmly connected. If necessary, use adhesive to secure any loose parts. Verify that the power capsule is sturdy and the USB port is easily accessible.

Awesome job on finishing your power capsule! It’s a handy little gadget that’s perfect for keeping your devices charged. The customizable colors give it a personal touch, making it uniquely yours. Whether you’re using it for yourself or giving it as a gift, its functionality and design shine in every byte of charge.

I hope you really enjoyed this little project as much as I did. Thanks for following along, and happy charging!

Thank you :)