Stealth ST-INV-S Series User manual

User Manual
ST-INV-S Series
PV Energy Storage Grid-
connected Inverter
www.stealthenergy.cn VER: 1.2

User Manual
I
About this manual
This manual mainly introduces the product information, installation, operation and maintenance
guidelines of the inverter, and does not include all the information of the photovoltaic system.
You can log on to www.stealthenergy.cn or the website of the equipment manufacturer for more
information.
Scope of application
This manual is applicable to the following models of low-power string photovoltaic grid-
connected inverters:
•
ST-INV-S3.0
•
ST-INV-S3.68
•
ST-INV-S4.0
•
ST-INV-S5.0
Unless otherwise specified, hereinafter referred to as "inverter".
To the reader
This manual is intended for professional technicians who install, operate and maintain the
inverter, as well as end users who need to view inverter information.
Manual use
Please read the manual carefully before using the product, and keep the manual in a place where
it is easily accessible.
The contents of the manual and the pictures, logos, symbols, etc. used are owned by Suzhou
Stealth Energy Technology Co., Ltd. Persons who are not staff of the company are not allowed
to publicly reproduce all or part of the content without written authorization.
The content of the manual will be continuously updated and revised, and users can obtain the
latest version of the manual via www.stealthenergy.cn or through their sales channels.

User Manual
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Change history
Below are the historical changes from previous versions of the manual. The latest
document contains all changes made in previous versions.
V1.2 (2023-02-20)
●Update 9.2 technical data.
PV input: maximum input current (Ad.c.) and maximum short-circuit current (Ad.c.)
V1.1 (2021-10-20)
This version is the first formal version.

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Symbol use
In order to ensure the personal and property safety of users when using the product, and to use
the product more efficiently and optimally, the manual provides relevant safety information,
which is highlighted by the following symbols.
Please take careful note of the meaning of the warning symbols so that you can minimize all
risks.
Symbol Description
High potential risk which, if not avoided, will result in death or
serious injury.
Moderate potential risk which, if not avoided, could result in death
or serious injury.
Low potential risk which, if not avoided, could result in moderate or
minor injury.
Potential risk which, if not avoided, could result in failure of the
equipment in normal operation or property damage.
It emphasizes and complements content, or provides tips on using
the product that can help you solve a problem or save time.
CAUTION
NOTICE

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Table of contents
1Safety instruction 1
1.1 General safety instruction 1
1.2 Inverter 2
1.3 Skill requirements for professional technicians 3
2Product description 4
2.1 PV energy storage grid-connected system 4
2.2 Product introduction 5
2.2.1 Model description 5
2.2.2 Product appearance 5
2.2.3 Dimension and weight 6
2.2.4 LED indicator 6
2.3 Function description 7
2.4 Working mode 8
3Unpacking and storage 11
3.1 Unpacking inspection 11
3.2 Identifying inverter 11
3.3 Shipping list 12
3.4 Inverter storage 12
4Mechanical installation 13
4.1 Installation precautions 13
4.2 Choose the installation site 13
4.3 Installation tools and parts 16
4.4 Installation of inverter 17
5Electrical connection 19
5.1 Terminal introduction 20
5.2 Overview of electrical connection 21
5.3 Ground connection 22
5.4 Grid and Back-up connection 23
5.4.1 AC side requirements 23
5.4.2 Assembling the cable to the AC & Back-up connector 24
5.4.3 Installation of AC connector 25

