Step-by-Step Guide: Building a DIY 12V 18650 Battery Pack


Are you tired of constantly replacing batteries in your devices? Do you want to save money and be more eco-friendly? Building a DIY 12V 18650 battery pack could be the solution for you! With just a few materials and some basic soldering skills, you can create your own rechargeable battery pack that will power all sorts of electronics. In this step-by-step guide, we’ll show you how to make your own battery pack from scratch. Whether it’s for powering up an old robot or creating a portable solar charging station, building your own battery pack is not only fun but also practical. So grab your tools and let’s get started!

What You’ll Need

Before you dive into building your DIY 12V 18650 battery pack, it’s important to gather all the necessary tools and materials. Here is a list of what you’ll need:

Firstly, you will need a set of 18650 batteries. You can purchase these online or from your local electronics store. Make sure to get high-quality batteries that are rated for at least 3-4 amps.

Next up, you’ll need some nickel strips or wire which will be used to connect the batteries in both series and parallel configurations. The thickness of the strip should be around 0.15mm – anything thinner than this may not conduct enough current.

You’ll also require a soldering iron along with some flux and soldering wire. Remember to use caution while handling hot irons as mishandling could lead to burns or other injuries.

In addition, it’s worth investing in a multimeter so that you can test the voltage of your battery pack once it has been assembled.

Don’t forget about safety gear such as gloves and eye protection when working with batteries!

By ensuring that you have all these items on-hand before starting your project, you’ll make the process much smoother and safer overall!

Step 1: Connect the 18650 Batteries in Series

Step 1: Connect the 18650 Batteries in Series

Connecting the 18650 batteries in series is the first step towards building your DIY battery pack. This process involves linking each cell’s positive terminal to the next cell’s negative terminal, forming a chain of cells with an overall voltage equal to the sum of all individual voltages.

To begin, gather your 18650 batteries and ensure that they have matching voltages. Next, identify which end of each battery is positive and which is negative. You can do this by checking the markings on each battery or observing their physical shape.

Once you have identified these details, take a wire and attach it to one end of your first battery’s positive terminal. Then connect this wire to another wire attached to your second battery’s negative terminal. Continue linking wires between adjacent batteries until you reach the last one.

Make sure that there are no exposed wires or loose connections before moving onto Step 2: connecting the batteries in parallel. By following these steps carefully, you’ll be well on your way towards creating a reliable and efficient homemade energy source for all kinds of projects!

Step 2: Connect the 18650 Batteries in Parallel

Now that you have connected the 18650 batteries in series, it’s time to connect them in parallel. This will increase your battery capacity while keeping the voltage constant.

To connect them in parallel, take two sets of wires and attach one end of each set to the positive and negative terminals of one battery respectively. Do this for all batteries.

Once you have connected all the batteries with wires, use a multimeter to check if they are balanced. If there is any difference in their voltage levels, charge or discharge accordingly until they are at equal levels.

After ensuring balance among all cells, join both sets of wires together using a soldering iron. This will create two larger wire connections – one for positive terminal and another for negative terminal.

Double-check your connections before proceeding onto step 3. A mistake here could lead to short-circuiting or damaging your device later on.

Step 3: Solder the Wires to the Batteries

Step 3: Solder the Wires to the Batteries

Once you have connected your batteries in series and parallel, it’s time to solder the wires onto each battery. This step requires precision and patience since overheating or damaging a battery can be dangerous.

Firstly, make sure that you have the right tools for this job. You will need a soldering iron, flux paste (to facilitate the flow of solder), and thin gauge wire. It’s important to use thin gauge wire so that it can fit comfortably on each battery terminal without adding extra weight or bulk.

Before beginning any soldering work, ensure that your workspace is clean and free from clutter. The last thing you want is for an accidental knock of your elbow to send hot molten metal flying everywhere!

When ready, carefully apply flux paste onto one terminal of each battery before placing a small amount of solder on top of it. Then attach one end of your thin gauge wire onto this same point while still holding everything steady with tweezers or pliers.

Repeat these steps for all terminals until every battery has two wires attached – one positive (red) and one negative (black). Use heat shrink tubing over each connection point before moving on to Step 4.

Soldering may take some practice if you are new at it but be patient with yourself! Once done correctly, this step ensures that electricity flows smoothly through all batteries in unison without any interruptions or risk of damage due to poor connections.

Step 4: Attach the Battery Pack to Your Device

After successfully building your 12V 18650 battery pack, the next step is to attach it to your device. This can vary depending on what you’re powering with your new battery pack, but there are some general steps you can follow.

Firstly, make sure that your device’s power input matches the voltage of your battery pack. If they don’t match, you may need to use a voltage regulator or step-up/down converter.

Next, determine how you will connect the battery pack to your device. Depending on the size and shape of both components, this could involve using wires with alligator clips or soldering wires directly onto terminals.

When connecting the wires from your battery pack to your device, ensure that they are properly secured and insulated. You don’t want any loose connections that could cause electrical shorts or other issues.

Once everything is connected properly and securely, turn on your device and test it out! If it doesn’t work as expected or if there are any issues with overheating or other problems, double-check all of your connections before trying again.

Attaching a DIY 12V 18650 battery pack to a device requires careful attention and adherence to safety guidelines. But with proper planning and execution, it can be a rewarding way to power electronics projects without relying solely on traditional batteries or AC outlets.


Building your own DIY 12V 18650 battery pack can be a fun and rewarding project for anyone interested in electronics. By following this step-by-step guide, you should have no trouble assembling a high-quality battery pack that will power your devices for years to come.

Remember to take all necessary safety precautions when working with batteries, including wearing protective gear and avoiding short circuits. With patience and attention to detail, you can create a safe and reliable battery pack that meets your needs.

By building your own battery packs, you can save money while enjoying the satisfaction of creating something with your hands. So why not give it a try? We hope this guide has been helpful in getting you started on your DIY journey!