Srne MC Series User manual

MC Series MPPT Solar Charge Controller
User Manual
MC2420N10/ MC2430N10/ MC2440N10/ MC2450N10
Model
MC2420N10
MC2430N10
MC2440N10
MC2450N10
Battery voltage
12V/24V
Max. PV open
circuit voltage
92V(25℃)；100V(Lowest ambient temperature)
Charge current
20A
30A
40A
50A
Max. PV input
power
260W/12V
520W/24V
400W/12V
800W/24V
520W/12V
1040W/24V
660W/12V
1320W/24V
Dear Users:
Thank you very much for choosing our products!

Safety Instructions
1. Applicable voltage of the controller exceeds the safety voltage for human body, so please
read the manual carefully before use and operate the controller only after safety operation
training has been completed.
2. There are no parts inside the controller that need to be maintained or repaired. The user shall
not disassemble and repair the controller.
3. Install the controller indoors to prevent exposure of components and prevent water from
entering the controller.
4. Please install the controller in a well-ventilated place to prevent the heat sink from being
overheated.
5. It is recommended to install a proper fuse or circuit breaker outside the controller.
6. Be sure to disconnect the wiring of PV array and the fuse or circuit breaker near battery
terminal before installation and wiring adjustment of the controller.
7. Check that all wiring is tight after installation to avoid danger of heat accumulation due to
poor connections.
Warning: This operation is dangerous, so before operation, safety
preparations must be made.
Caution: This operation may have a destructive effect.
Reminder: Suggestions and tips for operator.
Contents
1. Introduction 4
1.1. Overview 4
1.2. Features 4
1.3. Appearance 6
1.4. MPPT Technology Introductions 7
1.5. Charging Stage Introductions 9
2. Installation 13
2.1. Installation Precautions 13
2.2. Wire Specifications 14
2.3. Installation and Wiring 14
3. Product Operation and Display 18
3.1. LED Indication 18
∙12
∙Erro! Indicador não definido.
∙Erro! Indicador não definido.
3.2. Keys Operation 20

4. Product Protection and System Maintenance 20
4.1 Protections 20
4.2 System Maintenance 22
5. Technical Parameters 23
5.1 Electrical parameters 23
5.2. Battery type default parameters 23
6. Conversion Efficiency Curve 25
6.1. 12V System 25
6.2. 24V System 25
7. Product Dimensions 26
1. Introduction
1.1. Overview
With industry-leading PowerCatcher MPPT technology, the MC series solar charge
controller enables maximum energy tracking for solar panel. This technology allows the
controller to quickly and accurately track the maximum power point of PV array in any
environment, obtain the maximum energy of solar panel in real time, and significantly
increase energy utilization efficiency of the solar energy system.
This product can be connected to an external LCD screen or Bluetooth communication
module and PC Upper Computer for dynamic display of operating status, operating
parameters, controller logs, control parameters, etc. The user can look up various
parameters and can modify the control parameters as needed to suit different system
requirements.
The controller adopts standard Modbus communication protocol, which is convenient
for the user to view and modify the parameters of the system. Meanwhile, the company
provides free monitoring software that can maximize the convenience for users to meet
different needs of remote monitoring.
The controller provides overall electronic fault self-test and powerful electronic
protection functions which minimize components damage due to installation error and
system failure.
1.2. Features
◆PowerCatcher maximum power point tracking technology allows the controller to track
the maximum power point of solar panels even in a complex environment. Compared
with the traditional MPPT tracking technology, it boasts faster response speed and

higher tracking efficiency.
◆A built-in maximum power point tracking (MPPT) algorithm can significantly increase
energy utilization efficiency of the photovoltaic system, which is about 15% to 20%
higher than traditional PWM charging.
◆It provides an active charging voltage regulation feature. At battery open circuit or
lithium battery BMS overcharge protection, the controller battery terminal will output
the rated charging voltage value.
◆MPPT tracking efficiency is up to 99.9%.
◆Due to an advanced digital power technology, the circuit energy conversion efficiency
is as high as 98%.
◆Available in multiple battery types and support charging procedures of various types of
batteries such as lithium battery, colloidal battery, sealed battery, vented battery, lithium
battery, etc.
◆A current-limited charging mode is available. When the power of solar panel is too
large and the charging current is higher than the rated valve, the controller automatically
reduces the charging power so that the solar panel can operate at the rated charging
current.
◆Support automatic identification of lead-acid battery voltage.
◆External LCD screen or Bluetooth module can be connected for viewing of equipment
operating data and status, and modification of controller parameters is supported.
◆Support standard Modbus protocol to meet communication needs in different
occasions.
◆Built-in over-temperature protection mechanism ensures that when temperature
exceeds the set value of the device, the charging current decreases linearly with the
temperature, thereby reducing the temperature rise of controller and avoiding high
temperature damage.
◆Temperature compensation and automatic adjustment of charge and discharge
parameters help to improve battery life.
◆Solar panel short circuit protection, battery open circuit protection and TVS lightening
protection etc.

