LET-XB2-HJ Series MPPT Solar Charge Controller

Specifications

• Brand: Lesso Group
• Stock Code: 2128.HK
• Model: LET-XB2-HJ Series
• Type: MPPT Solar Charge Controller

Product Information

The LET-XB2-HJ Series MPPT Solar Charge Controller is designed
to efficiently regulate and control the charging of solar panels to
batteries. It is manufactured by Guangdong Lesso Energy Storage
Technology Co., Ltd.

Product Usage Instructions

Important Safety Instructions

It is crucial to follow these safety instructions to ensure safe
and proper operation of the solar charge controller:

• Keep the manual for future reference.
• Do not attempt to disassemble or repair the controller.
• Install the controller indoors in a well-ventilated place.
• Avoid harsh environments like humid, salt spray, corrosive
  areas.
• Disconnect PV array connections and battery fuses before
  installation.
• Ensure tight wiring connections to prevent heat
  accumulation.
• Installation and operation should be done by professional
  personnel.

Symbols Explanation

To understand the safety information in the manual, pay
attention to the following symbols:

• DANGER: High-level hazard leading to serious
  injury or death.
• WARNING: Medium-level hazard that could result
  in serious injury or death.
• CAUTION: Low-level hazard that could result in
  minor or moderate injury.
• NOTICE: Important reminders during operation
  to prevent equipment errors.
• Tip: Recommendations for reference.

FAQ

Q: What should I do if the controller is exposed to a harsh
environment?

A: It is strictly advised not to install the controller in
humid, salt spray, corrosive, greasy, flammable, explosive, dust
accumulative, or other harsh environments as it may lead to damage
and void the warranty.

Q: Can I repair the controller myself if an issue arises?

A: No, there are no user-serviceable components inside the
controller. Do not attempt to disassemble or repair it. Seek
professional assistance for any repairs or issues.

LESSO GROUP
STOCK CODE: 2128.HK
MPPT Solar Charge Controller User Manual
LET-XB2-HJ Series
*1. The pictures are for reference only, and the actual product shall prevail. *2. Information is subject to update without prior notice.

LET-XB2-HJ Series User Manual
Contents
Important Safety Instructions …………………………………………………………………………………….. 2 Disclaimers ………………………………………………………………………………………………………………. 3 1. General Information………………………………………………………………………………………………. 4
1.1 Overview ………………………………………………………………………………………………………..4 1.2 Appearance ……………………………………………………………………………………………………6 1.3 Naming rules ………………………………………………………………………………………………..11 1.4 System wiring diagram ………………………………………………………………………………….11 2. Installation ……………………………………………………………………………………………………………13 2.1 Attention ……………………………………………………………………………………………………… 13 2.2 Requirements for the PV array ……………………………………………………………………… 14 2.3 Cable specifications …………………………………………………………………………………….. 15 2.4 Mounting the controller …………………………………………………………………………………17 2.5 Wiring the controller …………………………………………………………………………………….. 18 2.6 Powering on the controller …………………………………………………………………………….24 3. Interface ……………………………………………………………………………………………………………… 25 3.1 Indicator ……………………………………………………………………………………………………… 25 3.2 Buttons ……………………………………………………………………………………………………….. 26 3.3 LCD ……………………………………………………………………………………………………………..27 3.4 Browsing real-time data ……………………………………………………………………………….. 28 5.3 Parameters setting ………………………………………………………………………………………. 30 3.6 Load operation mode ……………………………………………………………………………………47 4. Others ………………………………………………………………………………………………………………… 50 4.1 Protections ………………………………………………………………………………………………….. 50 4.2 Troubleshooting ……………………………………………………………………………………………52 4.3 Maintenance ……………………………………………………………………………………………….. 56 5. Technical Specifications ……………………………………………………………………………………….57 6. Appendices ………………………………………………………………………………………………………… 68 6.1 Appendix I Dimensions ………………………………………………………………………………… 68 6.2 Appendix II Abbreviation Index …………………………………………………………………….. 73

Guangdong Lesso Energy Storage Technology Co., Ltd.

1

LET-XB2-HJ Series User Manual
Important Safety Instructions
Please keep this manual for future reference. This manual contains safety, installation and operation instructions for the LET-HxRx-HJ/LET-HxBx-HJ series solar charge controller (hereinafter referred to as “controller”). Read all the instructions and warnings carefully in the manual before installation. No user-serviceable components inside the controller, do not attempt to disassemble or repair the
controller. Install the controller indoors to avoid component exposure and water ingress. Install the controller in a well-ventilated place, the heat sink temperature will be very high during
operation. Do not install the controller in the humid, salt spray, corrosive, greasy, flammable, explosive, dust
accumulative or other harsh environments. It is recommended to install the proper fast-acting fuses/breakers externally. Disconnect PV array connections and the battery fast-acting fuse/breakers before controller
installation and adjustment. Check whether the wiring is tight to avoid the danger caused by heat accumulation due to loose
connection. The entire system should be installed and operated by professional personnel! Symbols explanation To ensure the user’s personal and property safety while using this product, relevant information is provided the manual and highlighted with the following symbols. Please read the relevant texts carefully when you encounter the following symbols in the manual.
DANGER Indicates a high-level hazard that, if not avoided, will result in serious injury or death.
WARNING Indicates a medium-level hazard that, if not avoided, could result in death or serious injury.
CAUTION Indicates a low-level hazard that, if not avoided, could result in minor or moderate injury.

Guangdong Lesso Energy Storage Technology Co., Ltd.

2

LET-XB2-HJ Series User Manual

NOTICE
Indicates an important reminder during the operation which, if ignored, may result in an equipment error alarm.

Tip

Indicates recommendation for reference.

Read through the user manual before any operations.

Disclaimers
The warranty does not apply to the following conditions:
Damage caused by improper use or inappropriate environments (It is strictly forbidden to install the controller in the humid, salt spray, corrosive, greasy, flammable, explosive, dust accumulative or other harsh environments).
The actual current/voltage/power exceeds the limit value of the controller.
Damage caused by operating temperature exceeding the rated temperature range.
Electric arc, fire, explosion and other accidents caused by failure to follow controller labels or manual instructions.
Unauthorized disassembly and maintenance of the controller.
Damage caused by force majeure such as lightning strikes, rainstorms, mountain torrents and utility failures.
Damage occurred during transportation or loading/unloading the controller.

Guangdong Lesso Energy Storage Technology Co., Ltd.

3

LET-XB2-HJ Series User Manual

1. General Information
1.1 Overview
LET-HxRx-HJ/LET-HxBx-HJ series incorporates a new design concept, with solar charge controller as the main body and the built in Bluetooth module (only supported by LET-HxBx-HJ series), users can read and set parameters by App on the phone.
With a brand new generation of MPPT control algorithm, it significantly improves the tracking and response speed of maximum power point. Minimizing the loss rate and time of the maximum power point guarantees the maximum power point tracking efficiency, response speed and DC/DC conversion efficiency in high and low power bands. It can track the maximum power point of the PV arrays in various sunlight conditions and capture the energy from the solar panels.
With independent voltage stabilization, the battery terminal of the controller can be directly connected to the load when there is no battery. It is compatible with various lithium batteries more friendly and comprehensively, and there is no need to worry about the unstable load power supply voltage due to the internal protection of the lithium battery cutting off the output. Excellent low-power design that significantly reduces static power consumption and extends system standby time.
With the functions such as the charging current limit, charging power limit and automatic reduction of charging power at high temperature, it can ensure the system stability when it is connected to the excess PV modules and operating at high temperature.
The controller adopts waterproof and dust-proof design with IP32 protection level, up to IP43 with optional white terminal cover. It has short-circuit protection and isolated RS485 communication interface that can be connected with optional WiFi, Bluetooth, TCP, 4G and other modules to achieve remote monitoring. The communication port can be set to enable (with power output and communication) or disable (no power output, no communication) according to actual needs, and the static power consumption can be further reduced when communication is disabled.
Self-adaptive three-stage charging mode can effectively extend the service life of battery and significantly improve the system performance. It also has comprehensive electronic protections for overcharge, over-discharge and PV/battery reverse polarity etc, to ensure the safety, stability and long-lasting operation of the solar system. It supports up to 6 controllers for parallel charging, which is convenient for system capacity expansion and suitable for different monitoring needs. The controller can be widely used for RV, ship, multiple industrial monitoring, small and medium-sized solar power supply systems and other fields.
Features
Low power consumption with static loss less than 50mA
Independent voltage stabilization
Advanced MPPT technology, with maximum tracking efficiency not less than 99.5%
Supporting two PV inputs to improve PV utilization(1)
Conversion efficiency up to 98.5%

Guangdong Lesso Energy Storage Technology Co., Ltd.

4

LET-XB2-HJ Series User Manual
Supporting multiple battery types, including lithium batteries Stable self-activation for lithium batteries Supporting local setting of main control parameters RS485 communication interface, connected with optional WiFi, Bluetooth, TCP, 4G and other
modules for remote monitoring Some models have built-in Bluetooth module(2) to read and modify parameters directly through
APP Dual limits for rated charging power and charging current Automatic power reduction when charging at high temperature Multiple load control modes Comprehensive electronic protections Protection level IP32, up to IP43 with white terminal cover Built-in independent BMS communication port Built-in CAN parallel communication port Real-time data logging, event logging and energy statistics Remote switch control, easy to turn on/off Dry contact output to turn on/off the oil generator All metal die-casting shell Compliant with IEC62109, UL1741, EMC (Class B) and other relevant standards (1) Two PV inputs are only supported by LET-H80HN2R2-HJ, LET-H100LF2R2-HJ,
LET-H100LF2B2-HJ and LET-H100HF2R2-HJ. (2) The built-in Bluetooth module is only supported by LET-HxBx-HJ series.

Guangdong Lesso Energy Storage Technology Co., Ltd.

5

1.2 Appearance

LET-XB2-HJ Series User Manual

Guangdong Lesso Energy Storage Technology Co., Ltd.

6

LET-XB2-HJ Series User Manual

No.

Description

1

Indicator (see Section 3.1 Indicator)

2

LCD (see Section 3.3 LCD)

3

Buttons (see Section 3.2 Buttons)

4

Protective cover hole (M4)

5

PV2 terminals(1)

6

Mounting hole*4

7

Grounding terminal

8

PV1 terminals(1)

9

Battery terminals(1)

No.

Description

10

Load terminals

11

COM: RS485 COM port (RJ45, with isolation design, 5VDC/200mA)(2)

12

RTS/BMS COM interface(3)

CAN-PARA In: Parallel COM input port for

13

multiple controllers (RJ45, with isolation

design)(4)

CAN-PARA Out: Parallel COM output port

14

for multiple controllers (RJ45, with isolation

design)(4)

15

Charge Enable(5)

16

Dry contact port (Oil generator/Utility)(6)

17

Cooling fan(7)

18

White Terminal Cover (Optional)

(1) The controller is of common negative design, where the negative terminals of PV array, battery and load are the same negative grounding terminals.
(2) Connect optional WiFi, Bluetooth, TCP and 4G modules to the RS485 COM port for remote monitoring. The pins of the RS485 COM port (RJ45) are defined as follows:

Pin

Definition

Pin

Definition

1

+5VDC

5

RS485-A

2

+5VDC

6

RS485-A

3

RS485-B

7

GND

4

RS485-B

8

GND

(3) When the system uses lithium batteries with BMS function, connect the BMS-Link module and lithium batteries through the port 12; with the setting of the BMS protocol number, the BMS-Link

Guangdong Lesso Energy Storage Technology Co., Ltd.

