Deye BOS-B256 Pro-A3 battery system257.23kWh 819.2V commercial battery system with 16 modules

Overview

BOS-B256 Pro-A3 is the largest single-cluster configuration of Deye's BOS-B Pro-A3: sixteen 16.08kWh modules in series with one BOS-B-PDU-2-A, for 257.23kWh at 819.2V nominal and 231.48kWh usable. At 180A it delivers up to 147.46kW DC (128.61kW rated). The four-column system measures 2150×1305×800mm and weighs about 2240kg. Deye's configuration note allows 14–16 modules on SUN-125K-SG02HP3-EU-GM10, so a full cluster can run that inverter at rated power.

• 16.08kWh, 314Ah, 51.2V LiFePO4 modules
• 5–16 modules per cluster: 80.38–257.23kWh
• 256–819.2V nominal, 180A charge and discharge
• Up to 16 clusters on one PCS
• Smart fan cooling, indoor IP20 enclosure
• ≥6000 cycles, 10-year warranty

What's in the kit

• 16 × Deye BOS-B-Pack16-A3
• 1 × Deye BOS-B-PDU-2-A

How it works

BOS-B Pro-A3 is a modular high-voltage battery for small commercial and industrial sites, with a range of 80–257kWh per cluster. BOS-B-Pack16-A3 modules of 16.08kWh (314Ah at 51.2V) are stacked on bases in up to four columns and connected in series to a BOS-B-PDU-2-A distribution unit, which holds the BMS, breaker, touch display, Bluetooth and two pairs of PCS outputs.

Five modules give BOS-B80 Pro-A3 at 256V and 80.38kWh; sixteen give BOS-B256 Pro-A3 at 819.2V and 257.23kWh, with a 665.6–934.4V window. Charge and discharge current is 180A for every size, so maximum DC power rises from 46.08kW to 147.46kW with the module count. Deye recommends 90% depth of discharge, for 231.48kWh usable on the largest cluster.

Key features

The modules are cooled by smart-controlled fans and the system supports aerosol fire extinguishing and a fault signal input. The BMS balances the cells, and firmware can be updated by USB or through Deye Cloud. Deye rates the system for at least 6000 cycles at 0.5C to 70% end of life with a 10-year warranty. With Deye PCS and STS modules, clusters scale to 2.3MW/4.1MWh, and five STS modules can parallel twenty 125kW PCS units.

Installation and compatibility

Install the IP20 system indoors on a solid, level floor, more than 5km from the coast (corrosion class C3), at up to 3000m. It may stand against a wall, needs 1m free in front and 300mm to the PCS, and each module needs 112.6m³/h of ventilation. The PDU requires a 200–240V, 3A auxiliary AC supply for the fans. Battery-to-inverter communication cables must stay under 30m.

Deye's configuration note gives the module count per inverter: 5–16 modules for hybrid inverters, 14–16 for PCS on-grid and 15–16 for PCS off-grid use, further limited by MPPT open-circuit voltage. Examples for two hours of storage are 11 modules with SUN-100K-SG02HP3-EU-GM10, 14 with SUN-125K-SG02HP3-EU-GM10 and 10 with SUN-80K-SG02HP3-EU-EM6, each sized so the battery reaches the inverter's rated power.

Monitoring and settings

The PDU display shows state of charge and numbered fault codes, with a yellow light for high voltage on and a red alarm light. Data reach the inverter or EMS over CAN, RS485 or TCP. With Bluetooth the Deye Cloud app reads each module and the whole system locally, and with a Deye inverter with Wi-Fi or a data collector stick the battery appears in Deye Cloud on the inverter's architecture page for remote monitoring.

Questions and answers