1.3. Appearance
Figure 1-1 Controller Appearance and Ports
No.
Names
No.
Names
Solar panel "+"
interface
Communication Interface
Solar panel "-"
interface
Operation keys
Battery "-" interface
PV charging indicator
Battery "+" interface
Battery level indicator
External temperature
sampling interface
Battery type indicator
1.4. MPPT Technology Introductions
The Maximum Power Point Tracking (MPPT for short) system is an advanced
charging technology that enables the solar panel to output more energy by adjusting
operating conditions of the electrical module. Due to non-linear characteristics of
solar array, there is maximum energy output point (maximum power point) of an
array on its curve. Traditional controller (switch charging technology and PWM
charging technology) fails to maintain battery charging at this point, and therefore
the maximum energy of the solar panel cannot be obtained. The solar charge
controller with MPPT control technology, however, can track the array's maximum
power point at all time to obtain the maximum energy to charge the battery.
Erro!
Erro!
Erro!
Erro!
Erro!
Erro!
○,1
Erro!
Erro!
Erro!

Take a 12V system as an example. Peak voltage (Vpp) of the solar panel is about
17V, while the battery voltage is about 12V. In general, when the controller is
charging the battery, the voltage of solar panel is about 12V and does not fully
contribute its maximum power. But, MPPT controller can overcome this problem. It
constantly adjusts the input voltage and current of the solar panel to achieve the
maximum input power.
Compared to the traditional PWM controller, the MPPT controller can provide the
maximum power of the solar panel and thus can provide a larger charging current.
In general, the MPPT controller can improve the energy utilization by 15% -20%
compared with the PWM controller.
Figure 1-2 Solar panel output characteristics curve
In addition, due to the difference in ambient temperature and light conditions, the
maximum power point often changes. The MPPT controller can adjust parameters
according to different conditions from time to time to keep the system near to its
maximum working point. The whole process is fully automatic and does not require
any adjustments by users.
P(W)
I(A)

Figure 1-3 Relationship between solar panel output characteristics and light
Figure 1-4 Relationship between solar panel output characteristics and temperature
1.5. Charging Stage Introductions
As one of the charging stages, MPPT cannot be used alone. It is usually required to
combine boost charge, floating charge, equalizing charge and other charging
methods to complete the battery charging process. A complete charging process
includes: Quick charge, holding charge and floating charge. Charging curve is
shown below:
Figure 1-5 Battery charging stages curve graph
a) Quick charge
In quick charge stage, the battery voltage has not yet reached the set value of full
charge voltage (i.e. equalizing/boost charge voltage) and the controller will perform
MPPT charging, which will provide maximum solar energy to charge the battery.
When the battery voltage reaches the pre-set value, constant voltage charge will