7

LET-XB2-HJ Series User Manual

module can convert the BMS protocols of different lithium battery manufacturers into our standard protocols to realize the communication between the controller and lithium batteries BMS of different manufacturers.
When the system has no BMS function, it is required to set the “BPRO (BMS protocol number)” as 32, connect a remote temperature sensor (model: RTS-D47K) through port 12 to detect the battery temperature, sampling distance 20 meters. Note: If the remote temperature sensor is not connected to the controller, the default temperature for battery charging or discharging is 25°C without temperature compensation.
The pin definitions for port 12 are the same as those for the RS485 COM port 11, see note (2) above.

Tip

Please go to LESSO official website to check or download the currently supported BMS manufacturers and the BMS parameters.

(4) The pins of the parallel COM port for multiple controllers are defined as follows:

(5) The “Charge Enable Switch” is the terminal with silkscreen of “Remote ON/OFF”, which can control PV normal charging. It is set as “Enable” by factory default (i.e PV is charging normally), if
the included 2P terminals are removed from the controller, there is PV charging error.

NOTICE
When the”CPE (COM Port Enable)”is set to “ON (Enable)”, the charge enable switch is valid; when it is set to “OFF (Disable)”, the charge enable switch is invalid. For instructions on CPE

Guangdong Lesso Energy Storage Technology Co., Ltd.

8

LET-XB2-HJ Series User Manual
settings, please refer to Subsection 3.5.1 Parameters list. When the charge enable switch is valid and the included 2P terminals are connected to the
controller, the controller is charging the battery; if the 2P terminals are removed from the controller, the controller stops charging the battery; when the charge enable switch is invalid, the controller is charging the battery by default no matter the 2P terminals are connected to or removed from the controller.
(6) The dry contact port (Oil generator/Utility) is as shown in the figure above with the “Relay” printed on it, where “C” is the common terminal, “NC” is the normally closed contact, and “NO” is the normally open contact. Note: To use only”NO”, or both”NC” and “NO” is subject to the actual control demand of the oil generator when adding the oil generator or there is utility charging in the system.
Power supply parameters applicable to the dry contact port (Oil generator/Utility)
Rated value: 5A/30VDC
Maximum value: 0.5A/60VDC
Control voltage of dry contact port (Oil generator/Utility)
Generator/Utility ON Voltage (VON) = Undervoltage Alarm Voltage minus 0.1V
Generator/Utility OFF (VOFF) = Undervoltage Alarm Recovery Voltage
Battery Voltage (VBAT)
Power on the generator/utility
When VBAT < VON, the “NO (Normally Open)” contact is connected, while the “NC (Normally Closed)” contact is disconnected.
Shut down the generator/utility
When VBAT > VOFF, the “NO (Normally Open)” contact is disconnected, while the “NC (Normally Closed)” contact is connected.
Note: The VON and VOFF can be set via the PC software. For the battery voltage control parameters, please refer to Subsection 3.5.2 Battery voltage control parameters.

Guangdong Lesso Energy Storage Technology Co., Ltd.

9

LET-XB2-HJ Series User Manual

Note: It is not mandatory to connect the oil generator or utility, you can connect them according to your actual needs.
(7) Not all the models are equipped with fans, please refer to the actual product. Only LET-H100LF2R2-HJ, LET-H100HF2R2-HJ and LET-H100LF2B2-HJ are equipped with fans.

Guangdong Lesso Energy Storage Technology Co., Ltd.

10

LET-XB2-HJ Series User Manual
1.3 Naming rules
LET – H 75 L N 2 R 1 – HJ
Series code PV ways: 1 indicates 1 way; 2 indicates 2 ways Communication modeR indicates External mode;
B indicates Built-in Bluetooth module Product type1 indicates PWM; 2 indicates MPPT Usage scenarios: N indicates Self-cooling; F indicates interior air-cooling;
H indicates Outdoor heat exchange; A indicates Outdoor air-cooling; C indicates Outdoor air conditioning Input Voltage: H indicates >150V; L indicates 150V; K indicates 60V; T indicates 100V Rated output current: 50A; 60A; 75A; 80A; 100A
Rated output voltage: A indicates 12V; B indicates 24V; C indicates 36V; D indicates 48V; E indicates 60V; F indicates 96V; G indicates 12-24V; H indicates 12-48V
Product series
1.4 System wiring diagram
No battery mode When there is no battery, LET-HxRx-HJ/LET-HxBx-HJ series controller can be connected to the inverter directly. The inverter must be connected to the battery terminals of the controller and meet the following conditions at the same time: 1) When connecting a high-frequency inverter: PV input power > (load output power divided by the
inverter conversion efficiency divided by the controller conversion efficiency). 2) When connecting an industrial frequency inverter: PV input power > (load output power divided
by the inverter conversion efficiency divided by the controller conversion efficiency ) × 2.

Guangdong Lesso Energy Storage Technology Co., Ltd.

11

LET-XB2-HJ Series User Manual
Battery mode In a system with battery connected, if you need to connect an inverter, please connect the inverter directly to the battery pack, don’t connect the inverter to the load terminals of the controller!

NOTICE Ensure that the length of battery connection cable is less than 3 meters.

Guangdong Lesso Energy Storage Technology Co., Ltd.

12

LET-XB2-HJ Series User Manual
Ensure that the length of load connection cable is less than 3 meters. Ensure that the length of communication cable is less than 3 meters. It is recommended that the length of the PV connection cable is less than 3 meters. If the
length of the PV connection cable is less than 3 meters, it meets the requirements of EN/IEC61000-6-3 standard; If the length of the PV connection cable exceeds 3 meters, it may not meet the requirements of the EN/IEC61000-6-3 standard.
2. Installation
2.1 Attention
Be careful when installing the batteries. Wear protective goggles when installing flooded lead-acid batteries, and rinse with clean water in time once in contact with battery acid.
The battery and PV connections must be guarded against with inadvertent contact. Install the solar charge controller in an enclosure or install the optional white terminal cover.
Keep the battery away from any metal objects to prevent battery short circuit.
Acidic gases may be generated when charging the battery, ensure that the environment is well ventilated.
Avoid direct sunlight and rain infiltration for outdoor installation.
Do not install the controller in the humid, salt spray, corrosive, greasy, flammable, explosive, dust accumulative or other harsh environments.
Loose power connections and corroded cables may result in high heat, melting cables insulation, burning surrounding materials, or even causing a fire. Ensure tight connections and secure cables with cable ties to prevent them from swaying while moving the controller.
Charge the lead-acid and lithium-ion batteries that are within the control range of this controller only.
The battery terminals on the controller can be connected to either the same battery or a group of batteries. The following instructions in the manual are for use with a single battery, but they are also applicable to a system with a group of batteries.
Select the system connection cables according to the current density of no greater than 5A/mm2.
The stripped length for wiring should not be too long, and the exposed metal part of the wire should not protrude from the metal part of the terminal block.
Please refer to IEC62109 for the cross-sectional area of the grounding wire, which should not be less than 4mm2.
The torque for tightening the wiring screws should be not less than 1.2 N·m.

Guangdong Lesso Energy Storage Technology Co., Ltd.

13

LET-XB2-HJ Series User Manual

2.2 Requirements for the PV array
Serial connection (string) of PV modules
Due to the different types of PV modules on the market, and as an important part of the PV system, it is essential for the controller to suit various types of PV modules and to maximize the conversion of solar energy into electricity. According to the open-circuit voltage (VOC) and the maximum power point voltage (VMPP) of the MPPT controller, the suitable serial connection for different PV modules can be calculated. The following PV module series connection table is for reference only.
LET-H60/75LN2R1-HJ, LET-H100LF2R2-HJ, LET-H60LN2B1-HJ, LET-H100LF2B2-HJ:

Battery Voltage/ PV Specifications
12V 24V 48V

36-cell Voc < 23V

Max. Best

4

2

6

3

6

5

48-cell Voc < 31V

Max. Best

2

2

4

2

4

3

54-cell Voc < 34V

Max. Best

2

2

4

2

4

3

60-cell Voc < 38V

Max. Best

2

2

3

2

3

3

Battery Voltage/ PV Specifications
12V 24V 48V

72-cell Voc < 46V

Max.

Best

2

1

3

2

3

2

96-cell Voc < 62V

Max.

Best

1

1

2

1

2

2

Thin-film module Voc > 80V
1 1 1

Note: The above parameters are calculated under the STC (Standard Test Condition)–temperature at 25, air mass 1.5, irradiance 1,000W/m2.
LET-H50/60HN2R1-HJ, LET-H75HN2R1-HJ, LET-H80HN2R2-HJ, LET-H100HF2R2-HJ:

Battery Voltage/ PV Specifications
12V 24V 48V

36-cell Voc < 23V

Max.

Best

4

2

6

3

8

5

48-cell Voc < 31V

Max. Best

3

2

4

2

5

4

54-cell Voc < 34V

Max. Best

2

2

4

2

5

3

60-cell Voc < 38V

Max. Best

2

2

3

2

4

3

Guangdong Lesso Energy Storage Technology Co., Ltd.

14

LET-XB2-HJ Series User Manual

Battery Voltage/ PV Specifications
12V 24V 48V

72-cell Voc < 46V

Max.

Best

2

1

3

2

4

3

96-cell Voc < 62V

Max.

Best

1

1

2

1

2

2

Thin-film module Voc > 80V
1 1 2

Note: The above parameters are calculated under the STC (Standard Test Condition)–temperature at 25, air mass 1.5, irradiance 1,000W/m2.

2.3 Cable specifications
The wiring and installation methods must conform to the national and local electrical code requirements.
Recommended PV array cable size
Since the PV array output current varies according to the PV module’s type, connection method and sunlight angle, the minimum PV cable specifications can be calculated by the PV Isc (short circuit current). For details, please refer to the short-circuit current value in the PV module specifications sheet (the short-circuit current remains unchanged when PV modules are connected in series; when connected in parallel, the short-circuit current is the sum of the short-circuit currents of the parallel modules). The PV array’s ISC must not exceed the controller’s maximum PV input current. For controller’s maximum PV input current and maximum PV cable specifications, please refer to the table below.

Model
LET-H50HN2R1-HJ
LET-H60LN2R1-HJ, LET-H60HN2R1-HJ LET-H60LN2B1-HJ
LET-H75LN2R1-HJ, LET-H75HN2R1-HJ LET-H80HN2R2-HJ
LET-H100LF2R2-HJ LET-H100HF2R2-HJ LET-H100LF2B2-HJ

Maximum Input Current 50A

Maximum Cable Specifications 16mm2/6AWG

60A

16mm2/6AWG

75A 40A*2
50A*2

25mm2/4AWG 16mm2/6AWG
16mm2/6AWG

Guangdong Lesso Energy Storage Technology Co., Ltd.

15

LET-XB2-HJ Series User Manual

NOTICE
When the PV modules connect in series at the lowest temperature, the total voltage must not exceed the controller’s maximum PV open circuit voltage 150V(LET-H**LN2R1-HJ, LET-H60LN2B1-HJ, LET-H100LF2R2-HJ, LET-H100LF2B2-HJ)/200V(LET-H**HN2R1/2-HJ, LET-H100HF2R2-HJ).
When the PV modules connect in series at 25, the total voltage must not exceed the controller’s maximum PV open circuit voltage 138V (LET-H**LN2R1-HJ, LET-H60LN2B1-HJ, LET-H100LF2R2-HJ, LET-H100LF2B2-HJ)/180V (LET-H**HN2R1/2-HJ, LET-H100HF2R2-HJ).

Recommended Battery cable size
Battery cable specifications should be selected according rated current, please refer to the table below for wiring specifications.

