Huawei MERC-1100W-P User manual

HUAWEI DIGITAL POWER TECHNOLOGIES CO., LTD.
MERC-(1300W, 1100W)-P Smart PV Optimizer
Quick Guide
Issue: 03
Part Number: 31500HND
Date: 2022-11-30

1
Type II apparatus
(enhanced insulation)
Burn warning
Electric shock
warning
EU waste electrical and electronic
equipment (WEEE) mark
Refer to
documentation
Copyright © Huawei Digital Power Technologies Co., Ltd. 2022.
All rights reserved.
1. The Smart PV Optimizer is a DC-DC converter installed on the rear of PV modules in a PV
system. It manages the maximum power point (MPP) of each PV module to improve the
energy yield of the PV system, and performs functions such as module-level shutdown and
module-level management.
2. An optimizer is delivered with two types of input power cables: long (1300 mm) or short
(100 mm) cables. For PV modules with long cables, select optimizers with short cables; for PV
modules with short cables, select optimizers with long cables.
1Product Overview
Short Input Power Cables Long Input Power Cables
2Installing the Device
Installation Requirements
2.1
Clearance
PV modules
Mounting
bracket

2
PV modules
3. Improper installation and operations of optimizers
may cause fire. Do not store flammable or
explosive materials in the installation area.
4. Do not cut the cables delivered with
the optimizers. Otherwise, the
warranty will be voided.
5. Avoid direct sunlight.
2. Do not install optimizers in positions
that may be submerged in water.
Water
Cable
cutter
Ventilation area
Rooftop (color steel tile)
1. If optimizers and PV modules are installed close to the rooftop (for example, color steel tile
rooftop), ensure that the optimizers are well ventilated. It is recommended that the ambient
temperature be less than or equal to 70℃. If the ambient temperature exceeds 70℃, the
optimizers may shut down for overtemperature protection. After the operating temperature
decreases, the optimizer automatically recovers with no risk of damage.

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Properly plan the installation position of optimizers to ensure that the cables between the optimizer
and the PV module and between adjacent optimizers can be properly connected, and the maximum
communication distance between the optimizer and the solar inverter is within 350 m.
Note: Use a
marker to mark
information on the
physical layout
template if needed.
Installing the Optimizer
2.2
Solar inverter
1. Select optimizers based on the installation scenario.
•For PV modules with long power cables, select optimizers with short input power cables. The
PV modules can be installed vertically or horizontally.
•For PV modules with short power cables, select optimizers with long input power cables. The
PV modules can be installed only vertically.
2. After determining the installation position of the optimizer, remove the SN label from the
optimizer and attach it to the physical layout template. For details, see instructions on the
back of the physical layout template.

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Flange nut
Installed on an Extruded Aluminum
Profile –T-shaped Bolt
M8x20 T-shaped bolt
Extruded
aluminum
profile
The optimizer is mounted to an
aluminum profile on the front or rear
side with T-shaped bolt and nut.
The T-shaped bolt and nut need to be
purchased separately from Huawei.
The bolt dimensions are as follows.
Installed on a PV Module
Frame –Bolt Assembly
M8x20 bolt assembly
Flange nut
Before installation, ensure that a
mounting hole has been reserved
on the PV module frame.
The bolt assembly and nut need to
be purchased from a third party.
Ensure that the length meets the
installation requirements of the PV
module frame.
PV module
3. Install the optimizer based on the selected installation mode.
Installed on a PV Module
Frame –Frame Mounting Bracket
Do not press the optimizer mounting
bracket against the positioning pole
of the frame mounting bracket.
Purchase the frame mounting
bracket separately from Huawei.
Install the PV module after the
optimizer is installed.
PV module
Frame mounting bracket

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3Installing the Optimizer Cables
1. Connect the optimizer
input (IN) cable to
the PV module
connection box.
2. Connect the positive probe of the multimeter to the positive
output terminal of the optimizer and the negative probe to the
negative output terminal. Check the output voltage of a single
optimizer.
Ensure that the input (IN) and output (OUT) cables of the optimizer are correctly connected. If
they are reversely connected, the device may be damaged.
The typical value
of V1 is 1 V.
Voltage
Cause
Suggestion
0.95 V ≤ V1 ≤ 1.05 V
The optimizer is normal.
-
V1
> 1.05 V
The
optimizer is faulty.
Replace
the optimizer.
V1 < 0.95 V
The irradiance is low.
The optimizer input
power cables are not
connected.
The optimizer cables
are incorrectly
connected.
The optimizer is faulty.
1. Measure the voltage when the irradiance is
adequate.
2.
Connect the optimizer input power cables.
3.
Correct the optimizer cable connections.
Connect the optimizer input power cables
to the PV module output power cables.
4.
If the voltage is still abnormal, replace the
optimizer.
V1 ≈
–1 V
The probes are reversely
connected.
Reconnect the positive and negative probes
correctly.
3. Check that the optimizer and its input cables are properly connected, and then connect the
optimizer output power cables. Measure the PV string voltage when the sunlight is sufficient.
Configuration Scenarios
PV string

