How to Balance 12V LiFePO4 Batteries (100Ah, 200Ah, 300Ah) Before Series Connection

When building a 48V battery bank with LiFePO4 batteries, proper balancing before making a series connection is one of the most important steps. Whether you are using 12V 100Ah, 200Ah, or 300Ah LiFePO4 batteries, ensuring balance will maximize system efficiency, prevent overcharging/over-discharging, and extend battery lifespan.

Why Balancing Is Important

LiFePO4 batteries connected in series (4S to create 48V) must start at the same voltage level. If one battery is lower or higher than the others, the imbalance can:

• Cause uneven charging and discharging,

• Put stress on individual battery BMS units,

• Shorten the overall cycle life of the system.

By balancing before series connection, you make sure all batteries “speak the same language” in terms of voltage.

Recommended Balancing Method (for 12V 100Ah, 200Ah, 300Ah)

1. Charge each battery individually with a LiFePO4-compatible charger until fully charged.

2. Let the battery rest for 2 hours to stabilize the open-circuit voltage.

3. Connect all the batteries in parallel for 24 hours. During this time, the batteries will naturally balance with each other, equalizing their voltages.

4. After 24 hours in parallel, reconfigure the batteries into a 4S (48V) series connection.

This simple process ensures that your 12V LiFePO4 batteries are balanced and ready to operate safely in a 48V system.

Technical Tips for a Stable 48V System

• Use cables of equal length and thickness when connecting batteries in parallel or series.

• Make sure all batteries have the same BMS specifications. Mixing different models can cause communication or performance issues.

• For high-capacity batteries like 12V 200Ah or 300Ah, balancing is even more critical due to larger current loads.

• Consider adding a battery monitor (such as a Victron SmartShunt) for real-time tracking of voltage and current.

• If using an inverter or solar charge controller, check that it is compatible with 48V LiFePO4 battery banks.

Final Thoughts

Taking the time to properly balance your 12V 100Ah, 200Ah, or 300Ah LiFePO4 batteries before series connection will give you a more reliable, efficient, and long-lasting 48V energy storage system.

Whether for home solar storage, RV power systems, or off-grid setups, this balancing method is one of the best practices to protect your investment and ensure smooth performance.