Model
LET-H50HN2R1-HJ LET-H60LN2R1-HJ, LET-H60HN2R1-HJ LET-H60LN2B1-HJ
LET-H75LN2R1-HJ, LET-H75HN2R1-HJ
LET-H80HN2R2-HJ LET-H100LF2R2-HJ LET-H100HF2R2-HJ LET-H100LF2B2-HJ

Rated Charging Current 50A
60A

Battery Cable Specifications 16mm2/6AWG
16mm2/6AWG

75A 80A
100A

25mm2/4AWG 25mm2/4AWG
35mm2/2AWG

NOTICE

The cable specification is only for reference. If there is a long distance between the PV array and the controller or between the controller and the battery, thicker cables can be used to reduce the voltage drop and improve system performance.
For the battery, the recommended cable specification is selected according to the conditions that its terminals are not connected to any additional inverter.

Load Wiring Specifications

Model LET-H50HN2R1-HJ

Rated Charging Current 50A

Battery Cable Specifications 16mm2/6AWG

Guangdong Lesso Energy Storage Technology Co., Ltd.

16

LET-XB2-HJ Series User Manual

LET-H60LN2R1-HJ, LET-H60HN2R1-HJ LET-H60LN2B1-HJ
LET-H75LN2R1-HJ, LET-H75HN2R1-HJ
LET-H80HN2R2-HJ
LET-H100LF2R2-HJ LET-H100HF2R2-HJ LET-H100LF2B2-HJ

60A
75A 80A 100A

16mm2/6AWG
25mm2/4AWG 25mm2/4AWG 35mm2/2AWG

2.4 Mounting the controller

DANGER
Risk of explosion! Never install the controller in the enclosed space with flooded batteries! Do not install it in a confined area where battery gas can accumulate either.
Electric shock hazard! The PV array may generate a very high open circuit voltage. Disconnect the circuit breaker or fast-acting fuse first and be careful when wiring.

NOTICE
When installing the controller, ensure that there is enough air flow through the controller’s heat sink, and leave at least 150mm of clearance above and below the controller to guarantee natural convection for heat dissipation. If the controller is mounted in a closed cabinet, ensure that heat can be dissipated through the cabinet.
Step 1: Determine the installation position and heat-dissipation space
When installing the controller, ensure that there is enough air flow through the controller’s heat sink, and leave at least 150mm of clearance above and below the controller to guarantee natural convection for heat dissipation.

Guangdong Lesso Energy Storage Technology Co., Ltd.

17

Installation diagram (IP43)

LET-XB2-HJ Series User Manual Installation diagram (IP32)

Step 2: Remove the terminal cover with a screwdriver before wiring.
2.5 Wiring the controller
Connect the controller in the sequence of “Ground > Battery > Load > PV array > Communication modules”, and disconnect the controller wiring in the reverse order of the following diagram. The following wiring diagram is illustrated with the appearance of “LET-H100HF2R2-HJ”. Please refer to the actual terminals position for correct wiring of other models.

Guangdong Lesso Energy Storage Technology Co., Ltd.

18

LET-XB2-HJ Series User Manual

In addition to supporting stand-alone applications, the LET-HxRx-HJ and LET-HxBx-HJ series series also support the parallel operation of multiple controllers of the same model (up to 6 units). The wiring diagram of multiple controllers is as follows. For instructions on parallel wiring of multiple controllers, please refer to the controller parallel operation manual.
2.5.1 Grounding
LET-HxRx-HJ and LET-HxBx-HJ series are common-negative controllers. Negative terminals of the PV array, battery and load can be grounded simultaneously, or any negative terminal is grounded.

Guangdong Lesso Energy Storage Technology Co., Ltd.

19

LET-XB2-HJ Series User Manual

NOTICE
According to the actual application, the negative terminals of the PV array, battery and load may not be grounded. However, the grounding terminal on the shell must be grounded to effectively shield the external electromagnetic interference and to avoid the electric shock to the human body caused by the live shell.
For common-negative systems, such as the RV system, it is recommended to use a common-negative controller. If a common-positive controller is used and the positive electrode is grounded in the common-negative system, the controller may be damaged.
2.5.2 Connecting the battery
NOTICE
The protection is triggered if there is only battery connection reversed, but don’t reverse the battery connection if the PV is connected correctly, which may damage the controller.
Do not connect the circuit breaker or fast-acting fuse when wiring and ensure that the leads of “+” and “-” poles are connected correctly.
A fast-acting fuse whose current is 1.25 to 2 times the controller’s rated current must be installed on the battery side with a distance from the battery no longer than 150mm.
Please connect the inverter directly to the battery when connecting inverter in the system.

Guangdong Lesso Energy Storage Technology Co., Ltd.

20

LET-XB2-HJ Series User Manual

2.5.3 Connecting the DC/AC loads
DC loads can be directly connected to the load terminals of the controller, while AC loads need to be connected through a DC/AC inverter.
Note: DC load surge current should be less than the product rated value. DC/AC inverter must be connected directly to the battery.

2.5.4 Connecting the PV modules
DANGER Electric shock hazard! The PV array can generate very high voltage, disconnect the circuit

Guangdong Lesso Energy Storage Technology Co., Ltd.

21

LET-XB2-HJ Series User Manual
breaker before wiring, and ensure that the leads of “+” and “-” poles are connected correctly.
NOTICE If controller is used in an area with frequent lightning strikes, an external surge arrester must be installed at the PV input and utility input terminals.

2.5.5 Connecting the optional accessories
Connecting the BMS-Link module
When the system uses lithium batteries with BMS function, connect the BMS-Link module and lithium batteries through the port 12; with the setting of the BMS protocol number, the BMS-Link module can convert the BMS protocols of different lithium battery manufacturers into our standard protocols to realize the communication between the controller and lithium batteries BMS of different manufacturers.

Guangdong Lesso Energy Storage Technology Co., Ltd.

22

LET-XB2-HJ Series User Manual
Connecting the remote temperature sensor (model: RTS-D47K) When the system has no BMS function, attach RTS-D47K close to the battery to detect the battery temperature in real time, and the temperature data will be transmitted to the controller via RS485 communication to improve system safety. Note: It is required to set the BMS protocol number as 32 when connecting the remote temperature sensor to BMS port.
Rem ote tem perature sensor Fixed by high tem perature double coated tap Note: If the remote temperature sensor is not connected to the controller, the default temperature for battery charging or discharging is 25°C without temperature compensation. Connecting the communication module Connect the communication modules such as WiFi, Bluetooth, TCP or 4G modules to the RS485 COM port. You can remotely monitor the controller or modify its related parameters on the APP by phone. For specific setting methods, please refer to the user manuals of communication modules such as Cloud APP, WiFi, Bluetooth, TCP and 4G (Note: 4G module needs to be powered separately).

Guangdong Lesso Energy Storage Technology Co., Ltd.

23

LET-XB2-HJ Series User Manual
W iFi,B luetooth TC P or4G m odules

Note: LET-HxBx-HJ series has built-in Bluetooth module, no external Bluetooth module is required. For specific supported communication module models, please refer to the accessories list.
2.6 Powering on the controller
Connect the battery’s fast-acting fuse to power on the controller. After the LCD normally displays and ensure the charge enable terminals are connected to the controller, connect the PV array’s circuit breaker. The charging indicator is flashing slowly during PV charging.

Tip

If the controller does not work properly or the fault indicator indicates after the controller is powered on, refer to Section 4.2 Troubleshooting.

Guangdong Lesso Energy Storage Technology Co., Ltd.

24

3. Interface

LET-XB2-HJ Series User Manual

Note: The LCD can be viewed clearly when the angle between the end-user’s horizontal sight and the LCD is within 90°. If the angle exceeds 90°, the information on the LCD cannot be viewed clearly.
3.1 Indicator

Indicator PV
BATT

Color Green

Status Solid ON

Green Green

Solid OFF Slowly flashing (1Hz)

Green Fast flashing (4Hz)

Green Solid ON Green Slowly flashing (1Hz) Green Fast flashing (4Hz) Orange Solid ON

Description
PV voltage is higher than turn-off voltage, but no charging.
1. No sunlight; 2. Connection error; 3. PV low voltage
Charging normally
PV input overvoltage, PV mode error, PV/battery input reverse connection, PV relay connection error, PV power too low
Battery is normal.
Battery fully charged, SOC discharging protection, SOC low battery alarm
Battery overvoltage, cell overvoltage
Battery Undervoltage (including battery pack under voltage), cell under voltage

Guangdong Lesso Energy Storage Technology Co., Ltd.

25

LET-XB2-HJ Series User Manual

Red

Solid ON

Battery over discharging

Battery over temperature, battery low

Red

Slowly flashing (1Hz)

temperature, cell over temperature, cell low temperature, BMS charging

protection, BMS discharging protection

Red

Fast flashing (4Hz)

BMS other faults, BMS sensor fault, lithium battery rated voltage identification error alarm

LOAD

Yellow Yellow

Solid ON OFF

Load on Load off, load short circuit, load overload

PV (fast flashing green) & BATT (fast flashing orange)

Equipment over temperature, DSP communication failure

3.2 Buttons
Buttons

Operation Press the button
(< 50ms) Press and hold the button
( > 2.5s)
Press the button (< 50ms)
Press and hold the button (> 2.5s)

Description
Exit the current interface.
Turn on/off the load.
Browse the interface: Up/Down Set the browsing interface: Up/Down Parameters setting interface: Increase or decrease the parameter value as per step size. Browse the interface: invalid. Set the browsing interface: invalid. Parameters setting interface: Increase or decrease the parameter value quickly as per step size.

Press the button (< 50ms)

Confirm the setting parameters.

Press and hold the button (> 2.5s)

Switch the real-time interface to setting browsing interface.

Guangdong Lesso Energy Storage Technology Co., Ltd.

26

3.3 LCD

LET-XB2-HJ Series User Manual
Switch the setting browsing interface to parameter settings interface. Confirm the setting parameters.

Name PV array
Battery Load

Icon Day Night

Status

Not charging

PV1/PV2 BAT

Charging Note: “B, E, F” refer to bulk charging, equalization charging and float charging respectively.
Displays the input voltage, input current, input power and input energy of PV1 and PV2, see Subsection 3.4.1 PV.
Displays battery voltage, battery total current (charging current), battery charging/discharging power (determined by current), battery SOC, and battery temperature, see Subsection 3.4.2 Battery.
Load ON

Guangdong Lesso Energy Storage Technology Co., Ltd.

27

LET-XB2-HJ Series User Manual

Load OFF

LOAD

Displays load output current, load output power, load output energy, load manual operating mode, sunset load ON mode, see Subsection 3.4.3 Load.

3.4 Browsing real-time data

3.4.1 PV

After the controller is powered on and works normally, press

on the LCD initial interface to

display the following PV real-time data interfaces in sequence, you can view PV1 input voltage, PV1 input current, PV1 input power, PV1 input energy, PV2 input voltage, PV2 input current, PV2 input power, and PV2 input energy. Note: Model with single PV input displays PV1 only.

3.4.2 Battery

Click

on the real-time data interface of “PV2 input energy” to display the following battery

real-time data interfaces in sequence, you can view the battery voltage, battery total current (charging current), battery charging/discharging power (determined by current), battery SOC, and battery temperature.

Guangdong Lesso Energy Storage Technology Co., Ltd.

28

LET-XB2-HJ Series User Manual

3.4.3 Load

Press

on the real-time data interface of “Battery temperature” to display the following

load real-time data interfaces in sequence, you can view the load output current, load output power, load output energy, load operating mode (manual), and load operating mode (sunset load ON).

Guangdong Lesso Energy Storage Technology Co., Ltd.

29

LET-XB2-HJ Series User Manual

5.3 Parameters setting

Operation steps:

Step 1: In PV/battery/load real-time data browsing interface, press and hold the

button to enter

the parameter setting interface. Then, press the

button to select the parameter to

be set. Next, press and hold the

button to enter the setting interface of the parameter

(the parameter value is blinking). Modify the parameter value by pressing the

button. And Press the

button to confirm the parameter value.

