Remember one core rule:

Match the cell type and series quantity first → Calculate current accurately → Ensure 4 basic protection functions → Choose balance & temperature functions by application scenario → Finally check communication protocol and workmanship

1. Confirm Basic Battery Information (Must calculate first)

1) Cell Type (The most critical factor)

• NCM Ternary Lithium: Nominal voltage 3.7V per cell; Overcharge: 4.20–4.25V; Over-discharge: 2.5–2.8V
• LFP Lithium Iron Phosphate: Nominal voltage 3.2V per cell; Overcharge: 3.65–3.70V; Over-discharge: 2.5–2.8V
• Must use a dedicated BMS for the corresponding battery chemistry. Do not mix use.

2) Series Quantity (S) (Determines total voltage & BMS model)

• 12V ≈ 4S (LFP) / 3S (NCM)
• 24V ≈ 8S / 7S
• 48V ≈ 16S / 13S
• 60V ≈ 20S / 16S
• The BMS must fully match the cell series number (e.g., 16S battery only uses a 16S BMS)

3) Capacity (Ah)

2. How to Choose Current Rating

1) Continuous Discharge Current (Core parameter)

• Electric vehicles: ≥ Controller current limit × 1.2
   

  (Example: 20A current limit → choose 25A or above)

• Energy storage / Inverter: ≥ Inverter power ÷ Minimum battery voltage × 1.2
• Formula: I=P÷Vmin​×1.2

2) Peak Current

3) Common Port vs Split Port

• Common Port (2 wires): Charge & discharge share one port, simple wiring, cost-effective; suitable for low current (≤30A)
• Split Port (3 wires): Separate charge and discharge circuits, better heat dissipation, longer service life; suitable for medium & high power (≥40A)

3. Protection Functions: 4 Basic Protections Are Mandatory

1. Overcharge Protection: Automatically cut off charging when single cell voltage reaches the threshold
2. Over-discharge Protection: Automatically stop discharging when voltage drops below the limit
3. Over-current Protection: Fast cut-off within ≤200ms once current exceeds the set value
4. Short Circuit Protection: Instant cut-off (microsecond level) to prevent fire

Additional Essential Functions (Power Battery & Energy Storage)

• Temperature Protection: Charging range 0–45℃, Discharging range -20–60℃; system shuts down when overheating
• Cell Balancing (Crucial for battery lifespan)
  • Passive Balancing: Low current (30–100mA), low cost; for small capacity batteries (≤20Ah) with small voltage difference
  • Active Balancing: High current (≥1A), high efficiency; for large capacity batteries (≥50Ah), large voltage difference & long lifespan requirements; controls voltage difference within 10–20mV and extends battery life by over 20%
   

4. Model Selection by Application Scenario

1) Low Current (≤30A): Power Tools / Light E-scooters / 12V Energy Storage

• Type: Common port, hardware BMS, passive balancing
• Series: 4S / 8S / 13S / 16S
• Current: 20A / 30A
•  

2) Medium Current (40–100A): E-motorbikes / Tricycles / 48V Energy Storage

• Type: Split port, hardware & software combined, active balancing (for ≥50Ah)
• Series: 13S / 16S / 20S
• Current: 60A / 80A / 100A
•  

3) High Current (≥150A): Electric Vehicles / High-power Energy Storage

• Type: Split port, smart BMS, ≥1A active balancing, CAN communication
• Series: 16S–24S
• Current: 150A / 200A / 300A
•  

5. Common Mistakes & Avoidance Tips for Beginners

1. ❌ Wrong series BMS (e.g., 16S battery with 13S BMS) → Permanent battery damage
2. ❌ Underrated current → Frequent protection triggering, overheating, burnt board
3. ❌ Mix NCM & LFP BMS → Abnormal overcharge/over-discharge, battery bulging & fire hazard
4. ❌ Only focus on low price ignoring workmanship → Falsified specs & failed protection

6. Quick Selection Template (Direct Application)

• Cell type: LFP → Choose dedicated LFP BMS
• Series quantity: 24S → Adopt 24S BMS
• Current: 55A×1.2=66A → Select 80-100A split port BMS
• Balancing: 80Ah → 0.8A-2A Active Balance is sufficient
• Temperature: Mandatory charge & discharge temperature protection
• Communication: Optional Bluetooth APP (monitor voltage / current / temperature)