HUAWEI Backup Box Alternergy User Guide

: June 13, 2024
: Huawei

Table of Contents

Backup Box Alternergy
Product Information
Product Usage Instructions
2. Device Installation

Backup Box Alternergy

Product Information

The Backup Box is a device used in a residential rooftop PV
plant system to control the inverter grid-tied or off-grid state.
It functions by switching to the off-grid state and supplying power
to off-grid loads in backup mode when the grid fails. When the grid
recovers, the inverter switches back to the grid-tied state.

Model Number: Backup Box

No.	Meaning	Value
1	Product name	Backup Box
2	Design code	B0: single-phase

B1: three-phase

System Networking: The Backup Box is part of a
grid-tied system of a rooftop PV plant which consists of PV
strings, an energy storage system (ESS), an inverter, a Backup Box,
a management system, an AC switch, and a power distribution
unit.

Supported Grid Types: The Backup Box supports
the following grid types: TN-S, TN-C-S, and TT. Note that when the
inverter is in three-phase, three-wire mode, the Backup Box does
not support off-grid operation.

Appearance: The Backup Box features a front
panel, a lock, a hanging kit, a grid AC port (GRID), a COM port
(COM), a ground point, an off-grid load port (BACKUP LOAD), an
inverter AC port (INVERTER AC), a ventilation valve, and an
off-grid load switch.

Product Usage Instructions

2. Device Installation

2.1 Installation Requirements

When installing the Backup Box outdoors, avoid direct sunlight.
It is recommended to install it in a sheltered place or install an
awning over it.
An surge protective device (SPD) needs to be installed on the
grid side of the Backup Box.
When drilling holes for installation, make sure to avoid water
pipes and power cables buried in the wall.

2.2 Installing a Backup Box

The Backup Box comes with M6x60 expansion bolts for
installation. If the length and number of bolts do not meet the
installation requirements, prepare M6 stainless steel expansion
bolts on your own.

The expansion bolts delivered with the inverter are mainly used
for solid concrete walls. For other types of walls, prepare bolts
yourself and ensure that the wall meets the load bearing
requirements of the inverter.

In residential areas, do not install the inverter on drywalls or
walls made of similar materials with weak sound insulation
performance, as the noise generated by the inverter can be
noticeable.

Backup Box-(B0, B1)
Quick Guide
Issue: 04 Date: 2023-02-15

1. The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute a warranty of any kind, express or implied.
2. Before installing the device, read the user manual carefully to get familiar with product information and safety precautions.
3. Only certified electricians are allowed to operate the device. Operation personnel must wear proper personal protective equipment (PPE).
4. Before installing the device, check that the package contents are intact and complete against the packing list. If any item is missing or damaged, contact your dealer.
5. The device damage caused by the violation of instructions in this document is not covered under warranty.
6. The cable colors involved in this document are for reference only. Select cables in accordance with local cable specifications.

1 Overview

Function
The Backup Box is used in a residential rooftop PV plant system to control the inverter grid-tied or off-grid state. When the grid fails, the inverter switches to the off-grid state and supplies power to off-grid loads in backup mode. When the grid recovers, the inverter switches back to the grid-tied state.

Model Number

No. Meaning

Value

1

Product name Backup Box: Backup Box

2

Design code

B0: single-phase

B1: three-phase

System Networking
The grid-tied system of a rooftop PV plant consists of PV strings, an energy storage system (ESS), an inverter, a Backup Box, a management system, an AC switch, and a power distribution unit.