Step 2: Press

button to exit the parameters setting interface and switch to the real-time data

browsing interface.

3.5.1 Parameters list
The default values and setting range of the controller parameters on the LCD are shown in the following table, except for some read-only parameters, other parameters can be directly modified by the LCD:

Parameters
BT (Battery Type)

Default AGM

User define
48V system: AGM, GEL, FLD, LFP15S, LFP16S, LNCM13S, LNCM14S, USER
24V system: AGM, GEL, FLD, LFP8S, LNCM6S, LNCM7S, USER

Guangdong Lesso Energy Storage Technology Co., Ltd.

30

LET-XB2-HJ Series User Manual

BC (Battery Capacity)
TCC (Temperature Compensation Coefficient) RVL (Rated Voltage Level)
OVD (Overvoltage Disconnect Voltage)
CVL (Charging Voltage Limit Voltage)

100Ah
3
0
16.0V (12V system)
32.0V (24V system)
64.0V (48V system)
15.0V (12V system)
30.0V (24V system)
60.0V (48V system)

12V system: AGM, GEL, FLD, LFP4S, LNCM3S, USER
User define: 1­4,000Ah Products of 200Ah and below, small step size 1Ah, large step size: 10Ah Products above 200Ah, small step size 5Ah, large step size: 50Ah Note: To accurately display the battery capacity, you need to set this parameter according to the actual battery capacity.
0 for lithium battery 0­9 for non-lithium battery, indicating 0 to -9, step size: 1
User define: 0 (auto-recognition), 12V, 24V, 36V, 48V Note: After modifying the system rated voltage level, restart the controller for the modification to take effect.
User define: 9.0­17.0V, small step size: 0.1V, large step size: 1V
User define: 18.0­34.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­68.0V, small step size: 0.1V, large step size: 1V
User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V
User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V

OVR (Overvoltage

15.0V (12V system)

User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V

Guangdong Lesso Energy Storage Technology Co., Ltd.

31

LET-XB2-HJ Series User Manual

Recovery Voltage)

30.0V (24V system)

User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V

ECV (Equalization Charging Voltage)
BCV (Bulk Charging Voltage)
FCV (Float Charging Voltage)
BVR (Bulk Voltage Recovery Voltage)
LVR (Low Voltage

60.0V (48V system)
14.6V (12V system)
29.2V (24V system)
58.4V (48V system)
14.4V (12V system)
28.8V (24V system)
57.6V (48V system)
13.8V (12V system)
27.6V (24V system)
55.2V (48V system)
13.2V (12V system)
26.4V (24V system)
52.8V (48V system)
12.6V

User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V
User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V
User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V
User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V
User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V
User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V
User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V
User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V
User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V
User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V

Guangdong Lesso Energy Storage Technology Co., Ltd.

32

LET-XB2-HJ Series User Manual

Recovery Voltage)
UVAR (Undervoltage Alarm Recovery Voltage)
UVA (Undervoltage Alarm Voltage)
LVD (Low Voltage Disconnect Voltage)
DVL (Discharging Voltage Limit Voltage)

(12V system)
25.2V (24V system)
50.4V (48V system)
12.2V (12V system)
24.4V (24V system)
48.8V (48V system)
12.0V (12V system)
24.0V (24V system)

User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V
User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V
User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V
User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V
User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V

48.0V (48V system)

User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V

11.1V (12V system)

User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V

22.2V (24V system)

User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V

44.4V (48V system)

User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V

10.6V (12V system)
21.2V (24V system)
42.4V (48V system)

User define: 9.0­15.5V, small step size: 0.1V, large step size: 1V
User define: 18.0­31.0V, small step size: 0.1V, large step size: 1V
User define: 36.0­62.0V, small step size: 0.1V, large step size: 1V

Guangdong Lesso Energy Storage Technology Co., Ltd.

33

LET-XB2-HJ Series User Manual

ECT (Equalize Charging Time)
BCT (Bulk Charging Time)
CDM (Charging/Discha rging Mode)
FCPS (Full Charge Protection SOC)
FCPR (Full Charge Protection Recovery SOC)
DPRS (Discharging Protection Recovery SOC)
LBAR (Low Battery Alarm Recovery SOC)
LBAS (Low Battery Alarm SOC)
DPS (Discharging Protection SOC)
LBP (Lithium Battery Protection)

120M 120M UO99% 95% 10% 10%
8% 5% OFF

User define: 0­180 minutes, small step size: 1 minute, large step size: 10 minutes
User define: 0­180 minutes, small step size: 1 minute, large step size: 10 minutes
User define: UO-(voltage compensation), SOC
User define: 80%­100%, small step size: 1%, large step size: 5% Note: This parameter value must be greater than or equal to FCPR (Full Charge Protection Recovery SOC) plus 2%.
User define: 80%­99%, small step size: 1%, large step size: 5%
User define: 1%­50%, small step size: 1%, large step size: 5%
User define: 1%­50%, small step size: 1%, large step size: 5%
User define: 1%­20%, small step size: 1%, large step size: 5%
User define: 1%­20%, small step size: 1%, large step size: 5%
User define: OFF, ON OFF: Disable lithium battery protection ON: Enable lithium battery protection

Guangdong Lesso Energy Storage Technology Co., Ltd.

34

LET-XB2-HJ Series User Manual

LTCL (Low Temperature Charging Limit)
LTDL (Low Temperature Discharging Limit) MEC (Manual Equalize Charging)
MCC (Battery Max Charging Current) Note: This parameter cannot be modified when BMS is connected, the charging is controlled by BMS.
LCM (Load Control Mode)

-5 -20 OFF 50A 60A 75A 80A 100A
0

User define: -25 to 10, small step size: 1, large step size: 10 Note: This parameter goes into effect when “LBP (Lithium Battery Protection)” is set as “ON”.
User define: -25 to 10, small step size: 1, large step size: 10 Note: This parameter goes into effect when “LBP (Lithium Battery Protection) is set as “ON”.
User define: OFF, ON Set to “ON” to enable the controller and start equalization charging.
LET-H50HN2R1-HJ: User define: 1­50A, small step size: 1A, large step size: 10A
LET-H60LN2R1-HJ, LET-H60HN2R1-HJ, LET-H60LN2B1HJ: User define: 1­60A, small step size: 1A, large step size: 10A
LET-H75LN2R1-HJ, LET-H75HN2R1-HJ: User define: 1­75A, small step size: 1A, large step size: 10A
LET-H80HN2R2-HJ: User define: 1­80A, small step size: 1A, large step size: 10A
LET-H100LF2R2-HJ, LET-H100HF2R2-HJ, LET-H100LF2B2-HJ: User define: 1­100A, small step size: 1A, large step size: 10A
User define: 0, 1, 2, 3, 6, 7 0: Manual Mode (Default) 1: Sunset Load ON Mode 2: Sunset Load ON + Timer Mode 3: Timer Mode

Guangdong Lesso Energy Storage Technology Co., Ltd.

35

MMDS (Manual Mode Default Switch)
TOND (Turn-On Delay)
TOFD (Turn-Off Delay)
TCP (Timing Control Period)
WDH1 (Working Duration 1–Hour)
WDM1 (Working Duration 1–Minute) WDH2 (Working Duration 2–Hour)

LET-XB2-HJ Series User Manual

6: Always ON Mode 7: Sunrise Load ON Mode

Default load switch in manual mode

1

User define: 0 (Load OFF), 1 (Load ON)

Note: After setting the parameter, restart the controller for

the setting to take effect.

If the PV panel voltage is greater than the nighttime

threshold voltage, the duration of this voltage exceed

10M

s the confirmation time of PV signal ON (nighttime) , it is considered to be nighttime.

User define: 0­99 minutes, small step size: 1 minute, large step size: 10 minutes.

If the PV panel voltage is greater than the daytime

threshold voltage, the duration of this voltage exceeds the

10M

confirmation time of PV signal OFF (daytime) , it is considered to be daytime.

User define: 0­99 minutes, small step size: 1 minute, large step size: 10 minutes.

Set the selected period for load.

User define: 0, 1

0

0 indicates using 1 period, while 1 indicates using 2

periods.

Note: It is used for load in “Timer Mode”.

The first duration of load output, in hours.

User define: 0­24 hours, step size: 1 hour.

6h

Note: It is used for load in “Sunset Load ON + Timer

Mode”.

The first duration of load output, in minutes.

0M

User define: 0­59 minutes, small step size: 1 minute, large step size: 10 minutes.

Note: It is for load in “Sunset Load ON + Timer Mode”.

The second duration of load output, in hours.

6h

User define: 0­24 hours, step size: 1 hour.

Note: It is for load in “Sunset Load ON + Timer Mode”.

Guangdong Lesso Energy Storage Technology Co., Ltd.

36

LET-XB2-HJ Series User Manual

WDM2 (Working Duration 2–Minute)
NTH (Night Time–Hour)
NTM (Night Time–Minute) BPRO (BMS Protocol)
UBS (Use BMS Settings)
SBM (Simulate BMS Mode)
PCM (PV Connection Mode)

The second duration of load output, in minutes.

User define: 0­59 minutes, small step size: 1 minute, large

0M

step size: 10 minutes.

Note: It is used for load in “Sunset Load ON + Timer Mode”.

The duration of the entire night, which can be autom

atically detected by devices with sunlight collection.

12h

User define: 3­12 hours, step size: 1 hour.

Note: It is for load in “Sunset Load ON + Timer Mode”.

User define: 0­59 minutes, small step size: 1 minute, large

0M

step size: 10 minutes.

Note: It is used for load in “Sunset Load ON + Timer

Mode”.

32

User define: 1­230, small step size: 1, large step size: 10

User define: OFF, ON

When set to “ON”, after the BMS is enabled and the

controller reads valid BMS parameters, it performs current

limit control on charging according to the read current

OFF

limit values of charging.

Note: If “UBS” is set to “ON”, the battery voltage control parameters cannot be set; it is required to set “UBS” to “OFF” and restart the controller to set the battery voltage control parameters.

User define: OFF, ON

When set to “ON”, it simulates the BMS end current

OFF

limiting.

Note: It is used for lithium batteries without BMS com

munication or BMS without terminal current limiting

function.

User define: INDE (independent), CEN (Centralize)

When two PV arrays are independently input, the value

shall be set to “INDE”. When two PV arrays are connected

CEN

in parallel as a single input to the controller (the PV

terminals need to be paralleled externally), the value shall

be set to “CEN”.

Note: When two PV arrays are connected and “PCM (PV

Guangdong Lesso Energy Storage Technology Co., Ltd.

37

ADDR (Address)
BAUD (Baudrate)
TU (Temperature Unit)
SBT (Screen Backlight Time)
SCT (Screen Cycle Time)
DRP (Data Record Period)
PRCP (PV Restart Charging Period)

1 1,152
100S
2S 10M 10M

LET-XB2-HJ Series User Manual
Connection Mode)” is set to “CEN”, if the PV charging current is less than 9A, there is only one PV array charging the battery; when the PV charging current is greater than 9A, both PV arrays are charging the battery simultaneously. Product with one PV input is “IDNE” by default (this parameter setting is invalid).
User define: 1­200, small step size: 1, large step size: 10
User define: 1,152, 96, 24, step size: 24 Note: After setting the parameter, restart the controller for the setting to take effect.
User define: C, F
If there is no operation on the LCD for more than the time set in “SBT”, the LCD will turn off. User define: 0­100S, small step size: 1S, large step size: 10S 0 second indicates solid OFF, while 100 seconds indicate solid ON.
The switching time of the real-time interface is 0S by default, that is, the real-time interface is not automatically switched. User define: 0­100S, small step size: 1S, large step size: 10S
Set the time interval of the historical data (only refers to the voltage, current and other data stored regularly, excluding the historical faults. These historical data can be exported by the Solar Guardian PC software or Website.) User define: 10­120 minutes, small step size: 1 minute, large step size: 10 minutes
The delayed charging time when PV is underpowered due to weather conditions. User define: 0­60 minutes, small step size: 1 minute, large step size: 10 minutes. When set to “0”, there is no delay for PV restart charging period.

