BEI Maximus UL 20A Battery | 95S4P 366.7V 84.4Ah High-Energy Battery Pack

The BEI Maximus UL 20A 95S4P Battery Pack is an ultra-high-energy, high-voltage battery system designed for advanced aerospace platforms, electric aircraft, UAVs, robotics, and other weight-critical applications requiring substantial energy storage with high specific energy.

Built using 380 BEI Maximus UL 20A lithium-metal cells, the 95S4P architecture provides a 366.7 V nominal system voltage, up to 84.4 Ah typical capacity, and approximately 30.95 kWh of typical stored energy.

Cell Datasheet

BEI’s Maximus UL 20A cell provides a 519 Wh/kg cell-level gravimetric energy density, alongside high discharge capability and operation at temperatures down to −35°C.

BEI Maximus UL 20A Datasheet.pdf

Technical Specifications

Configuration: 95S4P
Cell Count: 380
Nominal Voltage: 366.7 V
Maximum Charge Voltage: 408.5 V
Discharge Cutoff Voltage: 285.0 V

Capacity

Typical: 84.4 Ah @ 0.1C
Minimum: 80.0 Ah @ 0.1C
Rated: 78.4 Ah @ 1C

Energy

Typical: 30.95 kWh @ 0.1C
Minimum: 29.34 kWh @ 0.1C
Rated: 28.58 kWh @ 1C

Charge Current

Standard: 16 A (0.2C)
Maximum: 80 A (1C)

Discharge Current

Standard: 80 A (1C)
Maximum Continuous: 400 A (5C)
Maximum Continuous @ −20°C: 640 A (8C)
Maximum Discharge ≤300 sec: 800 A (10C)
Maximum Pulse ≤10 sec: TBD by BEI

Final pack-level current capability is dependent on busbar design, interconnects, thermal management, BMS architecture, contactors, cabling, connectors, and overall system design.

Internal Resistance

Cell ACIR: ≤1.6 mΩ @ 1 kHz, 30% SOC
Cell DCIR: ≤4.0 mΩ @ 30% SOC

Pack-level resistance is dependent on the complete electrical architecture and interconnection system.

Environmental Specifications

Charge Temperature: +10°C to +45°C
Discharge Temperature: −35°C to +71°C
Storage Temperature: 0°C to +45°C
Maximum Cell Body Temperature: 90°C

Mechanical Specifications

Cell Weight: 157 g each
Cell-Level Mass (380 cells): ~59.66 kg
Finished Pack Weight: Dependent on mechanical structure, BMS, busbars, contactors, wiring, thermal management, and enclosure requirements.

Cell Performance

Cell-Level Gravimetric Energy Density: 519 Wh/kg @ 0.1C
Cell-Level Volumetric Energy Density: 1,282 Wh/L @ 0.1C

Cycle Life:
70 cycles — 0.2C charge / 1C discharge, 100% DOD to 80% SOH
30 cycles — 1C charge / 2C discharge, 100% DOD to 80% SOH

Cell Certification: UN 38.3

BEI Maximus UL 20A Datasheet.pdf

Availability

Lead Time: Approximately 3 weeks

BEI Maximus UL 20A cells are currently intended for testing and evaluation applications, with availability subject to supply. High-voltage systems can be engineered with custom mechanical architecture, BMS integration, contactors, service disconnects, communication interfaces, thermal management, and application-specific electrical integration.

For full technical documentation, integration support, or custom high-voltage battery configurations, please contact our team.