How to Build a 12V 100Ah LiFePO4 Battery Pack at Home.

Building your own 12V 100Ah LiFePO4 (Lithium Iron Phosphate) battery pack may sound like a complex task, but with the right knowledge, tools, and precautions, it’s much easier than you might think.

Whether you're planning for solar energy storage, backup power for your home, or DIY projects, assembling your own battery pack can be a smart and rewarding experience.

In this guide, I’ll explain everything you need to know to successfully create a high-quality, reliable 12V 100Ah battery pack — from scratch.

Why Choose a 12V 100Ah LiFePO4 Battery Pack?

LiFePO4 batteries are gaining massive popularity over traditional lead-acid batteries, and for good reason:

• Faster charging time compared to lead-acid batteries.
• Lighter weight, making them easier to handle.
• Longer backup duration, ideal for inverters and solar systems.
• Outstanding life span, lasting 8 years or more.
• Almost zero maintenance requirements.

Plus, understanding how to build a 12V pack will make it easier to scale up to bigger systems like 24V, 48V, or even 60V in the future.

Understanding the Basics

Before starting, you must define your requirement clearly.
For this project, the goal is a 12V 100Ah battery pack.

To achieve this, we will use four 3.2V 100Ah Prismatic Cells, connected in series.
Series connection multiplies the voltage while keeping the ampere-hour capacity the same, perfect for reaching the desired 12.8V output.

If you’re wondering why not connect them in parallel — remember, parallel connections are used to increase capacity (Ah), not voltage.

What You Will Need

To successfully build the battery pack, gather these essential materials:

• Four 3.2V 100Ah Prismatic Cells (Hi-Star recommended)
• Smart BMS (DALY Smart BMS 4S)
• Busbars and screws for secure connections
• Battery spacers or epoxy sheets to maintain safe cell distance
• Filament tape for tight packing
• Multimeter to check voltages and continuity
• Voltage display meter (optional but useful)
• Protective cabinet or epoxy casing for enclosure

Before assembly, check the Internal Resistance (IR) of each cell.
Healthy cells generally show an IR around 0.25 mΩ or lower, ensuring high efficiency and longer life.

Preparing the Cells

Balancing the cells is one of the most important steps before starting assembly.

To actively balance:

• Connect all positive terminals together.
• Connect all negative terminals together.
• Leave them connected overnight.

This helps equalize the voltage across all cells, preventing imbalance problems later.
Skipping this step can cause long-term damage or reduced performance.

Assembly and Connection

Begin by neatly arranging the cells side-by-side.
Use filament tape to wrap them tightly so they don’t move.

Next, connect the busbars:

• Negative of the first cell connects to positive of the second cell.
• Continue this pattern for all four cells.

Always tighten the bolts securely — loose connections can cause heat buildup and major safety issues.

Installing the BMS

After the cells are properly connected, it’s time to install the Smart BMS:

• B- terminal of the BMS connects to the main battery negative.
• P- terminal is the output negative.
• B+ remains the output positive directly from the battery.

Carefully connect the balancing wires in sequence:

• B0 connects to cell 0V
• B1 connects to cell 1
• B2 to cell 2
• B3 to cell 3
• B4 to final positive

Important: Disconnect the BMS balancing plug during wiring. Reconnect it only after verifying correct voltages with a multimeter to avoid short circuits.

Once wiring is complete, secure the BMS properly on top of the pack using double-sided tape or filament tape.

Why I Chose DALY Smart BMS for This Build

When it comes to building reliable and long-lasting LiFePO4 battery packs, choosing the right BMS (Battery Management System) is absolutely critical.
After testing various options over the years, I found DALY Smart BMS to be one of the most trusted, efficient, and feature-rich solutions available today.

For this 12V 100Ah pack, I used the DALY 4S Smart BMS — and here’s why it stands out:

• Superior Protection:
• DALY BMS provides full protection against overcharge, over-discharge, overcurrent, short circuits, and temperature extremes.
• Smart Monitoring:
• Using the DALY Smart BMS app (available on the Play Store), I can monitor real-time voltage, current, battery temperature, and even balance the cells actively.
• Active Balancing Feature:
• One of the premium features is active balancing, which ensures that all cells maintain a healthy voltage range, improving the lifespan of the entire pack.
• Strong Build Quality:
• The BMS is built with high-grade components, making it highly durable even in tough working conditions.
• Easy Installation:
• The DALY Smart BMS wiring is straightforward, well-documented, and beginner-friendly, making it perfect for DIY enthusiasts and professionals alike.

Whether you're building a battery pack for an inverter, solar storage, or even an electric vehicle project, DALY BMS ensures your setup remains safe, stable, and efficient.

Special thanks to DALY for supporting this project and providing high-quality BMS solutions that empower DIY creators like us.

Enclosure and Final Touches

After ensuring all connections are solid and tested:

• Wrap the entire battery pack tightly again with filament tape.
• Insert it into a durable battery cabinet or protective casing.
• Attach the voltage display if using.

If you don’t have a cabinet, you can build a custom case using epoxy sheets or reinforced cardboard.

Testing the Battery Pack

Now, it’s time to test your homemade 12V 100Ah battery pack in action.

We connected our pack to a Luminous Smart Inverter, running a 200W LED load.
The system provided over 8 hours of backup time — proof that the battery was performing optimally.

By using the Smart BMS App (available on the Play Store), you can monitor:

For more, you can watch our YouTube video.

• Cell voltages
• Battery temperature
• Charge and discharge cycles
• Overall battery health

The application even shows active balancing in real time, ensuring that the cells maintain proper voltage alignment during use.

Final Thoughts

Creating a 12V 100Ah LiFePO4 battery pack at home not only saves costs but also gives you complete control over the quality of your energy storage system.
Whether for an inverter, solar setup, or any DIY project, a well-built lithium battery pack can be a game-changer.

If you want ready-made battery packs or high-quality Prismatic cells, you can always reach out to us through our WhatsApp Store for premium products at competitive pricing.

Thank you for reading!
If you have any questions, feel free to comment below. 🚀