DIY Power Bank: How to Build Your Own Portable Charger at Home

Thinking about creating your own DIY power bank to stay powered on the go? Instead of settling for off-the-shelf options, you get to decide exactly how much power you want, what features to include, and how it looks.

In this guide, you’ll learn what components you need, how to put them together step by step, and what to watch out for along the way. Whether you’re doing it to save money, learn something new, or just enjoy the process—this one’s for you.

How to DIY Power Bank Charger

If you’ve worked with basic electronics before—things like soldering or using a multimeter—then building a DIY portable battery charger is fairly easy. If not, it’s a great beginner-to-intermediate project to build confidence. The components are simple, and the wiring isn’t too complex. Let’s get into it!

Essential Components and Tools for a DIY Power Bank

Before we start on how to make a portable phone charger, let’s first go through the core components and tools you’ll need:

Batteries – The Power Source

Most DIY power banks use lithium-ion (Li-ion) or lithium polymer (LiPo) batteries because they pack a lot of energy into a small size. A single cell usually provides 3.7V.

• 18650 Li-ion batteries are the most common—cylindrical, widely available, and easy to work with.
• LiPo batteries are flatter and more flexible in shape, making them ideal if you want a slimmer design.

Always use matching batteries (same model, capacity, and charge level) to balance and prevent overheating. Do not use recycled cells from old laptops unless tested properly. Protected batteries come with built-in safety circuits, known as protection circuit board (PCB). If you use unprotected ones, your charging board must handle safety features like overcharge protection.

Charging Board / Module – The Brain

The charging board manages battery charging and controls the power flow to your devices. It usually includes:

• BMS (Battery Management System): Protects batteries from overcharging, over-discharging, and short circuits. It’s a must if you’re using unprotected batteries.
• Boost Converter: Raises battery voltage from 3.7V to 5V for USB output.
• Input Port: For charging your power bank (Micro USB, USB-C, etc.).
• Output Port(s): Usually USB-A or USB-C, where you connect devices.

TP4056 is a popular module for DIY projects because it includes all necessary safety features.

Casing / Enclosure – The Protection

Your enclosure keeps everything safe and makes the power bank portable.

Options include:

• 3D Printed Cases: Fully customizable but requires access to a printer.
• Repurposed Boxes: Like old chargers or mint tins—cheap and eco-friendly.
• Pre-made Kits: Designed for DIY power banks with slots for batteries and ports.

Key features to think about:

• Space for all components without cramping.
• Openings for USB ports, switches, and indicators.
• Some ventilation for heat management.
• Secure mounting for internal parts to prevent shifting.

Wiring & Connectors – Making the Links

Wires connect the batteries, charging board, and other components.

• Wire Type: Use stranded wire for flexibility, especially in tight spaces.
• Gauge (AWG): 22–24 AWG is usually good for power banks. Lower AWG = thicker wire = more current.
• Connectors (Optional): For switches, LEDs, or modular battery packs. Make sure they match your wire gauge and current needs.

Optional Add-ons

These aren’t essential but can add convenience or cool features:

• Switch: Lets you manually turn the power bank on/off.
• LED Indicators: Show battery status or charging progress.
• Display Module: For real-time data like voltage, current, or charge level.
• Extra USB Ports: For charging multiple devices at once.

Tools You’ll Need

Of course, you’ll need a few basic tools:

• Soldering iron + solder – For connecting wires and components securely.

• Nickel Strips or Solder Tabs – Used for building battery pack connections.

• Wire strippers/cutters – To trim and prep your wires.
• Multimeter – For checking voltages and verifying connections.
• Hot glue gun (optional) – Helps secure parts inside the case.

• Heat shrink tubing or electrical tape – For holding batteries together during the assembly and insulating exposed wires.

• Small screwdrivers – Handy for assembling enclosures.
• Tweezers or pliers – Useful for handling small parts and wires.

Step-by-Step Assembly Guide

Once you’ve gathered your components and tools, follow these steps on how to make a portable charger at home:

Step 1: Test Your Batteries and Match Voltages

Before anything else, the first step on how to make a portable battery charger is to test the voltage of each individual cell. All batteries should be within 0.1V of each other, especially when connecting in parallel, to prevent dangerous current surges between mismatched cells.

Step 2: Choose a Configuration (Typically Parallel)

For most DIY power banks, you’ll be using a parallel configuration. This keeps the overall voltage around 3.7V while increasing the total capacity—great for extending how many times you can charge your devices.

In a parallel setup:

• All positive terminals (+) of the batteries are connected together.
• All negative terminals (–) are connected together.