start.
b) Holding charge
When the battery voltage reaches the set value of holding voltage, the controller
will perform constant voltage charging. This process will no longer include MPPT
charging, and the charging current will gradually decrease with time. Holding
charge comes in two stages, i.e. equalizing charge and boost charge. The two stages
are conducted without repetition, in which equalizing charge is started once every
30 days.
●Boost charge
The default duration of boost charge is 2 hours. The customer can also adjust the
holding time and the pre-set value of boost voltage point according to actual needs.
When the duration reaches the set value, the system will switch to floating charge.
●Equalizing charge
Warning: Risk of explosion!
Equalizing vented lead-acid battery may generate explosive gases. So, the
battery compartment must be well ventilated.
Caution: Damage of device!
Equalization can increase the battery voltage to levels that may damage sensitive
DC loads. It is necessary to verify that the allowable input voltage of all system
loads is greater than the equalizing charge set value.
Caution: Damage of device!
Over charge and excessive gas evolution may damage the battery plates and
cause active substances on the battery plate to come off. Equalizing charge may
cause damage if voltage is too high or time is too long. Please carefully check the
specific requirements of battery used in the system.
Certain types of battery benefit from regular equalizing charge, which can stir
electrolyte, balance battery voltage, and complete chemical reaction. Equalizing charge
increases the battery voltage above standard voltage, causing vaporization of battery
electrolyte. If it is detected that the controller automatically controls the next stage to be
equalizing charge, the equalizing charge will last for 120 minutes (default). The
equalizing charge and boost charge are not repeated in a full charge process to avoid too
much gas evolution or battery overheating.
Notes:
1) When the system cannot continuously stabilize the battery voltage at a
constant voltage due to the influence of installation environment or load, the controller
will accumulate time until the battery voltage reaches the set value. When the
accumulated time reaches 3 hours, the system will automatically switch to floating
charge.2) If controller clock is not calibrated, the controller will perform regular
equalizing charge according to its internal clock.
●Floating charge
Floating charge is conducted following the holding charge stage, where the
controller will reduce the battery voltage by reducing charge current and allow the

battery voltage to remain at the floating charge set value. During the floating charge
stage, the battery is charged in a very low voltage to maintain full charge state of the
battery. In this stage, the load can get nearly all of the solar energy. If the load
exceeds the energy that solar panel can provide, the controller will not be able to
maintain the battery voltage in the floating charge stage. When the battery voltage is
as low as the recovery charge set point, the system will exit floating charge stage and
re-enter the fast charge stage.
2. Installation
2.1. Installation Precautions
◆Be very careful when installing the battery. When installing the vented lead-
acid battery, wear protective glasses. Once you touch the battery acid, rinse it with
clean water.
◆Avoid placing metal objects near the battery to prevent battery short circuit.
◆Acid gas may be generated when the battery is charged. So ensure good
ventilation.
◆The battery may generate flammable gas. Please keep away from sparks.
◆Avoid direct sunlight and infiltration of rainwater when installing outdoors.
◆Poor connection points and the corroded wires may cause extreme heat to melt
the wire insulation layer, burn the surrounding materials, and even cause fire.
Therefore, it is necessary to ensure that the connectors are tightened, and the wires
preferably fixed with a cable tie to avoid loose connector caused by wire shaking.
◆In system wiring, output voltage of the component may exceed the safety
voltage of human body. So, it is necessary to use insulated tools and ensure that the
hands are dry.
◆Battery terminal on the controller can be connected with either a single battery,
or a pack of battery. Subsequent instructions in the manual are for a single battery,
but it also applies to a battery pack.
◆Observe the safety recommendations of battery manufacturer.
◆The system connection wires are selected according to the current density not
more than 4A/mm2.
◆Make the controller grounded.
2.2. Wire Specifications
Wiring and installation must comply with national and local electrical code
requirements.
PV and battery connection wires must be selected according to rated current. Refer
to the following table for wiring specifications:
Models
PV
maximum
input
Max. wire
diameter at PV
end
Rated
charge
current
Battery wire
diameter
(mm²/AWG)

current
(mm²/AWG)
MC2420N10
20
5/10
20A
5/10
MC2430N10
30
8/8
30A
8/8
MC2440N10
40
10/7
40A
10/7
MC2450N10
50
12/6
50A
12/6
2.3. Installation and Wiring
Warning: Danger, Explosion! Never install the controller and a vented
battery in the same enclosed space! Also do not install in an enclosed place
where battery gas may collect.
Warning: Danger, High Voltage! Photovoltaic arrays may generate very
high open circuit voltages. Disconnect circuit breaker or fuse before wiring and
be very careful during wiring.
Caution: When installing the controller, ensure that there is enough air
to flow through the controller's heat sink, leaving at least 150mm above and
below the controller to ensure natural convection for heat dissipation. If install
it in a closed box, ensure reliable heat dissipation through the box.
Step 1: Choose an installation location
Avoid installing the controller in a place free of direct sunlight, high
temperature, and water, and ensure good ventilation around the
controller.
Step 2: Mark the mounting position according to the mounting dimensions
of the controller. Drill 4 mounting holes of the appropriate size at the 4
marks. Fix screws into the upper two mounting holes.
Step 3: Fasten the Controller