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5.5 PV string connection 27
5.5.1 PV input device 27
5.5.2 Assembling the cable to the PV connector 29
5.5.3 Installing the PV connector 30
5.6 Battery cable connection 31
5.6.1 Requirements on the battery side 31
5.6.2 Assembling the cable to the Bat connector 32
5.6.3 Installing the Bat connector 33
5.7 WIFI communication connection 34
5.8 Meter connection 34
5.9 DRED connection 36
5.10 BMS connection 37
6Test run 38
6.1 Inspection before test run 38
6.2 Test run steps 38
7Decommissioning, removing and discarding 39
7.1 Decommissioning inverter 39
7.2 Removing inverter 40
7.3 Discarding inverter 40
8Troubleshooting and maintenance 41
8.1 Troubleshooting 41
8.1.1 Troubleshooting displayed in APP 41
8.2 Daily maintenance 44
9 Appendix 45
9.1 Confirmation before contact 45
9.2 Technical data 45
9.3 Quality assurance 48

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1Safety instruction
The inverter is strictly designed and tested in accordance with relevant international safety
standards. As a piece of electrical and electronic equipment, it is necessary to comply with
relevant safety specifications during installation, testing, operation and maintenance.
Unreasonable use or maloperation may result in:
•
Danger to life and personal safety of the operator or third party
•
Damage to the inverter or other property belonging to the operator/third party
In order to avoid casualties, damage to the inverter or other equipment, please strictly adhere to
the following safety precautions. The specific precautions during the operation will be
explained in the corresponding chapters.
1.1 General safety instruction
PV panel
Please follow the various instructions for PV panels.
DANGER
Fatal voltage danger!
Exposure of PV strings to sunlight will generate dangerous voltages.
Since the energy storage battery system may cause the danger of electric shock and short
circuit, in order to avoid possible accidents
, all electrical connections must be completed
only
by professional technicians.
Utility grid
Please follow the connection rules of local grid.
所有
电气连接必须满足当地以及国家电气标准。
仅
在得到当地电力部门许可后，才可将逆变器并入电网。
NOTICE
All electrical connections must meet local and national electrical codes.
The inverter can only be connected to the grid with permission from the local
electric
power
department.

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5min
1.2 Inverter
The warning signs and descriptions on the inverter are shown in the table below:
CE certified.
TUV certified.
RCM certified
Watch out! Potential danger, please do not operate powered on!
After the inverter is disconnected from all external power sources, wait
at least 5 minutes before touching live devices.
The surface is hot, be careful of burns! To avoid burns, do not touch the
surface of the machine while it is running.
Danger of high voltage!
Installation and operation can
only be performed by qualified
professionals.
Please read the manual before performing any operation on the inverter.
The inverter cannot be disposed of together with the household waste.
Disposal information can be found in the enclosed documentation.

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DANGER
Danger of electric shock!
Only the intact and closed enclosure can protect the safety of people and property. Do not
open the enclosure of the inverter when it is working or powered on, otherwise Stealth
Energy will not be held responsible.
WARNING
！Caution
Danger of burns!
When the
inverter
is running, only touch the LED indicator and the DC switch. It is strictly
forbidden to touch the hot parts (such as radiator, etc.) of the
equipment during operation.
Notice
Country selection and protection parameters of the inverter must be set by professional
technicians according to local power grid standards. The wrong country setting may affect
the normal operation of the inverter, causing the inverter to be inconsistent with the
certification in the country.
Touching printed circuit boards or other static-sensitive components may cause damage
to the device.
•Avoid unnecessary circuit board contact.
•Comply with electrostatic protection regulations and wear anti-static wristbands.
1.3 Skill requirements for professional technicians
All installations must be performed only by professional technicians. Professional technicians
must:
•
Receive special training;
•
Read this manual completely and master the operation-related safety matters;
•
Be familiar with local standards and relevant safety codes for electrical systems.
Danger of damage to the inverter or personal injury!
When the inverter is working, it is forbidden to plug or unplug the PV connector,
AC connector and Bat connector.
All safety signs, warning labels and nameplates on the
inverter must be clearly
visible and c
annot be removed or covered.
WARNING