Step 3: Join the Batteries: Spot Welding Preferred

To physically connect the cells, the safest and most effective method is spot welding using pure nickel strips. It creates solid, low-resistance connections without applying heat directly to the battery terminals:

1. Lay out your battery configuration first.
2. Spot weld nickel strips across all positive terminals, then across all negative terminals, depending on your layout.
3. You can then add two main output wires: one from the positive terminal strip, and one from the negative strip. These will connect to your charging board later.

If spot welding isn’t an option, careful soldering can work, but it requires extra caution. Before soldering, you can first use electrical tape to hold the batteries together. Excessive heat can damage lithium-ion cells, so keep soldering time to a minimum, and only solder to the ends (terminals) of the cells—never the sides.

Step 4: Insulate and Secure the Pack

Once your battery pack is assembled and your output wires are attached, use heat shrink tubing or electrical tape to cover any exposed terminals, nickel strips, or solder joints. Wrap the battery pack to prevent shifting or short circuits inside the case later.

Step 5: Connect the Battery Pack to the Charging Board

With the battery pack ready, the next step is to wire it to your charging board. Most boards, such as the popular TP4056 module, are labeled with terminals like B+ and B− (sometimes BAT+ and BAT−). These are where your battery connects.

Carefully solder the positive wire from your battery pack to the B+ terminal, and the negative wire to the B− terminal. Double-check your connections before powering anything on. Reversed polarity can permanently damage the charging board and the batteries.

If you’re unsure, confirm the battery pack’s polarity with your multimeter first. Once you’re confident in your connections, cover the solder joints with heat shrink tubing or a bit of electrical tape to prevent accidental shorts or wear.

Step 6: Integrate Optional Components

• Add a Power Switch: If you’re including a manual on/off switch, cut the positive wire between the battery and the charging board, and solder each cut end to the switch terminals. This gives you control over when the power bank is active. Be sure to insulate the switch connections.
• Wiring LEDs for Status Indication: Some charging boards support external status LEDs. If yours does, follow the board’s labels and polarity guides. If not, you can still wire an LED with a current-limiting resistor, usually 220–470 ohms depending on your supply voltage and LED specs.
• Connecting a Display: If you’re adding a voltage or battery level display, connect it to your board (or a microcontroller) using I²C or SPI communication lines. Follow the display’s datasheet for proper pin mapping and power requirements. This is more advanced but adds a nice touch of usability.

Step 7: Test the Circuit

Once all your connections are complete, you’re ready for the most satisfying step on how to make portable mobile charger: testing.

• Initial Charging Test: Plug in a USB wall charger to your power bank’s input port (Micro USB or USB-C). The board’s indicator LED should light up to show that charging has begun. Let it charge for a while to build up energy in the battery pack.
• Device Charging Test: After charging, unplug the wall adapter and connect a device to one of the USB output ports. Your phone or USB gadget should begin charging. Watch for any output indicator lights, if your board has them.
• Verify Output Voltage and Capacity: Use your multimeter to check the USB output voltage while charging a device—it should read close to 5V. For a more in-depth check, you can use a USB power meter to monitor current and even test the full capacity of your power bank.

Step 8: Secure and Enclose Everything

Confirmed everything is working? It’s time to fit everything into your case. Lay out the components inside your enclosure so that wires aren’t under tension and everything fits neatly. USB ports, switches, and LEDs should line up with any cutouts in your case—or you’ll need to make some adjustments.

To prevent the components from shifting around during use, secure them with hot glue, double-sided foam tape, or even zip ties if your case allows for it. If you’re using a 3D-printed case, it might already have compartments or mounting points designed to hold each component in place. In repurposed enclosures, you’ll need to improvise a little—foam padding or Velcro strips can help.

Be especially careful not to pinch or bend wires while closing the case. Route everything cleanly and double-check that nothing is shorting or exposed before sealing it up with screws or clips.

Now give it a final check and you’re ready to use your custom DIY power bank!

Safety Tips During Assembly

Working with batteries requires care. A wrong connection or short circuit can lead to overheating or damage, so it’s important to take safety seriously when learning how to make a portable cell phone charger. Here are a few key tips to keep in mind:

• Use Quality Batteries: Stick to genuine, name-brand 18650 cells from reliable sources. Avoid damaged or recycled batteries unless you've tested them thoroughly.
• Check Polarity: Always double-check positive and negative terminals before connecting anything. Reversed polarity is a common cause of circuit failure and overheating.
• Prevent Short Circuits: Insulate exposed wires and solder joints with heat shrink tubing or electrical tape. Trim excess leads to avoid accidental contact.
• Use Protection Circuits: Make sure your charging module includes overcharge, discharge, and short-circuit protection (like a TP4056 with built-in safety features).
• Work in a Well-Ventilated Space: If you’re soldering, make sure you’re in a well-ventilated area. Solder fumes can be irritating or harmful over time.
• Minimize Heat Exposure: When soldering, only apply the soldering iron to battery terminals briefly to prevent overheating and potential damage.