Guangdong Lesso Energy Storage Technology Co., Ltd.

38

LET-XB2-HJ Series User Manual

CPE (Com Port Enable)
ROT (Remote ON/OFF Terminal)
CAE (Clear Accumulated Energy)
PMCC (Parallel Battery Max Charging Current)
RFS (Restore Factory Settings) AFV (ARM Firmware

ON
OFF OFF 1,200A OFF
—

Note: Small step size refers to the parameter value that is increased or decreased by clicking the button once, while large step size refers to the parameter value that is increased or decreased by pressing and holding the button once. This concept that appears later will not be repeated.
User define: OFF, ON
When set to “ON”, the communication port is enabled and communication is normal.
When set to “OFF”, the external communication is turned off when there is no PV input or charging, otherwise the communication is turned on.
User define: OFF, ON
When set to “ON”, the remote ON/OFF terminal is enabled and can start/stop the controller charging. When the included terminal is connected, the controller is charging; when the included terminal is removed, the controller stops charging.
When set to “OFF”, the remote ON/OFF terminal is disabled and the controller is charging by default no matter the terminal is removed from or connected to the controller.
User define: OFF, ON
When set to “ON”, the accumulated energy is cleared once.
Limit the total current for parallel charging. If the setting value of this parameter exceeds the maximum charging current of an individual controller times the quantity of parallel controllers, the parameter is invalid and the system will limit the charging according to the maximum charging current of the individual controller.
User define: 100­1,200A, small step size: 10A, large step size: 100A
User define: OFF, ON
When set to “ON”, the factory settings are restored once.
Read-only.
Note: Please refer to the actual display for the specific

Guangdong Lesso Energy Storage Technology Co., Ltd.

39

LET-XB2-HJ Series User Manual

Version)

version.

DFV
(DSP Firmware Version)

Read-only.

—

Note: Please refer to the actual display for the specific

version.

3.5.2 Battery voltage control parameters
1) Lead-acid battery parameters
The following table shows the voltage control parameters of 12V system (12V battery), voltage control parameters and user-define range of 24V system (24V battery) and 48V system (48V battery) are equal to the parameter values of 12V system times 2 and 4 respectively.

Battery Type
Voltage Control Parameters Overvoltage Disconnect Voltage Charging Voltage Limit Voltage Overvoltage Recovery Voltage Equalization Charging Voltage Bulk Charging Voltage Float Charging Voltage Bulk Recovery Voltage Low Voltage Recovery Voltage Undervoltage Alarm Recovery Voltage Undervoltage Alarm Voltage Low Voltage Disconnect Voltage Discharging Voltage Limit Voltage
Equalization Charging Time
Bulk Charging Time

AGM
16.0V 15.0V 15.0V 14.6V 14.4V 13.8V 13.2V 12.6V
12.2V
12.0V 11.1V 10.6V 120 minutes 120 minutes

GEL
16.0V 15.0V 15.0V
-14.2V 13.8V 13.2V 12.6V
12.2V
12.0V 11.1V 10.6V
—
120 minutes

FLD
16.0V 15.0V 15.0V 14.8V 14.6V 13.8V 13.2V 12.6V
12.2V
12.0V 11.1V 10.6V 120 minutes 120 minutes

User define
9­17V 9­15.5V 9­15.5V 9­15.5V 9­15.5V 9­15.5V 9­15.5V 9­15.5V
9­15.5V
9­15.5V 9­15.5V 9­15.5V 0­180 minutes 10­180 minutes

When the battery type is changed to lithium battery, the lithium battery protection is automatically

Guangdong Lesso Energy Storage Technology Co., Ltd.

40

LET-XB2-HJ Series User Manual

enabled, and the default values of “ECT” and “BCT” are changed to 10 minutes.
When the battery type is changed to “AGM, GEL or FLD”, the lithium battery protection is disabled, and the default values of “ECT” and “BCT” are changed to 120 minutes.
When the battery type is changed to “USER”, the values of lithium battery protection, “ECT” and “BCT” remain the same as the previous battery type.
When the default battery type is selected, the battery voltage control parameters cannot be modified. To change these parameters, select the battery type as “USER”. Follow the logic below to set the battery type as “USER”
A. Overvoltage Disconnect Voltage > Charging Voltage Limit Voltage Equalization Charging Voltage Bulk Charging Voltage Float Charging Voltage > Bulk Recovery Voltage;
B. Overvoltage Disconnect Voltage > Overvoltage Recovery Voltage;
C. Low Voltage Recovery Voltage > Low Voltage Disconnect Voltage Discharging Voltage Limit Voltage;
D. Undervoltage Alarm Recovery Voltage > Undervoltage Alarm Voltage Discharging Voltage Limit Voltage;
E. Bulk Recovery Voltage > Low Voltage Recovery Voltage.
2) Lithium battery parameters

Battery Type
Voltage Control Parameters Overvoltage Disconnect Voltage Charging Voltage Limit Voltage Overvoltage Recovery Voltage Equalization Charging Voltage Bulk Charging Voltage Float Charging Voltage Bulk Recovery Voltage Low Voltage Recovery Voltage Undervoltage Alarm Recovery Voltage Undervoltage Alarm Voltage Low Voltage Disconnect Voltage

LFP4S 14.5V 14.3V 14.3V 14.2V 14.2V 13.3V 13.0V 12.8V 12.2V 12.0V 11.3V

LFP

User Define

LFP8S

9­17V

29.0V

9­15.5V

28.6V

9­15.5V

28.6V

9­15.5V

28.4V

9­15.5V

28.4V

9­15.5V

26.6V

9­15.5V

26.0V

9­15.5V

25.6V

9­15.5V

24.4V

9­15.5V

24.0V

9­15.5V

22.6V

User Define 18­34V 18­31V 18­31V 18­31V 18­31V 18­31V 18­31V 18­31V 18­31V 18­31V 18­31V

Guangdong Lesso Energy Storage Technology Co., Ltd.

41

LET-XB2-HJ Series User Manual

Discharging Voltage Limit Voltage

11.0V

9­15.5V

22.0V

18­31V

Note: The LFP4S voltage is 12V, the LFP8S voltage is 24V.

Battery Type
Voltage Control Parameters Overvoltage Disconnect Voltage Charging Voltage Limit Voltage Overvoltage Recovery Voltage Equalization Charging Voltage Bulk Charging Voltage Float Charging Voltage Bulk Recovery Voltage Low Voltage Recovery Voltage Undervoltage Alarm Recovery Voltage Undervoltage Alarm Voltage Low Voltage Disconnect Voltage Discharging Voltage Limit Voltage

LFP15S 54.7V 53.6V 53.6V 53.3V 53.3V 50.0V 49.7V 48.0V 45.7V 45.0V 42.5V 41.5V

LFP LFP16S 59.2V 58.4V 58.4V 57.12V 57.12V 54.4V 53.28V 52.0V 51.2V 49.6V 46.4V 44.0V

User Define 36­68V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V

Note: The voltage of LFP15S and LFP16S is 48V.

Battery Type

Voltage Control Parameters
Overvoltage Disconnect Voltage
Charging Voltage Limit Voltage
Overvoltage Recovery Voltage
Equalization Charging Voltage

LNCM3S 12.8V 12.6V 12.5V 12.5V

User Define 9­17V
9­15.5V
9­15.5V
9­15.5V

LNCM LNCM6S
25.6V 25.2V 25.0V 25.0V

LNCM7S 29.8V 29.4V 29.1V 29.1V

User Define 18­34V
18­31V
18­31V
18­31V

Guangdong Lesso Energy Storage Technology Co., Ltd.

42

LET-XB2-HJ Series User Manual

Bulk Charging Voltage
Float Charging Voltage
Bulk Recovery Voltage
Low Voltage Recovery Voltage
Undervoltage Alarm Recovery Voltage
Undervoltage Alarm Voltage
Low Voltage Disconnect Voltage
Discharging Voltage Limit Voltage

12.5V 12.2V 12.1V 10.5V
12.2V 10.5V 9.3V
9.3V

9­15.5V 9­15.5V 9­15.5V 9­15.5V
9­15.5V 9­15.5V 9­15.5V
9­15.5V

25.0V 24.4V 24.2V 21.0V
24.4V 21.0V 18.6V
18.6V

29.1V 28.4V 28.2V
24.5V

18­31V 18­31V 18­31V
18­31V

28.4V 24.5V 21.7V

18­31V 18­31V 18­31V

21.7V

18­31V

Note: The LNCM3S voltage is 12V, the voltage of LNCM6S and LNCM7S is 24V.

Battery Type
Voltage Control Parameters Overvoltage Disconnect Voltage Charging Voltage Limit Voltage Overvoltage Recovery Voltage Equalization Charging Voltage Bulk Charging Voltage Float Charging Voltage Bulk Recovery Voltage Low Voltage Recovery Voltage Undervoltage Alarm Recovery Voltage Undervoltage Alarm Voltage Low Voltage Disconnect Voltage Discharging Voltage Limit Voltage

LNCM13S 55.4V 54.6V 54.1V 54.1V 54.1V 52.8V 52.4V 45.5V 52.8V 45.5V 40.3V 40.3V

LNCM LNCM14S
59.7V 58.8V 58.3V 58.3V 58.3V 56.9V 56.4V 49.0V 56.9V 49.0V 43.4V 43.4V

User Define 36­68V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V 36­62V

Note: The voltage of LFP15S and LFP16S is 48V.

Guangdong Lesso Energy Storage Technology Co., Ltd.

43

LET-XB2-HJ Series User Manual

When the battery type is set as “USER”, follow the logic below to set the voltage parameters of the lithium battery.
A. Overvoltage Disconnect Voltage > Over Charging Protection Voltage (Protection Circuit Modules(BMS)) plus 0.2V;
B. Overvoltage Disconnect Voltage > Overvoltage Recovery Voltage = Charging Voltage Limit Voltage Equalization Charging Voltage = Bulk Charging Voltage Float Charging Voltage > Bulk Recovery Voltage;
C. Low Voltage Recovery Voltage > Low Voltage Disconnect Voltage Discharging Voltage Limit Voltage;
D. Undervoltage Alarm Recovery Voltage > Undervoltage Alarm Voltage Discharging Voltage Limit Voltage;
E. Bulk Recovery Voltage > Low Voltage Recovery Voltage;
F. Low Voltage Disconnect Voltage Over Discharging Protection Voltage (BMS) plus 0.2V.
NOTICE
The lithium battery parameters must be set according to its BMS voltage parameters. It is required that the BMS accuracy of the lithium battery installed in the system is less than or
equal to 0.2V, if it is higher than 0.2V, we shall not be liable for any system error.

3.5.3 Control strategy under lithium battery protocol
When the BMS is connected correctly, the BPRO (BMS protocol) is set correctly, and “UBS (Use BMS Settings)” is set to “ON”, the system follows the following control strategies:

No.

Status/Condition

Control strategy

1

Battery forced charge request appears.

Forced charge the battery with the charging current value provided by the BMS.

2

The BMS sends an exit forced charge command.

Exit the battery forced charge mode and resumes normal operating mode.

BMS prohibits discharging

3

(including over temperature, discharge over current, cell

Turn off loads.

under-voltage, etc.)