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2Product description
2.1 PV energy storage grid-connected system
ST-INV-S3.0, ST-INV-S3.68, ST-INV-S4.0 and ST-INV-S5.0 are single-phase transformerless
string PV energy storage inverters, as an important part of photovoltaic power generation
system. The inverter converts the DC power generated by the PV panels into AC power that
meets the grid requirements to supply the load, and the rest is charged to the battery and/or fed
into the grid.
The typical application scenarios of the inverter are shown in the following figure.
1. For batteries with attached breaker, the external DC breaker is not necessary.
2. Direction of the CT cannot be connected in reverse, please follow House (K) → Grid (L) direction
for connection.
Fig. 2-1 Application of inverter in photovoltaic power generation system
Model
40A/600V
DC
breaker
32A/230V AC
breaker
50A/230V AC breaker
32A/230V AC
breaker
Depend
on
household
loads
WARNING
The inverter is only suitable for the energy storage grid-connected power generation system
described in this
document.
Since the inverter is a transformerless type, it is required that the positive and negative poles
of the P
V strings cannot be grounded, otherwise the inverter will not run normally.
The shell of the battery system shall be grounded.

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No. Name Description
A PV string
Monocrystalline silicon, polycrystalline silicon, thin-film batteries
that do not need to be grounded.
B
Inverter
ST-INV-S5.0
C
Metering device
Standard metering tool for inverter output energy.
D
Grid
Grounding type: TT, TN.
E
Household loads
Household appliances that consume electrical energy.
F
Important loads
Important loads that cannot be suddenly cut off.
G
Battery system
Battery and BMS system components.
2.2 Product introduction
2.2.1 Model description
Take ST-INV-S5.0 for example:
ST - INV – S 5.0
5.0: Power class code
S: Single-phase
INV: PV grid-connected inverter code
ST: Stealth
Table 2-1 Power description
Model
Rated output
Rated grid voltage
ST-INV-S3.0
3000VA
230Va.c.
ST-INV-S3.68
3680VA
ST-INV-S4.0
4000VA
ST-INV-S5.0
4991VA
2.2.2 Product appearance
The following illustrations are for reference only, please refer to the actual product!
Notice
For TT
-type grids, the neutral-to-ground voltage must be less than 30V.
Do not connect local loads, such as household appliances, lighting and motor loads, between
the inverter and the AC circuit breaker.

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2.2.3 Fig. 2-2 Inverter appearance (ST-INV-S5.0 shown)
D
Fig. 2-3 Inverter size marking (unit: mm)
Model
Width (mm)
Height (mm)
Depth (mm)
Net weight (kg)
ST-INV-S3.0
411 505 195 18.6
ST-INV-S3.68
ST-INV-S4.0
ST-INV-S5.0
2.2.4 LED indicator
As a human-machine interface, LED indicators are located on the front of the inverter. By
observing the flashing color and speed of the indicator, the user can obtain the current working
status of the inverter. Please refer to Table 6-1 for the description of indicator status.
Fig. 2-4 LED indicator
W
H
Dimension and weight

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2.3 Function description
The functions of the inverter can be summarized as follows:
•
Inversion
The inverter converts direct current to alternating current that meets the requirements of the grid
in the region where the inverter is installed and feeds it into the grid.
•
Data storage
The inverter stores system information, such as running information and fault records.
•
Parameter configuration
The inverter provides a variety of parameter configurations to meet various demands or to adjust
its operating performance to its optimal settings. Users can view the information of inverter
through the mobile App. For more professional configuration, please contact Stealth after-sales
service.
•
Communication interface
It can be connected to the WiFi communication data acquisition module to realize the
communication function and connect the monitoring equipment with the entire photovoltaic
energy storage system.
•
Protection
The inverter has protection functions such as short-circuit protection, insulation resistance
grounding monitoring, residual current protection, anti-islanding protection, and DC
overvoltage/overcurrent protection.

