Freen-BSL-R Energy Storage

The Freen-BSL-R is a low-voltage, rack-mount sodium-ion battery module designed for commercial, industrial, and telecom energy storage. Built around advanced Na-ion layered oxide chemistry, it delivers the same safety, thermal stability, and long cycle life as the residential BSL line, in a compact 19″ rack-compatible form factor.

Engineered as a 48 V, 3U rack module, Freen-BSL-R integrates seamlessly with hybrid and off-grid inverters, telecom rectifiers, and UPS systems, making it the building block for server rooms, telecom base stations, C&I peak shaving, and multi-rack storage architectures. Up to 16 modules in parallel for systems up to 51.2 kWh on a single DC bus.

Key Benefits

19″ Rack-Native Design

Standard 3U, 19″ format (483 × 575 × 133 mm). Drops into any server rack, telecom cabinet, or wall-mount enclosure without custom brackets or adapters.

Safe Sodium-Ion Technology

No thermal runaway under any abuse condition. No special ventilation, no fire suppression, no restricted installation zones. Deploy in server rooms, telecom shelters, and equipment closets where lithium batteries trigger fire code complications.

High Energy Efficiency

Round-trip efficiency above 97%, ensuring minimal losses during charging and discharging.

10,000 Full Cycles

Energy retention ≥60% at end of life. At one cycle per day, over 27 years of operation. Designed for daily duty cycles: peak shaving, tariff arbitrage, telecom backup.

Wide Temperature Tolerance

Discharge from -30°C to +60°C without external heating. Charge from 0°C to +55°C. Ideal for outdoor telecom cabinets, unheated equipment rooms, and harsh industrial environments.

Lightweight and Compact

50.25 kg per module, the lightest unit in the Freen lineup. One person can handle installation into a rack. No forklift, no crane.

Modular & Scalable

Each unit provides 3.2 kWh. Up to 16 modules in parallel for a maximum of 51.2 kWh per group, maintaining a safe 48 V architecture. Multiple groups can be combined for larger systems (100+ kWh with appropriate DC distribution).

Drop-In Lead-Acid Replacement

48 V nominal, rack-mount form factor, CAN/RS485 communication. Replaces legacy VRLA battery strings in telecom BBU applications with 5x the cycle life, 3x the energy density, and zero maintenance.

Technical Highlights

• Nominal Voltage: 48 V
• Voltage Range: 40–60 V
• Usable Energy (per unit): 3.2 kWh
• Capacity: 66 Ah
• Max Continuous Power: 2.1 kW
• Max Current: 43.75 A
• Cycle Life: >10,000 cycles to 60% SOH
• Efficiency: >97%
• Cooling: Natural convection (no fans)
• Installation: Indoor, 19″ rack-mount (3U)
• Dimensions: 483 × 575 × 133 mm
• Communication: CAN & RS485 for inverter/rectifier integration
• Ingress Protection: IP20
• Weight: 50.25 kg
• Certifications: CE, UN38.3, IEC 62619

Smart Battery Management

An advanced integrated BMS continuously monitors cell voltage, current, and temperature. It provides:

• Over-charge / over-discharge protection
• Short-circuit and over-current protection
• Active cell balancing
• Automatic shutdown under unsafe conditions
• Master-Slave RS485 daisy-chain between modules
• CAN communication with Victron, Deye, GoodWe, and 50+ compatible inverters
• Remote monitoring included at no extra cost

Ideal For

✔ Telecom base station backup (drop-in VRLA replacement)

✔ Server room and data centre UPS

✔ C&I peak shaving and tariff arbitrage

✔ Multi-rack storage systems (100+ kWh)

✔ OEM integration into third-party ESS platforms

✔ Cold-climate outdoor cabinets and shelters

✔ Pilot and test installations

Warranty

Backed by a 10-year warranty with guaranteed energy throughput (MWh) over the warranty period. If the battery underperforms versus the warranted throughput, we replace it.