Read the charging voltage

4

upper limit and the discharging voltage lower

limit from the BMS

Each control voltage is converted according to the table “Conversion Relationship of Each Control Voltage”, and the system is charged according to the converted voltage value, and the LCD meter displays

Guangdong Lesso Energy Storage Technology Co., Ltd.

44

LET-XB2-HJ Series User Manual

the converted voltage value.
Note: If the BMS communication is normal but charging voltage upper limit and the discharging voltage lower limit cannot be read, the system will be charged according to the value set by the customer.

5

Read the charging limit current from the BMS.

Limit the charging current as the read charging current limit value.

6

Turn off charging meter and display BCF.

BMS uploads the battery full charge status (Battery is fully charged).

BMS voltage and current

7

limiting parameters are

taking effect.

The controller limits charging according to the maximum charging current value uploaded by BMS and the meter displays BLC.

For the maximum charging voltage and the minimum discharging voltage of the lithium battery, please refer to its specification sheet.
Conversion Relationship of Each Control Voltage

No.

LCD

Control Voltage

Converted Voltage

1

OVD

Overvoltage Disconnect Voltage

Charging Voltage Upper Limit + 0.3 × Level

2

CLV

Charging Limit Voltage

Charging Voltage Upper Limit (namely, the Battery Pack Overvoltage Alarm Voltage)

3

OVR

Overvoltage Recovery Voltage

Charging Voltage Upper Limit

4

ECV

Equalization Charging Voltage

Charging Voltage Upper Limit – 0.1 × Level

5

BCV

Bulk Charging Voltage

Charging limit voltage – 0.1 × Level

6

FCV

Float Charging Voltage Charging limit voltage – 0.1 × Level

7

BVR

Bulk Recovery Voltage Charging Voltage Upper Limit – 0.8 × Level

8

LVR

Low Voltage Recovery Voltage

Discharging Voltage Lower Limit + 0.7 × Level

9

UVR

Undervoltage Alarm Recovery Voltage

Discharging Voltage Lower Limit + 0.7 × Level

10

UVW

Undervoltage Alarm Voltage

Discharging Voltage Lower Limit + +0.4 × Level

Guangdong Lesso Energy Storage Technology Co., Ltd.

45

LET-XB2-HJ Series User Manual

11

LVD

Low Voltage Disconnect Discharging limit voltage (namely, the battery

Voltage

pack Undervoltage Alarm Voltage)

12

DLV

Discharging Limit Voltage

Discharging limit voltage – 0.7 × Level

3.5.4 Setting parameters remotely
1) Setting the “USER” voltage parameters by PC software
Connect the COM port of the controller to the PC USB port by the USB to RS485 communication cable. Set the “USER” voltage parameters by the PC software.

2) Setting by APP
Connecting the external WiFi module
Connect the WiFi module to the COM port of the controller, set the “USER” voltage parameters on the APP through the WiFi signal. For specific setting methods, please refer to the cloud APP manual.

Connecting the external Bluetooth module
Connect the Bluetooth module to the COM port of the controller, set the “USER” voltage parameters on the APP through the Bluetooth signal. For specific setting methods, please refer to the cloud APP manual.

Guangdong Lesso Energy Storage Technology Co., Ltd.

46

LET-XB2-HJ Series User Manual

The built-in Bluetooth module (supported by LET-HxBx-HJ series only)
Connect the built-in Bluetooth module of the controller through the mobile phone Bluetooth switch. set the “USER” voltage parameters on the APP through the Bluetooth signal. For specific setting methods, please refer to the cloud APP manual.

3.6 Load operation mode

3.6.1 Setting via the LCD screen

In PV/battery/load real-time data browsing interface, press and hold the

button to enter the

parameter setting interface. Press the

button to select the parameter “LCM (load

Control Mode)”. Press and hold the

button to enter the setting interface of the “LCM” (the

parameter value is blinking). Modify the “LCM” value by pressing the

button. Press

the

button to confirm the parameter value.

Press

button to exit the “LCM (Load Control Mode)” setting interface and switch to the

real-time data browsing interface.

Guangdong Lesso Energy Storage Technology Co., Ltd.

47

LET-XB2-HJ Series User Manual

The default value for “LCM (Load Control Mode)” is 0, it can be set as “0 (Manual Mode), 1 (Sunset Load ON Mode), 2 (Sunset Load ON + Timer Mode), 3 (Timer Mode), 6 (Always ON Mode), 7 (Sunrise Load ON Mode)”.
When “LCM (Load Control Mode)” is set as “0 (Manual Mode)”, please refer to parameter settings flowchart above to modify the value of “MMDS (Manual Mode Default Switch)”. When “MMDS” is set as 1 (default value), indicating loads are ON, restart the controller for this parameter setting to take effect after modifying is complete.
When setting “LCM (Load Control Mode)” is complete, return to the load real-time data interface (see Chapter 3.4.3 AC load) to view the codes of load operating modes as follows.

1** 100 101 102 103­113 114 115 116

Timer 1
Sunset Load ON Mode
Load will be on for 1 hour since sunset.
Load will be on for 2 hours since sunset.
Load will be on for 3-13 hours since sunset.
Load will be on for 14 hours since sunset.
Load will be on for 15 hours since sunset.
Test mode

2** 200 201 202 203­213 214 215 200

Timer 2
Default, not configurable
Load will be on for 1 hour before sunrise.
Load will be on for 2 hours before sunrise.
Load will be on for 3-13 hours before sunrise.
Load will be on for 14 hours before sunrise.
Load will be on for 15 hours before sunrise.
Default, not configurable

Guangdong Lesso Energy Storage Technology Co., Ltd.

48

LET-XB2-HJ Series User Manual

117

Manual mode (ON by default)

Always ON mode (The load is

always on after being powered on,

200

Default, not configurable

118

this mode is suitable for the loads

which require 24-hour power

supply.)

Note: When “LCM (Load Control Mode)” is set as 1 (Sunset Load ON Mode Mode), 2 (Sunset Load ON Mode + Timer Mode), 7 (Sunrise Load ON Mode) or 0 (Manual Mode), only Timer 1 can be set. Timer 2 will be disabled and display as “200”.
3.6.2 Setting via the RS485 communication port
1. Load operating modes
Manual mode (ON by default)
Turn ON/OFF of the load by pressing the button manually or remote commands (such as PC software, APP and remote monitoring unit).
Sunset Load ON Mode

Load O N Load O FF
D usk
Sunset Load ON + Timer Mode

N ight tim e

D aw n

Guangdong Lesso Energy Storage Technology Co., Ltd.

49

Sunrise Load ON Mode

LET-XB2-HJ Series User Manual

Timer Mode
Control the load ON/OFF time by setting the real-time clock.
2. Load operating mode settings The load operating modes can be set by PC software, APP and remote monitoring unit, please refer to Subsection 3.5.4 Setting parameters remotely for wiring diagram and setting methods.

4. Others
4.1 Protections
Protections PV current/power-limiting
PV short circuit
PV reverse polarity Night reverse charging

Description
When the actual charging current/power of the PV array exceeds its rated current/power, it will charge the battery as per the rated current/power.
When PV is not charging the battery and is short-circuit, the controller will not be damaged. Note: It is forbidden to short-circuit the PV array during charging. Otherwise, the controller may be damaged.
When the PV array polarity is reversed, the controller will not be damaged and will resume normal operation after correction. Note: If the PV array is reversed and its actual power is 1.5 times the controller’s rated power, the controller will be damaged.
At night, since the battery voltage is greater than the PV module voltage, it can prevent the battery from discharging through the

Guangdong Lesso Energy Storage Technology Co., Ltd.

50

LET-XB2-HJ Series User Manual

PV module.

Battery overvoltage Battery over discharge Battery over temperature
Battery reverse polarity

When the battery voltage is higher than the “OVD (Overvoltage Disconnect Voltage)”, the controller will automatically stop charging the battery to protect the battery from over charging.
When the battery voltage is lower than the “LVD (Low Voltage Disconnect Voltage)”, the over discharge alarm will occur on the LCD.
The controller detects the battery temperature by an external temperature sensor. The battery stops working when its temperature goes higher than 65 and resumes operation when its temperature is below 55.
When the battery polarity is reversed alone, or the PV and battery are reversed at the same time, or the battery is reversed first and the PV is connected correctly later, the controller will not be damaged and will continue to work after the wiring error is corrected.
Note: When PV is connected correctly and the controller is working, then the battery polarity is reversed, the controller will be damaged.

Lithium battery low temperature charging and discharging

When the temperature detected by the optional temperature sensor is lower than “LTCL (Low Temperature Charging Limit)”, the controller stops charging automatically. When the detected temperature is higher than the “LTCL”, the controller resumes charging automatically. (The “LTCL” is 0°C by default and can be set within the range from -40°C to 10°C. For detailed settings of relevant parameters, please refer to Subsection 3.5.1 Parameters list.

Load Over Load

If the load current exceeds 1.02 times the controller’s rated current, the controller will cut off the output after a delay. When overload occurs, after the fifth (delay of 5S, 10S, 15S, 20S, 25S) automatic output recovery fails, reduce the electrical appliances at the load end, restart the controller or let the controller undergo a change from night to day (nighttime duration > 3 hours) to clear this protection.

Guangdong Lesso Energy Storage Technology Co., Ltd.

51

LET-XB2-HJ Series User Manual

Load short-circuit
Controller over temperature
TVS high voltage surge

When a short circuit occurs at the load end ( 4 times the rated load current), the controller will automatically protect and cut off the output. After the fifth (delay of 5S, 10S, 15S, 20S, 25S) automatic output recovery fails, the load will be locked. If you want the controller to start the automatic recovery process again, restart the controller, or let the controller undergo a change from night to day (nighttime duration > 3 hours).
The controller detects its internal temperature by the internal temperature sensor. The controller stops operating when its internal temperature is higher than 85°C, and resumes operating when its internal temperature is below 75°C.
The internal circuit of this controller is designed with Transient Voltage Suppressors (TVS), which can only protect against high-voltage surge pulses with less energy. If the controller is used in an area with frequent lightning strikes, it is recommended to install an external lightning arrester.

When the control’s internal temperature is 81°C, the charging power reduction mode is turned on.
For every 1°C increase in temperature, the charging power is reduced by 5%, 10%, 20%, and 40% respectively.When the temperature is higher than 85°C , the charging is stopped. While the internal temperature is not more than 75ºC, the controller will resume charging as per the rated charging power. For example, LET-H100HF2R2-HJ 48V system:

4.2 Troubleshooting

Status
PV indicator is fast flashing

Error Code POV

Possible Reasons PV Overvoltage

Troubleshooting
Check whether the connected PV open circuit voltage is higher than the PV maximum open circuit voltage, and the alarm is cleared when the PV open circuit

Guangdong Lesso Energy Storage Technology Co., Ltd.

52

green.
BATT indicator is solid orange.
BATT indicator is solid red. BATT indicator is fast flashing

LET-XB2-HJ Series User Manual

PME RPP PRE
PPL
BUV
CUV
BOD BOF BSF LBVE

PV Work Mode Error PV Reverse Polarity Protection
PV Relay Error
PV Power Low
Battery Undervoltage Alarm (including battery pack Undervoltage alarm)
Cell Undervoltage Protection
Battery Over Discharging Protection
BMS Other Fault BMS Sensor Fault Lithium Battery

voltage is lower than the PV maximum open circuit voltage minus 5V.
Check whether the PV connection method is consistent with the parameter settings of “PCM (PV Connection Mode)”.
Check whether the PV is connected to the battery correctly.
Turn off the controller first, wait for 5 minutes, then turn it on again to check whether it returns to normal. If this error persists, please contact our technical support.
Wait until there is sufficient sunlight to check whether the fault is cleared.
Note: “PPL (PV Power Low) refers to PV power is lower than load power when no battery is connected.
Disconnect the loads connection, and check whether the battery voltage is too low. After the battery is charged and its voltage is restored above “UVAR (Undervoltage Alarm Recovery Voltage)”, it will automatically resume normal operation, or recharge the battery with other methods.
Check the BMS communication status or BMS parameters settings.
Disconnect the loads connection, and check whether the battery voltage is too low. After the battery is charged and its voltage is restored above “LVR (Low Voltage Recovery Voltage)”, it will automatically resume normal operation, or use other methods to recharge the battery.
Check whether the battery BMS connection is normal.
Check whether the lithium battery is

Guangdong Lesso Energy Storage Technology Co., Ltd.