1

· Off-grid electric motor loads are not supported. The startup power of an electric motor is several times of its rated power, which may exceed the load capacity of the Backup Box, resulting in startup failure.
· The off-grid load port cannot be directly connected to the power grid. Otherwise, the off-grid function is unavailable, causing shutdown upon overload.
· The power of off-grid loads cannot exceed the maximum off-grid output power of the inverter.
Supported Grid Types
The Backup Box supports the following grid types: TN-S, TN-C-S and TT. When the inverter is in three-phase, three-wire mode, the Backup Box does not support off-grid operation.
2

Appearance

(1) Front panel (3) Hanging kit (5) Grid AC port (GRID) (7) COM port (COM) (9) Ground point

(2) Lock (4) Off-grid load port (BACKUP LOAD) (6) Inverter AC port (INVERTER AC) (8) Ventilation valve

(10) Off-grid load switch

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2 Device Installation
2.1 Installation Requirements
1. When a Backup Box is installed outdoors, avoid direct sunlight. You are advised to install it in
3a sheltered place or install an awning over it.
2. A surge protective device (SPD) needs to be installed on the grid side of the Backup Box.
Installation Space Angle
Mounting Holes and Dimensions
When drilling holes, avoid the water pipes and power cables buried in the wall.
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2.2 Installing a Backup Box
M6x60 expansion bolts are delivered with the Backup Box. If the length and number of the bolts do not meet installation requirements, prepare M6 stainless steel expansion bolts by yourself.
The expansion bolts delivered with the inverter are mainly used for solid concrete walls. For other types of walls, prepare bolts by yourself and ensure that the wall meets the load bearing requirements of the inverter.
In residential areas, do not install the inverter on drywalls or walls made of similar materials which have a weak sound insulation performance because the noise generated by the inverter is noticeable. Level
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3 Electrical Connection
3.1 Preparations

Connect cables in accordance with local installation laws and regulations. Before connecting cables, ensure that the circuit breaker on the Backup Box and all the
switches connecting to the Backup Box are set to OFF position. Otherwise, the high voltage of the Backup Box may result in electric shocks. After opening the device panel of the Backup Box, remove the shockproof foam. Otherwise, the circuit breaker cannot work properly. If the external AC switch can perform earth leakage protection, the rated leakage action current should be greater than or equal to 100 mA. If multiple SUN2000s connect to the general residual current device (RCD) through their respective external AC switches, the rated leakage action current of the general RCD should be greater than or equal to the number of SUN2000s multiplied by 100 mA. The rated input voltage of the Backup Box is 220 V/230 V (single-phase) or 380 V/400 V (three-phase). If the device runs in a weak power grid area, a self-recovery overvoltage/undervoltage protector needs to be installed at the upstream of the X2 AC power grid input terminal of the Backup Box. This ensures that the device can be disconnected from the power grid when the power grid voltage is abnormal, preventing damage.

Prepare cables based on site requirements.

No. Cable

Type

1 PE cable

Single-core outdoor copper cable

2

Off-grid load output power cable

Outdoor copper cable

3

Grid AC output power cable

Outdoor copper cable

4

Inverter AC input power cable

Outdoor copper cable

5 Signal cable

Two-core outdoor shielded twisted pair cable

Conductor CrossSectional Area Range

Outer Diameter

410 mm2

N/A

46 mm2

1021 mm

46 mm2

1021 mm

46 mm2

1021 mm

0.201 mm2

48 mm

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3.2 Installing a PE Cable
Do not connect the neutral wire to the enclosure as a PE cable. Otherwise, electric shocks may occur.

Ground point
3.3 Installing an Output Power Cable for Off-Grid Loads

Before installing a cable, open the panel of the Backup Box, route the cable through the off-grid load port, and connect the cable. After all cables are connected, reinstall the panel.

Off-Grid Load Terminal (X1)

No..

1

2

34

Single-Phase

L N – PE

Off-Grid Load Terminal (X1)

No..

1

2

3

4

Three-Phase L

N

–

PE

X1 Strip the cable to the wiring port
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3.4 Installing a Grid AC Output Power Cable

Connecting Grid AC TerminalsX2

No.

1

Single-Phase L

23

–

4

5

N

–

6

7

PE –

Connecting Grid AC TerminalsX2

No.

1

2

3

4

5

Three-Phase

L1 L2 L3 N

–

6

7

PE –

X2
Strip the cable to the wiring port

If multiple inverters are connected in parallel, the connection of AC power cables L1, L2, and L3 on the power grid side of the Backup Boxes connected to each inverter must be the same.

