Huawei Backup Box-B1 three phase, three-phase back-up module

This is not an inverter, but a switching box. Its role is simple: when the grid power fails, it separates a part of the house — the loads you want to keep running — and supplies them from the battery of the photovoltaic system. It is installed between the hybrid inverter and the distribution board and practically creates a dedicated circuit for the fridge, the lighting, the internet or the heating boiler. Without such a box, a system with panels and a battery stops together with the grid.

Switching is automatic, in less than 3 seconds from the grid failure — fast enough for the fridge, the lights and the heating boiler, but not instantaneous, so a computer without a UPS may reset. The backup output is single-phase, at 220 V / 230 V, and delivers a maximum of 3,300 VA, that is roughly what the fridge, the lighting, the router and a boiler pump consume at the same time; it is not sized for an electric water heater or a hob. The box measures 400 x 350 x 130 mm, weighs 11 kg, has IP65 protection and can be mounted indoors or outdoors, at temperatures between -20 and +45 degrees C. It is configured and monitored from the FusionSolar app, together with the inverter and the LUNA2000 battery. Note: the 3.3 kW figure refers to the power available on the backup output, not to the power of an inverter.

Compatibility: SUN2000-3/4/5/6/8/10KTL-M1 three-phase hybrid inverters. Single-phase backup output 220 V / 230 V, 3,300 VA maximum, 15.2 A rated current; maximum pass-through current on the grid side 40 A; grid voltage 380 V / 400 V three-phase, AC operating range 342-440 V, 50/60 Hz; switching time under 3 s. IP65 enclosure, permissible humidity 0-100% RH.

Who it suits

Suited to a home with a Huawei M1 series three-phase inverter and a LUNA2000 battery, located in an area with power cuts, where only the essential loads are to be kept running.

Terms explained

• Backup (reserve supply): The function through which a part of the house stays supplied from the battery when the electricity grid goes down.
• Pass-through: The current that passes through the box to the house in normal operation, when the grid is present; here up to 40 A.
• Essential loads: The circuits chosen to stay supplied during a cut: usually fridge, lights, internet and the heating boiler.

Technical specifications

Recommended applications

• Residential hybrid systems with backup on essential loads
• Homes with a SUN2000 M1 three-phase inverter and a LUNA2000 battery
• Offices and small commercial spaces with critical loads
• Areas with frequent grid outages

Warranty

2 years (warranty declared by distributors)

Technical details

Specifications confirmed from the manufacturer's datasheet

Huawei Backup Box-B1 is not an inverter, but a switching module for the reserve supply (backup) function of the Huawei three-phase hybrid inverters of the SUN2000-3/4/5/6/8/10KTL-M1 series. It is installed between the inverter and the distribution board and separates the essential loads onto a dedicated circuit, which stays supplied even when the grid goes down.

When the grid is interrupted, switching to battery supply is done automatically, in less than 3 seconds. The backup output is single-phase, 220 V / 230 V, with a maximum power of 3,300 VA and a rated current of 15.2 A. The maximum pass-through current on the grid side is 40 A, the grid voltage 380 V / 400 V three-phase, with an AC operating range of 342-440 V and a frequency of 50/60 Hz.

The IP65 enclosure allows indoor or outdoor mounting; the dimensions are 400 x 350 x 130 mm, the weight 11 kg, the operating temperature -20...+45 C and the permissible humidity 0-100% RH. Configuration and monitoring are done through the FusionSolar app, together with the inverter and the LUNA2000 battery. Note: the 3.3 kW value associated with the product represents the reserve power available on the backup output, not the power of an inverter.