Align fixing holes of the controller with the two pre-fixed screws and hang
the controller up. And then fix the lower two screws.
Step 4: Wiring
For installation safety, we recommend a wiring sequence as follows;
however, wiring in other sequence instead of this one will not damage the
controller.
Warning: Danger, Electric shock hazards! We strongly recommend connect a
fuse or circuit breaker to the PV array and battery terminals to prevent electric shock
hazards during wiring or error operation, and make sure that fuse or circuit breaker is
disconnected before wiring.
Warning: Danger, High voltage hazards! Photovoltaic arrays may generate
very high open circuit voltages. Disconnect circuit breaker or fuse before wiring and be

very careful during wiring.
Warning: Danger, Explosion hazards! If the positive and negative terminals
of battery and the wires connected to them are short-circuited, it may cause a fire or
explosion. Please be very careful in operation.
Please connect the battery first, and then the solar panel. Please follow the “+”
first and “-” next method when wiring.
When all wires are connected firmly and reliably, check whether the wiring is
proper and whether the polarity is reversed. After confirmation, connect the battery fuse
or circuit breaker and observe whether the LED indicator is on. If not, disconnect the
fuse or circuit breaker immediately and check whether wiring is correct.
As the battery is properly energized, connect the solar panel. If there is sufficient
sunlight, the charge indicator of controller will be steady on or flash and start to charge
the battery.
Warning: When the controller has stopped charging for 10 minutes, reverse
polarity of the battery can damage the controller's internal components.
Notes:
1) Note that the battery fuse shall be installed as close as possible to the
battery terminal. The recommended distance is not more than 150mm.
2) The battery temperature is 25°C (fixed value) when the controller is not
collected to a remote temperature sensor.
3. Product Operation and Display
3.1. LED Indication
There are a total of three indicators on the controller
---PV array indication
Indicate the current charging
mode of controller
---BAT indication
Indicate the current state of
battery.
---BAT Type indication
Indicate the current battery type.
●PV array indication
No.
Indicator status
Charging
status
Steady on
MPPT charge
Slow flash
(On:1s, off: 1s, cycle: 2s)
Boost charge
Single flash
(On:0.1s, off: 1.9s, cycle: 2s)
Floating
charge

快闪Quick flash
(On:0.1s, off: 0.1s, cycle: 0.2s)
Equalizing
charge
Double flash
(On:0.1s, off: 0.1s, then, On:0.1s,
off: 1.7s, cycle: 0.2s)
Current
limiting
charge
Off
No charge
●BAT indication:
Indicator color
Indicator status
Battery status
Green
Steady on
Battery full charge
Yellow
Steady on
Battery voltage normal
Red
Steady on
Battery voltage below
under-voltage point
Quick flash
(On:0.1s, off: 0.1s, cycle:
0.2s)
Battery over-voltage or
over temperature
●BAT Type Indication:
Indicator color
Battery type
Green
Sealed lead-acid battery （SLD）
Yellow
Gellead -acid battery (GEL)
Red
Flooded lead-acid battery (FLD)
Blue
12VLi battery (Default:LiFePo4)
Purple
24VLi battery (Default:LiFePo4)
White
User（self-customized）
3.2. Keys Operation
There is a key on the controller, which is used in conjunction with the battery type
indicator for selection of battery type. The specific operation mode is as follows:
In the current operating state, press and hold the key for 8 seconds. The battery type
indicator (the color displayed is that of the previously saved battery type) starts to flash
(the controller turns off charging and other works and enters idle state). At this point,
each time the key is pressed, the battery type indicator changes a color which
corresponds to a battery type. After the battery type is selected, press and hold the key
for 8 seconds again or maintain no operation for 15 seconds. Then, the controller will
automatically save the currently set battery type and enter the normal operating mode;
In addition, if you press and hold the key for 20s, the controller will restore the factory
default parameters.