3.5 Installing an Inverter AC Input Power Cable

Connecting AC Input Terminals of the InverterX3

No.

1 2 3 4 5 6 7 8 9 10 11

Single-Phase – L – – – N – – – PE –

Connecting AC Input Terminals of the InverterX3

No.

1 2 3 4 5 6 7 8 9 10 11 12 13

Three-Phase L1 – L2 – L3 – – N – – – PE –

8

X3
Strip the cable to the wiring port

The sequence of connecting the cables to a single-phase Backup Box and to the AC terminals L, N, and PE on the inverter must be the same. The sequence of connecting the cables to a threephase Backup Box and to the AC terminals L1, L2, and L3 on the inverter must be the same. Otherwise, the device cannot work properly. (As shown in the following figures, connect the cables to a single- phase Backup Box in the sequence of L, N, and PE from left to right, and connect the cables to a three-phase Backup Box in the sequence of L1, L2, and L3.)

Backup Box-side terminal (single-phase)

Inverter-side terminal (single-phase)

Backup Box-side terminal (three-phase)

Inverter-side terminal (three-phase)

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3.6 Installing a Short-Circuiting Plate
· When installing a short-circuiting plate, ensure that it is inserted into the correct port and securely installed to avoid short circuits caused by incorrect installation.
· If no short-circuiting plate is installed, the neutral wire will be suspended in off-grid mode, but the off-grid/grid-tied switching function is not affected. You are advised to install a short-circuiting plate according to the local power grid standard.
Neutral Wire Connected
If the neutral wire cannot be disconnected from the power grid in off-grid mode (such as in Australia), insert the short-circuiting plate between 4 and 5 of the AC terminal X2 according to the local power grid standard.
The short-circuiting bar delivered with the product is bound to the ground cable inside the chassis.
Power grid AC terminal X2 (Single-Phase/Three-Phase)
Neutral Wire Disconnected
If the neutral wire needs to be disconnected in off-grid mode (such as in German), according to the local power grid standard, insert the short- circuiting plate between 10 and 11 of the AC terminal X3 for the single-phase Backup Box. Insert the short-circuiting plate between 12 and 13 of the AC terminal X3 for the three-phase Backup Box.

Inverter AC terminal X3 (single-phase)
3.7 Installing Signal Cables
Communications Terminal Definition

Inverter AC terminal X3 (three-phase)

No. Label Definition

Note

1 DI Digital input signal+ Connects to the positive pole of the DI port and functions as the port for the Backup Box to send feedback signals.

2 GND GND of the DI port Connects to the GND of the DI port.

10

X4

Strip the cable to the wiring port

3.8 Connecting Signal Cables on the Inverter Side

SUN2000-(2KTL-6KTL)-L1

COM port (COM)

Inverter AC

COM Port Pin Definitions

No. Label
5 GND 8 DI2

Definitio n
GND
Digital input signal 2+

Description
Connects to the GND of the DI2 port. Connects to the positive terminal of DI2 and functions as the port for the Backup Box to send feedback signals.

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SUN2000-(3KTL-12KTL)-M1

COM port (COM)

Inverter AC

COM Port Pin Definitions

No. Label Definition 8 DIN1 Digital input
signal 1+
16 GND GND

Note
Functions as the port for the Backup Box to send feedback signals.
Connects to the GND of DIN1.

4 Verifying the Installation

No. Acceptance Criteria

1

The installation is correct and reliable.

2

Cables are routed properly as required by the customer.

3

Cable ties are secured evenly and no burr exists.

4

The PE cable is connected correctly, securely, and reliably.

5

The switch of the Backup Box and all the switches connected to it are OFF.

6

Cables are connected correctly and securely. Use a phase sequence meter to check

whether the cables on the grid side are connected correctly.

7

Unused terminals and ports are locked by watertight caps.

8

The installation space is proper, and the installation environment is clean and tidy.

