4S 1.2A Lithium Battery Active Inductive Equalizer Balancer Module

4S 1.2A Lithium Battery Active Inductive Equalizer Balancer Module is a high-efficiency adjacent-cell inductive energy-transfer active balancer designed for 4-series (4S) Li-ion (14.8V/16.8V) and LiFePO4 (12.8V/14.6V) battery packs. Unlike passive resistive balancers that waste excess energy as heat at only 30–66mA during the final 4.2V charging stage, this active equalizer uses shielded power inductors and synchronous MOSFETs to shuttle up to 1.2A of current from higher-voltage cells directly into adjacent lower-voltage cells whenever a voltage difference exceeds 0.1V.

Key Features:

• High-Current 1.2A Active Energy Transfer: Transfers up to 1.2A between adjacent cells (>90% efficiency)—nearly 20× faster than 66mA passive bleed resistors, without generating heat.
• Works for Both Li-ion (3.7V) & LiFePO4 (3.2V) 4S Packs: Operates across a wide 2.0V to 4.5V per-cell range, making it universally compatible with 4S ternary Li-ion, LiPo, and LiFePO4 chemistries.
• Automatic Voltage-Delta Triggering: Initiates active balancing automatically whenever adjacent cells drift apart by ≥ 0.10V (during charging, discharging, or rest) and stops once cells equalize within ≤ 0.03V.
• Ultra-Low Sleep Quiescent Current: Automatically enters microamp sleep mode if cell voltage drops below 3.0V to prevent draining idle packs.
• Includes Plug-and-Play 5-Pin JST-XH Balance Harness: Supplied with a color-coded 5-wire balance cable for easy connection to your 4S pack.

Technical Specifications:

• Supported Pack Configuration: 4S (4 Series Cells)
• Compatible Battery Chemistries: Ternary Li-ion / 18650 / 21700 (3.7V Nominal), LiPo, and LiFePO4 (3.2V Nominal)
• Single-Cell Working Voltage Range: 2.0V to 4.5V DC
• Maximum Balance Current: Up to 1.2A (Proportional to Voltage Delta ΔV; ~0.5A–1.2A)
• Balance Trigger Threshold: Adjacent Cell Voltage Difference ΔV ≥ 0.10V
• Balance Stop Accuracy: Within 0.03V (30 mV)
• Energy Transfer Topology: Adjacent-Cell Synchronous Inductive Buck-Boost Shuttle
• Operating Temperature Range: -20°C to +60°C

Mechanical Specifications:

• PCB Material: FR-4 Double-Sided Black/Blue PCB with 3 × Shielded Power Inductors
• Interface: 5-Pin JST-XH 2.54mm Balance Header (`B-`, `B1`, `B2`, `B3`, `B4`)

Dimensions:

• Length: ~60 mm
• Width: ~25 mm
• Height: ~8 mm
• Weight: ~14 g

Pinout and Wiring:

• B- (Black Wire): Connect to Cell 1 Negative (Pack Negative 0V).
• B1: Connect to Cell 1 Positive / Cell 2 Negative junction.
• B2: Connect to Cell 2 Positive / Cell 3 Negative junction.
• B3: Connect to Cell 3 Positive / Cell 4 Negative junction.
• B4 / B+ (Red Wire): Connect to Cell 4 Positive (Pack Positive 12.8V/14.8V).
• Wiring Precaution: Solder all 5 wires to the battery cells BEFORE plugging the white JST-XH connector into the equalizer board to prevent accidental pin-shorting!

Datasheet Reference:

• Circuit Architecture: ETA3000 / Synchronous Inductive Active Cell Equalizer IC + Shielded SMD Power Inductors

Commonly Used in:

• 12.8V 4S LiFePO4 Solar & Inverter Battery Banks (32650 / Prismatic 100Ah+)
• 14.8V / 16.8V 4S 18650 Power Tool & E-Mobility Packs
• Rejuvenating Aged or Slightly Mismatched 4S Lithium Packs
• High-Drain Marine, RV, and Off-Grid Energy Storage

Applications:

• Pairs alongside any 4S BMS (`4S 30A`, `4S 40A`, or `4S 100A LiFePO4`) to provide true 1.2A active cell balancing across large capacity battery banks.
• Eliminates premature BMS high-voltage or low-voltage cut-offs caused by a single weak or out-of-balance cell group.
• Equalizes top-charged 4S LiFePO4 packs where flat voltage curves make passive balancing ineffective.

Equivalent Models:

• 4S 14.8V Li-ion Balancer Board: Economical 66mA passive resistive 4S balancer board for 4.2V Li-ion cells.
• 3S 11.1V 18650 Lithium Battery Polymer Battery Equalizer Board: 3-cell (3S) 1.2A inductive active equalizer module.

Package Includes:

• 1 × 4S 1.2A Lithium Battery Active Inductive Equalizer Balancer Module