53

red.
BATT indicator is fast flashing green.
BATT indicator is slowly flashing red.

LET-XB2-HJ Series User Manual

BOV COV BOT
BLT COT CLT

Rated Voltage Identification Error
Battery Overvoltage Protection
Cell Overvoltage Protection
Battery Over Temperature
Battery Low Temperature
Cell Over Temperature Protection Cell Low Temperature

connected to the controller correctly or the voltage uploaded by BMS is consistent with the voltage at the controller battery terminals.
Disconnect all charging and measure whether the battery voltage is too high, and check whether the voltage of the connected battery matches the rated voltage level of the controller, or check whether the setting value of the battery “OVD (Overvoltage Disconnect Voltage)” is inconsistent with the battery specifications. After the battery voltage drops below the set value of “OVR (Overvoltage Recovery Voltage)”, the alarm will automatically be cleared.
Check the BMS communication status or BMS parameters settings.
Ensure the battery is installed in a cool and well-ventilated place, check that the battery actual charging and discharging current does not exceed the set values of “Battery Max Charging Current”. (If BMS is connected, “MCC” is the read value from the BMS, which cannot be set. When the battery temperature drops below the “BATT OTPR (Battery Over Temperature Recovery)”, the controller resumes normal charging and discharging control.
Check whether the ambient temperature is lower than the “LTCL (Low Temperature Charging Limit)” and “LTDL (Low Temperature Discharging Limit)”, when the ambient temperature is higher than the “LTCL + 2” or “LTDL + 2”, the battery resumes normal operating.
Check the BMS communication status or BMS parameters settings.

Guangdong Lesso Energy Storage Technology Co., Ltd.

54

LET-XB2-HJ Series User Manual

BATT indicator is slowly flashing green.
—
Yellow Load indicator is off.
PV indicator is fast flashing green. BATT indicator is fast flashing orange.

BCP BDP SDP SLBP BOCD BOCC BLC PIDR LSC LOL
DOT
DCF

Protection

BMS Charging Protection
BMS Discharging Protection
SOC Discharging Protection
SOC Low Battery Protection

Charge the battery to DPRS (Discharging Protection Recovery SOC).
Charge the battery to LBAR (Low Battery Alarm Recovery SOC)

BMS Over Current Discharging Alarm
BMS Over Current Charging Alarm

Check the BMS communication status or BMS parameters settings.

BMS voltage and current limiting parameters are taking effect Parallel ID Repetition
Load Short Circuit
Load Overload
Device Over Temperature
DSP Communication Fault

BMS is normal and no troubleshooting is required.
Check whether the IDs of parallel equipment is repeated.
Disconnect all the loads and turn off the controller, wait for 5 minutes, then turn on the controller again to check whether it returns to normal. If this error persists, please contact our technical support.
Ensure the controller is installed in a cool and well-ventilated place, When the controller temperature drops below the “DOT (Device Over Temperature)”, the controller resumes normal charging control.
Turn off the controller first, wait for 5 minutes, then turn it on again to check whether it returns to normal. If this error persists, please contact our technical support.

Guangdong Lesso Energy Storage Technology Co., Ltd.

55

LET-XB2-HJ Series User Manual
4.3 Maintenance
To maintain long-term working performance, it is recommended to have the following items inspected twice a year. Ensure the airflow around the inverter is not blocked, and remove dirt or debris from the heat sink. Check whether the insulation of exposed cables have been damaged by sunlight, friction with
other surrounding objects, dryness, insects or rodents, etc. Repair or replace the cables if necessary. Check whether the indicator and display are consistent with the actual operation of the equipment, and note that corrective action should be taken in case of inconsistency or error. Check terminals for signs of corrosion, insulation damage, high temperature or burning/ discoloration, tighten terminal screws. Check for signs of dirt, insect nesting and corrosion and clean up as required. If the lightning arrester has failed, replace it in time to avoid lightning strikes’ damage to the controller or even other equipment.
DANGER
Electric shock hazard! Ensure that the power supply of the controller is disconnected when performing the above operations!

Guangdong Lesso Energy Storage Technology Co., Ltd.

56

LET-XB2-HJ Series User Manual

5. Technical Specifications
Model Electrical Parameters
Battery Rated Voltage
Controller Operating Voltage Range
Battery Type
Lithium Battery Type Rated Charging/Discharging Current Rated Charging Power
Maximum Charging Power Rated Load Current Maximum Load Current
PV Maximum Open-circuit Voltage
MPPT Voltage Range
Tracking Efficiency Maximum Conversion Efficiency Full Load Efficiency Temperature Compensation Coefficient Static Loss (Enabled Communication) Static Loss (Disabled Communication) Grounding Type
Dry Contact (Oil Generator)

LET-H50HN2R1-HJ
12/24/48VDC or Auto 8­62V
AGM (Default)/Gel/Flooded/User LiFePO4/Li (NiCoMn)O2/User 50A
650W/12V; 1,300W/24V; 2,600W/48V 650W/12V; 1,300W/24V; 2,600W/48V
50A 50A 200V (@ lowest temperature); 180V (@ 25)(1) (Battery voltage plus 2V, and > 28V) to 144V (@ 25) 99.5% 98.3% 97.1% -3mV//2V (Default)
98mA/12V; 60mA/24V; 46mA/48V
48mA/12V; 25mA/24V; 14mA/48V Common negative grounding Rated value: 5A/30VDC; Maximum value: 0.5A/60VDC

Guangdong Lesso Energy Storage Technology Co., Ltd.

57

LET-XB2-HJ Series User Manual

Communication Method
Mechanical Parameters
Dimension (L × W × H) IP43 (Controller & White Terminal Cover)
Dimension (L × W × H) IP32 (Controller Only)
Mounting Dimension (L × W)
Mounting Hole
Wiring Terminal
Recommended Cable
Weight IP43 (Controller & White Terminal Cover)
Weight IP32 (Controller Only)

RS485 5VDC/200mA (RJ45)
307mm × 253mm × 143mm
307mm × 202mm × 134mm 295mm × 130mm 7mm 6AWG/16mm2 6AWG/16mm2 5.07kg
4.86kg

(1) The controller starts charging the battery when PV voltage is higher than 35V. The controller stops charging the battery when the PV voltage is lower than 25V.

Guangdong Lesso Energy Storage Technology Co., Ltd.

58

LET-XB2-HJ Series User Manual

Model
Electrical Parameters Battery Rated Voltage Controller Operating Voltage Range Battery Type Lithium Battery Type Rated Charging/Discharging Current Rated Charging Power Maximum Charging Power Rated Load Current Maximum Load Current
PV Maximum Open-circuit Voltage

LET-H60LN2R1-HJ LET-H60LN2B1-HJ

LET-H60HN2R1-HJ

12/24/48VDC or Auto 8­62V
AGM (Default)/Gel/Flooded/User LiFePO4/Li (NiCoMn)O2/User

60A

780W/12V; 1,560W/24V; 3,120W/48V 780W/12V; 1,560W/24V; 3,120W/48V

60A 60A

150V (@ lowest temperature); 138V (@ 25)(1)

200V (@ lowest temperature); 180V (@ 25)(1)

MPPT Voltage Range
Tracking Efficiency
Maximum Conversion Efficiency
Full Load Efficiency
Temperature Compensation Coefficient
Static Loss (Enabled Communication)
Static Loss (Disabled Communication)
Grounding Type

(Battery voltage plus 2V, and > 28V) to 108V (@ 25)

(Battery voltage plus 2V, and > 28V) to 144V (@ 25)

99.5%

98.6%

98.1%

98.0%

97.5%

-3mV//2V (Default)

98mA/12V; 60mA/24V; 46mA/48V

48mA/12V; 25mA/24V; 14mA/48V Common negative grounding

Guangdong Lesso Energy Storage Technology Co., Ltd.

59

LET-XB2-HJ Series User Manual

Dry Contact (Oil Generator)
Communication Method
Mechanical Parameters
Dimension (L × W × H) IP43 (Controller & White Terminal Cover)
Dimension (L × W × H) IP32 (Controller Only)
Mounting Dimension (L × W)
Mounting Hole
Wiring Terminal
Recommended Cable
Weight IP43 (Controller & White Terminal Cover)
Weight IP32 (Controller Only)

Rated value: 5A/30VDC; Maximum value: 0.5A/60VDC
RS485 5VDC/200mA (RJ45)

320mm × 263mm × 143mm

320mm × 212mm × 134mm

308mm × 140 mm
7mm 2AWG/35mm2 6AWG/16mm2

5.88kg

5.93kg

5.66kg

5.71kg

(1) The controller starts charging the battery when PV voltage is higher than 35V. The controller stops charging the battery when the PV voltage is lower than 25V.

Guangdong Lesso Energy Storage Technology Co., Ltd.

60

LET-XB2-HJ Series User Manual

Model
Electrical Parameters Battery Rated Voltage Controller Operating Voltage Range
Battery Type

LET-H75LN2R1-HJ

LET-H75HN2R1-HJ

12/24/48VDC or Auto 8­62V
AGM (Default)/Gel/Flooded/User

Lithium Battery Type
Rated Charging/Discharging Current
Rated Charging Power
Maximum Charging Power
Rated Load Current
Maximum Load Current
PV Maximum Open-circuit Voltage

LiFePO4/Li (NiCoMn)O2/User

75A

975W/12V; 1,950W/24V; 3,900W/48V

975W/12V; 1,950W/24V; 3,900W/48V

75A

75A

150V (@ lowest temperature); 138V (@ 25)(1)

200V (@ lowest temperature); 180V (@ 25)(1)

MPPT Voltage Range

(Battery voltage plus 2V, and > 28V) to 108V (@ 25)

(Battery voltage plus 2V, and > 28V) to 144V (@ 25)

Tracking Efficiency
Maximum Conversion Efficiency
Full Load Efficiency
Temperature Compensation Coefficient
Static Loss (Enabled Communication)

98.6% 98.0%

99.5%

98.1% 97.5%

-3mV//2V (Default)

98mA/12V; 60mA/24V; 46mA/48V

Guangdong Lesso Energy Storage Technology Co., Ltd.

61

LET-XB2-HJ Series User Manual

Static Loss (Disabled Communication)
Grounding Type
Dry Contact (Oil Generator)
Communication Method
Mechanical Parameters
Dimension (L × W × H) IP43 (Controller & White Terminal Cover)
Dimension (L × W × H) IP32 (Controller Only)
Mounting Dimension (L × W)
Mounting Hole
Wiring Terminal
Recommended Cable
Weight IP43 (Controller & White Terminal Cover)
Weight IP32 (Controller Only)

48mA/12V; 25mA/24V; 14mA/48V
Common negative grounding Rated value: 5A/30VDC;
Maximum value: 0.5A/60VDC RS485 5VDC/200mA (RJ45)

320mm × 263mm × 158mm

320mm × 212mm × 149mm

308mm × 140mm
7mm 2AWG/35mm2 4AWG/25mm2

6.56kg

6.62kg

6.34kg

6.40kg

(1) The controller starts charging the battery when PV voltage is higher than 35V. The controller stops charging the battery when the PV voltage is lower than 25V.