5 Powering On the System
1. Use a multimeter to check whether the AC voltage in the power distribution box (PDB) is within the allowed range and whether cables are correctly connected.
2. Turn on the PDB AC switch between the Backup Box and the power grid. (Ensure that the load switch of the Backup Box is OFF.)
3. Check whether the cable connection of the grid AC terminals is correct. 4. (Optional) Remove the locking screw beside the DC switch on the inverter. 5. Turn on the DC switch (if any) between the PV strings and the inverter. 6. Turn on the DC switch at the bottom of the inverter. 7. Check that the off- grid load power does not exceed the off-grid output power allowed by
the inverter.

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8. After ensuring that the load circuit is normal, turn on the AC switch of the Backup Box. 9. Observe the LED indicators on the front of the inverter to check the running status of the
inverter.

Category
Running indication

Status (Blinking orange at long intervals , On for 1s and then Off for 1s)

Definition N/A

Steady green
Steady orange
Blinking orange at long intervals
Blinking orange at long intervals

Steady green Steady orange Off

On-grid Backup Standby in backup mode

Blinking orange at long Overload in backup mode intervals

If the off-grid load is overloaded, indicators and on the inverter blink orange slowly. Reduce the off-grid load power and manually clear the alarm or until the inverter is recovered. The inverter attempts to restart at an interval of 5 minutes. If the inverter fails to restart for three times, the interval changes to 2 hours. If the inverter is standby in off-grid mode, check the inverter alarms and rectify the fault.
6 System Commissioning

During system deployment, the AC power supply needs to be connected to ensure that the offgrid/grid-tied switching function of the Backup Box can be verified.
Download and install the latest version of the FusionSolar app by referring to the quick guide for the corresponding inverter model or the FusionSolar App Quick Guide. Register an installer account and create a plant and owner (skip this step if an account has been created). You can scan the QR code to obtain the FusionSolar App Quick Guide.
Parameter Settings
Open the FusionSolar app, log in to intl.fusionsolar.huawei.com using the installer account, choose My > Device Commissioning, and connect to the WLAN hotspot of the solar inverter. On the home page, choose Setting > Feature parameters to set the off-grid/grid-tied control parameters.

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Parameter Settings

Value

Off-grid mode

If this parameter is enabled, the Backup Box switches to the off-grid mode when the grid fails. This parameter can be set only when the Backup Box is configured. If the Backup Box is not configured, this parameter cannot be enabled. Otherwise, an alarm is generated.

Enable Disabled
(default)

Backup power SOC

Sets the backup power SOC. In grid-tied mode, the battery does not discharge when it is discharged to the backup power SOC. When the grid fails, the battery supplies power to loads in off-grid mode until it reaches the end- ofdischarge capacity.

[20%, 100%] Default value: N/A

Grid-tied/Offgrid mode switching

If this parameter is set to Automatic switching, the system switches to the off-grid mode when the grid fails, and switches to the grid-tied mode when the grid recovers. If this parameter is set to Manual switching, you need to log in to the app and connect the inverter to enable the off-grid mode when the grid fails.

Automatic switching (default)
Manual switching

Verifying the Off-grid/Grid-tied Switching Function
1. Power on the Backup Box according to the power-on procedure, wait for the inverter to connect to the power grid, and log in to the app to enable Off- grid mode.
2. Turn off the AC switch in the PDB between the Backup Box and the power grid, and check whether the off-grid output is normal. The inverter indicators and are steady orange. (If the AC switch between the inverter and the Backup Box is turned off, the off-grid switching is not triggered and the inverter is in off-grid standby mode.)
3. Turn on the AC switch in the PDB between the Backup Box and the power grid. The inverter indicators and blink green slowly until the inverter is connected to the power grid.
7 Routine Maintenance
To ensure the long-term and proper running of the system, you are advised to perform routine maintenance on the Backup Box periodically. 1. Check the system cleanliness, system running status, electrical connection, and grounding reliability every half year. 2. Check whether the off-grid/grid-tied switching function is normal each quarter.
8 Troubleshooting
1. Backup Box checking solution: After arriving at the site, the personnel can check whether the Backup Box is damaged as follows:
a. It is recommended that loads be disconnected before checking. b. Use a multimeter to check the connectivity between the Backup Box terminals, as shown
in the following tables.