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To minimize electromagnetic interference,
ensure that the distance between the positive
and negative cables of an optimizer is
minimized.
To ensure reliable communication between the
inverter and optimizers, the AC and DC power
cables of the inverter must be more than 10 cm
away from the AC power cables of motor-type
impact loads, such as air conditioners and
elevators. It is recommended that the cables be
routed in different troughs or pipes.
For details about how to configure PV strings
with optimizers connected to the inverter, see
section 2.3 "Configuration Principles" in the
user manual. Incorrect configurations may
cause serious consequences.
Note: The figure shows only the output
(OUT) cables.
Voltage
Cause
Suggestion
The
PV string
voltage is 0.
The PV string is open-circuited.

The cables are not connected to the
same PV string.
1.
Check whether the PV string is open-
circuited.
2.
Identify the string cables correctly.
The PV string
voltage is a
negative value.
The probes are reversely connected.
The cable labels are incorrect.
1.
Reconnect the positive and negative
probes correctly.
2.
Prepare cable labels correctly.
The value of PV
string voltage
is less than the
number of
optimizers.

Some optimizer input power cables
are not connected.
Some optimizer output power
cables are not connected.
Some optimizer output power
cables are reversely connected.
Check whether PV modules and PV
string cables are correctly connected.
The value of PV
string voltage
is greater than
the number of
optimizers.
The actual number of optimizers in
the string is greater than expected.
PV modules are directly connected
to PV strings without being
connected to optimizers.
1.
Check whether the number of
optimizers in the PV string is correct.
2.
Check whether PV modules and PV
string cables are correctly connected.
4. Connect cables between the PV string and the solar inverter.

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4Power-On Commissioning
1. The physical layout of the optimizers must be provided so that you can easily
locate faulty optimizers based on the physical layout diagram.
2. The physical layout of the optimizers must be provided to use the optimizer
disconnection detection function. After optimizer disconnection detection is
performed, the locating result can be viewed on the Layout screen.
3. Choose Maintenance > Subdevice management > Auto search to add an
optimizer. For details about the physical layout of optimizers, see the MERC
Smart PV Optimizer User Manual or FusionSolar App Quick Guide . You can
scan the QR code to obtain the FusionSolar App Quick Guide .
If changes occur in the system, such as adding, deleting, and replacing an optimizer, adjusting
the physical position of an optimizer, or adjusting the PV string connected to the solar inverter
input, turn off the DC and AC switches of the inverter and wait for 5 minutes before performing
the operation to avoid personal injuries. After the change is performed, the optimizer search
process must be performed again and the physical layout diagram must be updated. Otherwise,
the networking is incomplete, optimizer faults cannot be located, or the system fails.
1. Open the FusionSolar app, log in to intl.fusionsolar.huawei.com using the installer account,
choose Me > Device commissioning, and connect to the WLAN hotspot of the solar inverter.
2. Select installer and enter the login password. Tap Log In. The device commissioning screen is
displayed.
3. Choose Device monitoring, select the PV string and check the optimizer status.
5Troubleshooting
Optimizer status
Status
Description
Green
The optimizer is running properly.
Gray
The optimizer is offline.
Check that the SN and
location information are correct and search for the
device again.
Red
The optimizer is faulty.
Yellow
The optimizer is disconnected.

