Chinese energy storage system manufacturer Biwatt has introduced a 58 V modular sodium-ion residential storage system for residential applications.

The Nest R5 Series is based on sodium iron pyrophosphate (NFPP) chemistry and spans two configurations: the all-in-one PowerNest R5i, which integrates battery modules with a single-phase hybrid inverter, and the standalone PowerNest R5, designed for compatibility with third-party hybrid inverter ecosystems.

Both variants share a wire-free, stackable architecture intended to eliminate inter-module cabling, simplify installation, shorten commissioning time, and reduce the risk of wiring-related errors in the field, according to the company.

Each floor-standing module provides 4.5 kWh of capacity using 170 Ah NFPP sodium-ion cells, delivering a cycle life of up to 8,000 cycles at 25 C under 0.5C/0.5C conditions and 80% depth of discharge. The system operates at 58 V, with 3 kW continuous power output and a maximum current of 55 A per module.

The IP65-rated platform is scalable up to four modules per stack and four stacks in parallel, reaching a maximum stack current of 220 A. It supports a recommended 90% depth of discharge and operates across a wide temperature range from −30 C to 55 C for discharge and −20 C to 55 C for charging.

Each unit weighs 65 kg and measures 670 mm × 420 mm × 250 mm, with RS485, CAN, and USB-C communication interfaces. The system is designed to combine simplified installation, flexible inverter compatibility, and enhanced safety positioning, the company said

Each module integrates a dedicated DC-DC optimizer alongside a custom battery management system, enabling active module-level balancing. Biwatt states that this architecture improves voltage stability, increases usable energy, and maintains more consistent power delivery across varying states of charge.

Safety is supported by the inherent thermal stability of NFPP chemistry and the low-voltage system design, the company said, adding it is currently pursuing UL1973 certification and UL9540A fire safety testing, in addition to existing CE and RCM compliance.

For system operation and maintenance, the platform offers two distinct pathways. When paired with Biwatt inverters, users gain access to remote monitoring, system diagnostics, and over-the-air firmware updates. For field service and troubleshooting, a built-in USB-C interface allows local access to diagnostic data.