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9 Product Specifications Single-Phase Backup Box

Wiring Requirements

Detection Terminal

No. Circuit Breaker Grid (QF)

Inverter

X4-1 & X4-2 COM-1 & COM-2

X2-1 & X3-2 GRID-L & INVERTER-L

X3-6 & X3-10 INVERTER-N & INVERTER-PE

X2-1 & X1-1 GRID-L & LOAD-L

X3-6 & X1-2 INVERTER -N & LOADN

1 On

Power off

Shutdown

Connected

Disconnected Disconnected Disconnected Connected

2 On

Power on

Shutdown

Disconnected

Connected

Disconnected Connected

Connected

3 On

Power Off-grid off output

Connected

Disconnected Connected Disconnected Connected

Three-Phase Backup Box

Wiring Requirements

Detection Terminal

No. Circuit Breake Grid
r (QF)

Inverter

X4-1 & X4-2 COM-1 & COM-2

X2-1 & X3-1 X3-3 & X3-8

X2-1 & X1-1

GRID-L1 & INVERTER-L2 GRID-L1 &

INVERTER-L1 & INVERTER-N LOAD-L

X3-3 & X1-2 INVERTER-L2 & LOAD-N

1 On 2 On

Power off

Shutdown

Connected

Disconnected Disconnected

Power on

Shutdown

Disconnected

Connected

Disconnected

Disconnected Disconnected Connected Disconnected

3 On

Power Off-grid off output

Connected

Disconnected Connected

c. If the conduction status of an item is inconsistent with that in the tables, the Backup Box is damaged.
2. If the mains recovers but the inverter still works in off-grid state (LED1 and LED2 are steady orange), contact the customer service personnel or dealer for repair.
3. If the off-grid mode is enabled when no Backup Box is connected, an alarm indicating that the Backup Box is abnormal is reported when the AC power supply is disconnected. In this case, the fault cannot be rectified. The fault is rectified only after the inverter and battery are powered off.
4. If the Backup Box is used for the first time and is not used later, you must disable the offgrid mode when the inverter is running properly. Otherwise, you need to power on the inverter again and modify the settings.
5. If the single-phase Backup Box generates abnormal noises during repeated switching, check whether the inverter AC terminal is reversely connected to the power grid AC terminal.
6. If the AC contactor KM3 of the Backup Box repeatedly switches on and off and generates abnormal sound, check whether the off-grid load is too high.

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9 Customer Service Contact Information

Customer Service Contact

Region

Country

France

Germany

Spain

Europe

Italy

UK

Netherlands

Other countries

Australia

Turkey

Service Support Email
eu_inverter_support@huawei.com
For details, see solar.huawei.com. eu_inverter_support@huawei.com eu_inverter_support@huawei.com

Malaysia

Asia Pacific

Thailand

apsupport@huawei.com

Japan India South Korea
North America

China

solarservice@huawei.com

Other countries Japan India South Korea USA Canada

apsupport@huawei.com Japan_ESC@ms.huawei.com indiaenterprise_TAC@huawei.com Japan_ESC@ms.huawei.com eu_inverter_support@huawei.com eu_inverter_support@huawei.com

Mexico

Argentina Latin America
Brazil Chile Other countries

la_inverter_support@huawei.com

Egypt

Middle East and Africa

UAE

South Africa Saudi Arabia

eu_inverter_support@huawei.com

Pakistan

Morocco

Other countries

Phone
0080033888888
1800046639 N/A 0080021686868 /1800220036 (+66) 26542662 (charged by local call) 1800290055 (free in Thailand)
400-822-9999 0060-3-21686868 0120258367 1800 103 8009 N/A 1-877-948-2934 1-855-482-9343 018007703456 /0052-442-4288288 0-8009993456 0-8005953456 800201866 (only for fixed) 0052-442-4288288 08002229000 /0020235353900
08002229000
0800222900
8001161177
0092512800019
0800009900
0020235353900

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