4. Product Protection and System Maintenance
4.1 Protections
●Waterproofing protection
Rating: IP32
●Input power limited protection
When the power of solar panel is higher than the rated value, the controller will limit
the power of solar panel within the rated power range to prevent damage by over
current, and the controller enter the current-limiting charge.
●Battery reverse polarity protection
If the battery polarity is reversed, the system will not work but it will not burn out
the controller.
●PV input end voltage is too high
If the voltage at the PV array input end is too high, the controller will automatically
shut off the PV input.
●PV input end short circuit protection
If the voltage at the PV array input end is short circuited, the controller will turn off
charging; after short circuit is removed, charging will automatically recover.
●PV input reverse polarity protection
When the polarity of PV array is reversed, the controller will not be damaged, and
normal operation will continue after wiring error is corrected.
●Night reverse charging protection
Prevent battery discharge through the solar panel at night.
●TVS lightning protection
●Over-temperature protection
When temperature of the controller exceeds the set value, it will reduce charging
power or stop charging.
4.2 System Maintenance
◆In order to maintain the best long-term performance for controller, it is
recommended to conduct inspections twice a year.
◆Make sure the airflow around the controller is not obstructed and remove any
dirt or debris from the heat sink.
◆Check if the insulation layers of all exposed wires are damaged due to sun
exposure, friction with other objects nearby, dry rot, destruction of insects or
rodents, etc. If so, it is necessary to repair or replace the wire.
◆Verify if indicators are consistent with the device operations. Please note to
take corrective actions for any malfunctions or error indications if necessary.
◆Check all wiring terminals for corrosion, insulation damage, signs of high
temperature or burning/discoloration. Tighten terminal screws.

◆Check for dirt, insects nesting and corrosion and clean as required.
◆If the lightning arrester has failed, replace it in time to protect controller and
other devices of the user from be damaged by lightning.
Warning: Danger, electric shock hazards! Make sure that all power supplies
to the controller have been disconnected before check or operation as above.!
5. Technical Parameters
5.1 Electrical parameters
Items
Parameters
Model
MC2420N10
MC2430N10
MC2440N10
MC2450N10
System voltage
12V/24V
Zero load loss
<10mA
Battery voltage
9V~32V
Maximum PV open
circuit voltage
92V(25℃)；100V(Lowest ambient temperature)
Maximum power
point voltage range
（Battery voltage +2V）～72V
Rated charging
current
20A
30A
40A
50A
Maximum PV input
power
260W/12V
520W/24V
400W/12V
800W/24V
550W/12V
1100W/24V
660W/12V
1320W/24V
Charging conversion
efficiency
≤98%
MPPT tracking
efficiency
＞99%
Temperature
compensation
coefficient
-3mv/℃/2V（default）; Lithium battery features no temperature compensation
Operating
temperature
-35℃ ～ +45℃
IP rating
IP32
Weight
600g
700g
800g
900g
Communication
mode
TTL Serial communication
Altitude
≤ 3000 meters
Dimensions
150*105.6*61.5
150*105.6*67.5
183*127*65.5
183*127*69.5
5.2. Battery type default parameters
Comparison of parameters of various types of battery

Set voltage
Battery type
Sealed lead-acid
battery
Colloidal lead-acid
battery
Vented lead-acid
battery
Lithium battery
User defined
Overvoltage
disconnection voltage
16.0V
16.0V
16.0V
——
9～17V
Equalizing charge
voltage
14.6V
——
14.8V
——
9～17V
Boost charge voltage
14.4V
14.2V
14.6V
14.4V
9～17V
Floating charge voltage
13.8V
13.8V
13.8V
——
9～17V
Boost charge recovery
voltage
13.2V
13.2V
13.2V
——
9～17V
Equalizing charge
duration
120 min.
——
120 min.
——
0～600 min.
Equalizing charge
interval
30 days
0 days
30 days
——
0～250D（0
indicates turning
off equalizing
charge function）
Boost charge duration
120 min.
120 min.
120 min.
——
10～600 min.
If a user-defined battery is used, the default voltage parameters of the system are the same as
those of the sealed lead-acid battery. The following logic must be followed when you modify
battery charge and discharge parameters:
Overvoltage disconnection voltage> charge limit voltage ≥ equalizing charge voltage ≥ boost
charge voltage ≥ floating charge voltage> boost charge recovery voltage;
Overvoltage disconnection voltage> Overvoltage disconnection recovery voltage;
6. Conversion Efficiency Curve
6.1. 12V System

6.2. 24V System
7. Product Dimensions