Advantages and Limitations of DIY Power Banks

Building your own DIY power bank comes with some great benefits—but there are also a few trade-offs to consider. Here’s a breakdown to help you decide if going the DIY route is right for you.

Advantages

• Customization: You get full control over the size, battery capacity, number of USB ports, and even add-ons like LED indicators or solar charging. You build exactly what you need.
• Cost-Effective: If you already have parts like recycled batteries or a case, a DIY power bank can be cheaper than buying a new one—especially for higher-capacity builds.
• Learning Experience: You gain hands-on knowledge of electronics, batteries, charging circuits, and power conversion. It’s a great way to build skills and confidence.
• Repairable: If anything goes wrong, you can open it up and fix it yourself.

Limitations

• No Fast Charging (Usually): Most simple DIY builds don’t support fast charging standards like QC or PD. That means slower charging for some devices.
• Bulkier Designs: DIY power banks are often larger than commercial ones with the same capacity, especially if you’re using standard batteries and modules. They also lack the aesthetic appeal.
• Safety Risks: Without proper assembly and protection circuits, there’s a real risk of overheating, short circuits, or battery failure.
• Not Always Cheaper: If you need to buy all the components from scratch, the cost can quickly add up—sometimes more than a reliable off-the-shelf power bank.

As you can see, DIY models are great for learning and basic use—but once you start adding extras, they often become less practical, less reliable, and not as cost-effective. If you’re not confident in your skills or looking for fast charging, smart features, portability, and top-notch safety, a well-designed off-the-shelf power bank is still your best bet.

Take the Anker Prime Power Bank (9.6K, 65W, Fusion) for example. It’s compact, doubles as a wall charger, features two USB-C ports with 65W PD 3.0 fast charging, and has a capacity of 9,600mAh—enough to charge an iPhone 15 twice or even power a small laptop.

It also comes with a braided USB-C to USB-C cable, a smart 1.3-inch LCD display to show real-time charging stats, and Anker’s ActiveShield 3.0 technology, which runs millions of safety checks daily to keep your devices protected.

DIY has its charm, but for a compact, travel-ready solution with cutting-edge tech and built-in safety, a device like this will always be a smart choice.

Conclusion

Putting together a DIY power bank isn’t just about saving a few bucks—it’s about understanding how these everyday tools actually work. By the time you’re done, you’ll have something that’s not only useful but also customized to your needs. Sure, it might take a little trial and error, but that’s part of the fun. Just remember to follow the safety tips, double-check your connections, and enjoy the satisfaction that comes with building something yourself!

FAQ

How can I make a homemade power bank?

To make a homemade power bank, you’ll need rechargeable batteries (like 18650 cells), a charging module (such as a TP4056) with a built-in boost converter and BMS, USB output ports, and a case to hold everything. Connect the batteries to the charging board, wire the output ports, and secure all components in an enclosure. Make sure to test everything before closing the case and always follow safety precautions when working with batteries.

Is it cheaper to build your own battery bank?

It can be—especially if you already have some of the tools or spare parts like 18650 batteries from old devices or can source quality batteries at a low cost. DIY power banks often cost less than high-end commercial ones with the same capacity. However, if you need to buy everything (batteries, charging module, case, and soldering supplies) from scratch, the savings might be small.

What is the difference between a power bank and a power pack?

The terms “power bank” and “power pack” are often used interchangeably, but they can mean slightly different things depending on context. A power bank usually refers to a small, portable battery used to charge phones, tablets, or other USB devices. A power pack, on the other hand, can refer to a broader range of battery systems, including larger ones used for tools, laptops, or even backup power setups for home appliances.

Is it safe to carry a DIY power bank on an airplane?

Carrying a DIY power bank on an airplane is generally not recommended due to safety concerns. While general regulations from the TSA and FAA allow lithium-ion batteries under 100Wh in carry-on luggage, homemade devices lack standardized testing and safety features present in commercially manufactured power banks, increasing the risk of overheating or fire. Additionally, their non-standard appearance may cause issues during airport security screening.