Guangdong Lesso Energy Storage Technology Co., Ltd.

62

LET-XB2-HJ Series User Manual

Model Electrical Parameters Battery Rated Voltage Controller Operating Voltage Range Battery Type Lithium Battery Type Rated Charging/Discharging Current Rated Charging Power Maximum Charging Power Rated Load Current Maximum Load Current PV Maximum Open-circuit Voltage
MPPT Voltage Range Tracking Efficiency Maximum Conversion Efficiency Full Load Efficiency Temperature Compensation Coefficient Static Loss (Enabled Communication) Static Loss (Disabled Communication) Grounding Type
Dry Contact (Oil Generator)
Communication Method Mechanical Parameters

LET-H80HN2R2-HJ
12/24/48VDC or Auto 8­62V
AGM (Default)/Gel/Flooded/User LiFePO4/Li (NiCoMn)O2/User 80A
1,040W/12V; 2,080W/24V; 4,160W/48V 1,040W/12V; 2,080W/24V; 4,160W/48V
80A 80A 200V (@ lowest temperature); 180V (@ 25)(1) (Battery voltage plus 2V, and > 28V) to 144V (@ 25) 99.5% 98.5% 97.5% -3mV//2V (Default)
98mA/12V; 60mA/24V; 46mA/48V
48mA/12V; 25mA/24V; 14mA/48V Common negative grounding Rated value: 5A/30VDC; Maximum value: 0.5A/60VDC RS485 5VDC/200mA (RJ45)

Guangdong Lesso Energy Storage Technology Co., Ltd.

63

LET-XB2-HJ Series User Manual

Dimension (L × W × H) IP43 (Controller & White Terminal Cover)
Dimension (L × W × H) IP32 (Controller Only)
Mounting Dimension (L × W)
Mounting Hole
Wiring Terminal
Recommended Cable
Weight IP43 (Controller & White Terminal Cover)
Weight IP32 (Controller Only)

352mm × 263mm × 158mm
352mm × 212mm × 149mm 340mm × 140 mm 7mm 2AWG/35mm2 4AWG/25mm2 7.79kg
7.55kg

(1) The controller starts charging the battery when PV voltage is higher than 35V. The controller stops charging the battery when the PV voltage is lower than 25V.

Guangdong Lesso Energy Storage Technology Co., Ltd.

64

LET-XB2-HJ Series User Manual

Model
Electrical Parameters
Battery Rated Voltage
Controller Operating Voltage Range
Battery Type
Lithium Battery Type
Rated Charging/Discharging Current
Rated Charging Power
Maximum Charging Power
Rated Load Current
Maximum Load Current
PV Maximum Open-circuit Voltage

LET-H100LF2R2-HJ LET-H100LF2B2-HJ

LET-H100HF2R2-HJ

12/24/48VDC or Auto 8­62V
AGM (Default)/Gel/Flooded/User LiFePO4/Li (NiCoMn)O2/User

100A

1,300W/12V; 2,600W/24V; 5,200W/48V

1,300W/12V; 2,600W/24V; 5,200W/48V

100A

100A

150V (@ lowest temperature); 138V (@ 25)(1)

200V (@ lowest temperature); 180V (@ 25)(1)

MPPT Voltage Range

(Battery voltage plus 2V, and > 28V) to 108V (@ 25)

(Battery voltage plus 2V, and > 28V) to 144V (@ 25)

Tracking Efficiency
Maximum Conversion Efficiency
Full Load Efficiency
Temperature Compensation Coefficient
Static Loss (Enabled Communication)
Static Loss (Disabled Communication)

98.6% 98.0%

99.5%

98.5% 97.6%

-3mV//2V (Default)

98mA/12V; 60mA/24V; 46mA/48V 48mA/12V; 25mA/24V; 14mA/48V

Guangdong Lesso Energy Storage Technology Co., Ltd.

65

LET-XB2-HJ Series User Manual

Grounding Type
Dry Contact (Oil Generator)
Communication Method
Mechanical Parameters
Dimension (L × W × H) IP43 (Controller & White Terminal Cover)
Dimension (L × W × H) IP32 (Controller Only)
Mounting Dimension (L × W)
Mounting Hole
Wiring Terminal
Recommended Cable
Weight IP43 (Controller & White Terminal Cover)
Weight IP32 (Controller Only)

Common negative grounding Rated value: 5A/30VDC;
Maximum value: 0.5A/60VDC RS485 5VDC/200mA (RJ45)

352mm × 263mm × 158mm

352mm × 212mm × 149mm

340mm × 140mm
7mm 2AWG/35mm2 2AWG/35mm2

7.87kg

7.87kg

7.63kg

7.63kg

(1) The controller starts charging the battery when PV voltage is higher than 35V. The controller stops charging the battery when the PV voltage is lower than 25V.

Environmental Parameters Operating Temperature LCD Operating Temperature Storage Temperature Relative Humidity Altitude

-25 to +60 (> 40 derating) -20 to +70 -30 to +70 5%­95% (N.C.)
< 5,000M (> 2,000m derating)

Guangdong Lesso Energy Storage Technology Co., Ltd.

66

Ingress Protection Pollution Degree Certification Safety EMC FCC ROHS

LET-XB2-HJ Series User Manual
IP43 (Controller & White Terminal Cover); IP32 (Controller Only) II
EN/IEC62109-1 EN61000-6-1/EN61000-6-3 47 CFR Part 15, Subpart B
IEC62321-3-1

Guangdong Lesso Energy Storage Technology Co., Ltd.

67

LET-XB2-HJ Series User Manual

6. Appendices
6.1 Appendix I Dimensions
LET-H50HN2R1-HJ: IP43 (Controller & White Terminal Cover)

(Unit: mm)

LET-H50HN2R1-HJ: IP32 (Controller Only)

134

36

G rounding screw :M 5*12 Ø7
7

130 202

12

295 307

Guangdong Lesso Energy Storage Technology Co., Ltd

68

LET-XB2-HJ Series User Manual
LET-H60LN2R1-HJ / LET-H60HN2R1-HJ / LET-H60LN2B1-HJ: IP43 (Controller & White Terminal Cover)

LET-H60LN2R1-HJ / LET-H60LN2B1-HJ / LET-H60HN2R1-HJ: IP32 (Controller Only)

134

36

212

140

G rounding screw :M 5*12 Ø7
7
308 320

12

Guangdong Lesso Energy Storage Technology Co., Ltd

69

LET-XB2-HJ Series User Manual LET-H75LN2R1-HJ / LET-H75HN2R1-HJ: IP43 (Controller & White Terminal Cover)

LET-H75LN2R1-HJ / LET-H75HN2R1-HJ: IP32 (Controller Only)

149

36

G rounding screw :M 5*12 Ø7 7

140 212

12

308 320

Guangdong Lesso Energy Storage Technology Co., Ltd

70

LET-XB2-HJ Series User Manual LET-H80HN2R2-HJ: IP43 (Controller & White Terminal Cover)

LET-H80HN2R2-HJ: IP32 (Controller Only)

149

G rounding screw :M 5*12

36

212

140

Ø7 7

12

340 352

Guangdong Lesso Energy Storage Technology Co., Ltd

71

LET-XB2-HJ Series User Manual
LET-H100LF2R2-HJ / LET-H100LF2B2-HJ / LET-H100HF2R2-HJ: IP43 (Controller & White Terminal Cover)

LET-H100LF2R2-HJ / LET-H100LF2B2-HJ / LET-H100HF2R2-HJ: IP32 (Controller Only)

149

36

G rounding screw :M 5*12 Ø7 7

212

140

12

340 352

Guangdong Lesso Energy Storage Technology Co., Ltd

72

LET-XB2-HJ Series User Manual

6.2 Appendix II Abbreviation Index
LCD Parameter Setting Abbreviations

Abbreviations BT DFV AFV
PMCC CAE CPE PRCP DRP SCT SBT TU BAUD ADDR PCM SBM UBS BPRO NTM NTH WDM2 WDH2 WDM1 WDH1

Full Name Battery Type DSP Firmware Version ARM Firmware Version Parallel Maximum Charging Current Clear Accumulated Energy Com Port Enable PV Restart Charging Period Data Record Period Screen Cycle Time Screen Backlight Time Temperature Unit Baud rate Address PV Connection Mode Simulate BMS Mode Use BMS Settings BMS Protocol Night Time (m) Night Time (h) Working Duration2 (m) Working Duration2 (h) Working Duration1 (m) Working Duration1 (h)

Guangdong Lesso Energy Storage Technology Co., Ltd

73

LET-XB2-HJ Series User Manual

TCP TOFD TOND MMDS LCM MCC MEC LTDL LTCL LBP DPS LBAS LBAR DPRS FCPR FCPS CDM BCT ECT DVL LVD UVA UVAR LVR BVR FCV BCV

Timing Control Period Turn-Off Delay Turn-On Delay Manual Mode Default Switch Load Control Mode Battery Max Charging Current Manual Equalize Charging Low Temperature Discharging Limit Low Temperature Charging Limit Lithium Battery Protection Discharging Protection SOC Low Battery Alarm SOC Low Battery Alarm Recovery SOC Discharging Protection Recovery SOC Full Charge Protection Recovery SO Full Charge Protection SOC Charging/Discharging Mode Bulk Charging Time Equalization Charging Time Discharging Voltage Limit Voltage Low Voltage Disconnect Voltage Undervoltage Alarm Voltage Undervoltage Alarm Recovery Voltage Low Voltage Recovery Voltage Bulk Recovery Voltage Float Charging Voltage Bulk Charging Voltage

Guangdong Lesso Energy Storage Technology Co., Ltd

74

LET-XB2-HJ Series User Manual

ECV OVR CVL OVD RVL TCC BC ROT RFS

Equalization Charging Voltage Overvoltage Recovery Voltage Charging Limit Voltage Overvoltage Disconnect Voltage Rated Voltage Level Temperature Compensation Coefficient Battery Capacity Remote ON/OFF Terminal Restore Factory Settings

Error Codes Abbreviations

Abbreviations POV PME RPP PRE PPL
BUV
BOV BOD BOT BLT COV CUV CLT COT BOF

Full Name PV Overvoltage PV Work Mode Error PV Reverse Polarity Protection PV Relay Error PV Power Low Battery Undervoltage Alarm (including battery pack Undervoltage alarm) Battery Overvoltage Protection Battery Over Discharging Protection Battery Over Temperature Battery Low Temperature Cell Overvoltage Protection Cell Undervoltage Protection Cell Low Temperature Protection Cell Over Temperature Protection BMS Other Fault

Guangdong Lesso Energy Storage Technology Co., Ltd

75

BSF BCP BDP SDP SLBP BOCD BOCC BLC LSC LOL DOT DCF LBVE

LET-XB2-HJ Series User Manual
BMS Sensor Fault BMS Charging Protection BMS Discharging Protection SOC Discharging Protection SOC Low Battery Protection BMS Over Current Discharging Alarm BMS Over Current Charging Alarm BMS voltage and current limiting parameters are taking effect Load short-circuit Load Over Load Device Over Temperature DSP Communication Fault Lithium Battery Rated Voltage Identification Error Alarm
Any changes without prior notice! Version number: V1.2

Guangdong Lesso Energy Storage Technology Co., Ltd

76

Documents / Resources

LESSO LET-XB2-HJ Series MPPT Solar Charge Controller [pdf] User Manual LET-XB2-HJ, LET-XB2-HJ Series MPPT Solar Charge Controller, LET-XB2-HJ Series, MPPT Solar Charge Controller, Solar Charge Controller, Charge Controller

References

• User Manual