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Alarm
Cause
Suggestion
Input overvoltage
Optimizer input
overvoltage
occurred.
Check whether the open
-circuit voltage of the PV module
exceeds the maximum input voltage of the optimizer.
Overtemperature
protection
The optimizer
internal
temperature is too
high.
1.
Check the ventilation and ambient temperature at the
optimizer installation position. If the ventilation is poor
or the ambient temperature exceeds the upper
threshold, improve the ventilation and heat dissipation.
2. If the ventilation and ambient temperature are normal,
contact your installer.
Internal
hardware fault
An internal fault
occurred in an
optimizer.
Contact your installer.
Output terminal
overtemperature
The output
terminal
temperature of
some optimizers is
abnormal.
Contact your installer to replace the faulty optimizer and
the optimizer connected to the short output
cables of the
faulty optimizer.
Output backfeed
Optimizer output
backfeed occurred.
1. Check whether PV modules are shaded when PV
strings are connected in parallel.
2. If the fault persists, contact your installer.
Abnormal output
voltage
The optimizer
output voltage is
abnormal.
1. When the irradiance is normal, perform optimizer
search again.
2. Check the voltage of the corresponding PV string. If
the voltage is greater than 0 V, power off the system
and check whether the extension cable of the
abnormal optimizer is correctly connected.
3. Check the voltage of the corresponding PV string. If
the voltage is 0 V, power off the system and check the
cable connection of the PV string. If there is an open
circuit, rectify the cable connection of the PV string. If
the polarity is incorrect, reconnect the PV string in the
correct polarity. After the open circuit or reverse
polarity is rectified, power on the system and perform
an optimizer search again. If the alarm persists, check
whether the extension cable of the abnormal
optimizer is correctly connected.
4. If the fault persists, contact your installer.
Note: The polarity at both ends of the extension cable
must be opposite (one end is a positive connector, and
the other is a negative connector). To determine the PV
string polarity, see "3 Installing the Optimizer Cables."
Upgrade failed
The optimizer
software upgrade
failed.
1. When the irradiance is normal, perform the optimizer
upgrade again.
2. If the fault persists, contact your installer.

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6Replacing an Optimizer
1. Power off the solar inverter and remove the faulty optimizer.
2. Install a new optimizer and correctly connect its cables.
3. Power on the solar inverter. Log in to the FusionSolar app and tap the plant name on the
Home screen to access the plant screen. Choose Devices > Inverter, select the inverter
corresponding to the faulty optimizer, tap Optimizer Search, and perform operations as
prompted to search for optimizers.
4. Choose Devices > Connected devices > Optimizer, tap Optimizer No., select the faulty
optimizer, tap Device Replacement, and replace the optimizer as prompted.
If
N optimizers need to be replaced, perform the preceding procedure for N times.
After the optimizer is replaced, the new optimizer automatically inherits the energy yield,
physical layout, and logical layout of the faulty optimizer.

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The optimizer uses Staubli MC4 DC connectors. Ensure that the DC connectors to be connected
are of this model. If the DC connectors to be connected are not of the Staubli MC4 model, the
connector compatibility report and third-party lab (TUV, VED, or Bureau Veritas) report from
the DC connector manufacturer must be available. Using incompatible DC connectors may
result in serious consequences. The resulting device damage is beyond the warranty scope.
Optimizers are not supported in off-grid scenarios.
Partial configuration is not allowed. All PV modules must be connected to optimizers.
Otherwise, serious consequences may occur, and the resulting device damage is not covered by
the warranty.
7Precautions
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.
Only qualified and trained electrical technicians are allowed to operate the device. Operation
personnel should understand the composition and working principles of the grid-tied PV
power system and local regulations.
Carefully read this document prior to installation to get familiar with product information
and safety precautions. Huawei shall not be liable for any consequence caused by violation of
the storage, installation, and operation regulations specified in this document and the solar
inverter user manual.
Use insulated tools when installing the device. For personal safety, wear proper personal
protective equipment (PPE).
If an optimizer does not connect to any other device, connect the OUT+ and OUT–ports of
the optimizer respectively to the IN+ and IN–ports to protect the terminals from water.
It is recommended that the positive and negative cables (PV+/PV–) between the optimizer
and the solar inverter be placed side by side to avoid cable winding.
The input end of the optimizer should be connected to the PV module connection box, and
the output end to the adjacent optimizer or a solar inverter. Do not reversely connect the
input and output cables. Otherwise, the optimizer may be damaged.
The screenshots are for reference only. The actual screens may vary. For details about the
physical layout of optimizers, see the MERC Smart PV Optimizer User Manual or FusionSolar
App Quick Guide .

Huawei Digital Power Technologies Co., Ltd.
Huawei Digital Power Antuoshan Headquarters, Futian
Shenzhen 518043, People's Republic of China
solar.huawei.com