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2.4 Working mode
Stealth ST-INV-S3.0, ST-INV-S3.68, ST-INV-S4.0 and ST-INV-S5.0 series, also known as
hybrid or bidirectional solar inverters, are suitable for solar systems with PV, battery, load and
grid systems for energy management. The energy generated by the photovoltaic system is first
used to provide the load, the excess power can be used to charge the battery, and the remaining
power can be used for grid connection. When the PV power is insufficient to meet the
requirements, the battery should be discharged to support the load consumption. If both
photovoltaic power and battery power are insufficient, the system will use grid power to support
the load.
Operation Mode Introduction
Depending on your configuration and layout conditions, PV energy storage systems generally
have the following modes of operation:
MODE _ I Self Use
The energy of the PV system will be first used for local
loads (self-consumption). Excess energy will be used
to charge the battery, and the remaining energy will be
outputted to the grid.
The above introduction describes the general working mode of a photovoltaic system. The
operation mode can be adjusted according to the system layout on the Stealth Cloud App.
The followings are the general
operation modes of photovoltaic energy storage systems.
Notice

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When there is no PV power supply, the battery will
discharge to local loads. When the battery capacity is
insufficient, the grid will provide energy.
MODE _ II Feed-in priority
The energy of the PV system will be first used for
local loads, and then exported to public grid. Excess
power will be used to charge the battery.
When there is no PV to provide energy, the grid or the
battery can provide energy to local loads, depending on
the setting in your application.

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MODE_III Backup mode
The battery can be charged by the grid, and the
charging time/power can be set flexibly on the
application.
MODE_IV Off-grid mode
When the grid is off, the system will provide
energy to important loads through PV or battery.
(Battery is required in EPS mode.)
Notice
In the case of grid connection, all working modes work normally when the battery
SOC > 10%. When the battery
SOC < 10%, the PV or Grid will first charge the
battery to SOC
15%, and then return to the working mode selected by the user.

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Please read the instructions before performing
any operation on the inverter.
The inverter cannot be disposed of together with
the household waste.
3Unpacking and storage
3.1 Unpacking inspection
The inverter has been completely tested and strictly inspected before leaving the factory, but
damage may still occur during transportation. Please conduct a detailed inspection before
signing for the product.
•
Check the packing box for damage.
•
According to the packing list, check whether the goods are complete and in accordance with
the order.
•
Unpack and check whether the internal equipment is in good condition.
If you find any damage, please contact the shipping company or the after-sales service of Stealth
directly, and provide photos of the damage, so as to obtain the fastest and best service.
Do not discard the original packaging of the inverter. It is best to store the inverter in the original
box after it is out of service and removed.
3.2 Identifying inverter
The nameplate of the inverter is attached to the side of the body.
After the inverter is disconnected from all
external power sources, wait at least 5 minutes
before touching live devices.
5min
The surface is hot, be careful of burns! To avoid
burns, do not touch the surface of the machine
while it is running.
CE certified
Fig. 3-2 Inverter
nameplate
Table 3-1 Description of nameplate
TÜV certified
Watch out for danger, please do not operate with
electricity!
Icon Description

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3.3 Shipping list
3-3 Shipping list
a) Unless otherwise specified, the inverter diagrams in this document are illustrations for ST-
INV-S5.0.
b) Documentation includes quick use manual, certificate of conformity, packing list and
product test report.
c) The WiFi communication module may be standard or optional, subject to the actual
delivery.
3.4 Inverter storage
If the inverter is not immediately put into operation, the inverter needs to be stored in specific
environmental conditions:
•
Repack in the original box, keep the desiccant.
•
Storage temperature range: -25℃~60℃, relative humidity range: 0~100%, no
condensation.
•
The maximum number of stacked layers of multiple inverters does not exceed 8.
•
The packing box cannot be tilted or inverted.
a
Inverter (×1)
b
Documentation
Expansion bolt (a set of
M6*60)
M5*10 bolt (×2) M6*10 bolt (×1)
PV connector (2sets)
Battery connector (1 set)
Electricity meter (×1)
c
Communication module
(×1)