​​LiFePO4 Battery Series and Parallel Connection Guide​​

LiFePO4 batteries can be connected in series (to increase voltage) or parallel (to increase capacity). Below is a detailed breakdown of configurations, best practices, and critical considerations based on technical guidelines and industry standards:

1. Series Connection

Purpose: Increase total voltage while maintaining capacity.
Example:

• 4 x 3.2V LiFePO4 cells in series → 12.8V system (nominal voltage).

Steps:

1. Battery Selection: Use cells with identical voltage, capacity, and chemistry (e.g., all 3.2V 100Ah cells).
2. Physical Wiring:
   • Connect the positive terminal of Cell 1 to the negative terminal of Cell 2.
   • Repeat for subsequent cells (Cell 2–3, Cell 3–4).
3. Voltage Balancing:
   • Pre-charge each cell to full charge.
   • Use a BMS to monitor and balance cells during operation.

Key Considerations:

• Charging Voltage: Must match the series total (e.g., 12.8V system requires a 14.4–14.6V charger) 
• Current Limitation: Ensure the charger/current source matches the battery’s max discharge rate (e.g., 100A for a 100Ah cell).

2. Parallel Connection

Purpose: Increase total capacity while maintaining voltage.
Example:

• 2 x 100Ah LiFePO4 cells in parallel → 100V system, 200Ah capacity.

Steps:

1. Battery Selection: Cells must have identical voltage, capacity, and state of charge (SOC).
2. Physical Wiring:
   • Connect all positive terminals together.
   • Connect all negative terminals together.
3. Balancing:
   • Fully charge each cell before connecting.
   • Use a BMS to ensure uniform discharge/charge distribution.

Key Considerations:

• Discharge Rate: Parallel configurations share current; ensure individual cells can handle the load (e.g., 200A total load requires ≥100A per cell).
• Thermal Management: High discharge rates may cause localized heating; monitor cell temps

3. Series-Parallel Hybrid Configurations

Purpose: Combine voltage and capacity scaling
Steps:

1. Build parallel modules
2. Connect modules in series

Advantages:

• Optimizes energy density (Wh) and power (W).
• Reduces stress on individual cells 

4. Common Mistakes & Solutions

Summary Table