
Table of Content
1. Important Safety Information ................................................... 1
1-1. General Safety Precautions 1
1-2. Precautions When Working with Batteries 1
1-3. Installation 2
2. Functional Characteristics ....................................................... 2
2-1. General Information 2
2-2. Application 3
2-3. Electrical Performance 4
2-4. Mechanical Drawings 8
3. Introduction ............................................................................... 9
3-1. Power ON / OFF / REMOTE (Main) switch 9
3-2. LED Indicator 10
3-3. DIP Switch (S1~S8) Assignment 10
3-4. DC Input - 12
3-5. DC Input + 12
3-6. Chassis Ground: Connect the wire # 8 AWG to vehicle chassis. 13
3-7. AC Output 13
3-8. By-pass AC input 13
3-9. AC input circuit breaker 13
3-10. AC output socket 13
3-11. Reset Button (only to be used for Ethernet interface) 13
3-12, 3-13. CAN1 and CAN2 Port 13
3-14. LCM Port 14
3-15. Green terminal (Remote and Parallel select) 14

3-16. RS-232 Port 15
3-17. Fan Ventilation 16
3-18. Protections Features 16
4. DC Wiring Connections .......................................................... 16
4-1. DC Input Terminals 18
4-2. Hard-wire Installation 19
5. Parallel Mode .......................................................................... 22
5-1. Prepare for Parallel Usage 22
5-2. Wiring for Parallel Usage 23
5-3. Industry Applications 25
6. RS-232 command .................................................................... 26
6-1. RS-232 command introduction 26
7. Troubleshooting...................................................................... 28
8. Warranty .................................................................................. 28

1. Important Safety Information
1-1. General Safety Precautions
Do not expose the Inverter to rain, snow, spray, bilge or dust.
To reduce risk of hazard, do not cover or obstruct the ventilation
openings. Do not install the Inverter in a zero-clearance
compartment. Overheating may take place.
To avoid a risk of fire and electric shock, please make sure that
existing wiring is in good electrical condition; and that wire size is not
undersized. Do not operate the Inverter with damaged or
substandard wiring.
This equipment contains components which can produce arcs or
sparks.
To prevent fire or explosion do not install in compartments containing
batteries or flammable materials or in locations which require ignition
protected equipment. This includes any space containing
gasoline-powered machinery, fuel tanks, joints, fittings, or other
connection between components of the fuel system.
1-2. Precautions When Working with Batteries
If battery acid contacts skin or clothing, wash immediately with soap
and water. If acid enters eye, immediately wash eyes with running
cold water for at least 20 minutes and get medical attention
immediately.
Never smoke or allow a spark or flame in vicinity of battery or engine.
Do not drop a metal tool on the battery. The resulting spark or
short-circuit on the battery or other electrical part may cause an
explosion.
Remove personal metal items such as rings, bracelets, necklaces,
and watches when working with a lead-acid battery.
A lead-acid battery produces a short-circuit current high enough to
weld a ring or similar item to metal causing a severe burn.
WARNING!
Before using the Inverter, read and save the safety
instructions.

The power inverter should be installed in a location that meets the following
requirements:
Dry – Do not allow water to drip or splash on the inverter.
Cool – Ambient air temperature should be between -20℃ and 50℃,
but he cooler the better.
Safety – Do not install batteries in the compartment or other areas
here flammable fumes existence such as fuel storage areas or
engine compartments.
Ventilated – Allow at least one inch of clearance around the Inverter
for air flow. Ensure the ventilation shafts on the rear and bottom of
the unit are not obstructed.
Dust-free – Do not install the Inverter in dusty environments here
dust, wood particles or other filings/shavings are present. The dust
can be pulled into the unit when the cooling fan is in operation.
Close to batteries – Avoid excessive cable lengths but do not install
the inverter in the same compartment as batteries.
Use the recommended wire lengths and sizes (see section 4-3).
Do not mount the inverter where it is exposed to the gases
produced by the battery. These gases are very corrosive and
prolonged exposure will damage the inverter.
2. Functional Characteristics
2-1. General Information
SD-series is new generation power inverter equipped with N+1 parallel power
function , 3-phase capability, and AC transfer switch. SD series is suitable for RV,
Marine and Emergency appliances.
WARNING !
Shock Hazard. Before proceeding further, carefully check that the
inverter is NOT connected to any batteries, and that all wiring is
disconnected from any electrical sources . Do not connect the
output terminals of the inverter to an incoming AC source.

Features
Parallel redundancy design for power expansion
Multiple industrial applications that create 1Ф3ω / 3Ф4ω power systems
User-friendly remote control
Automatic master mechanism to eliminate single point failure and optimize
reliability
Built-in ATS and AC circuit breaker
Optional STS module, transfer time is less than 4ms.
RS-232 communication
Input & output fully isolation
Output voltage / power saving mode is selectable by DIP switch and remote
control (CR-10)
Input Protection: Reverse Polarity (Fuse) / Under Voltage / Over Voltage
Protection
Output Protection: Short Circuit / Overload / Over Temperature / Over Voltage
Protection
To get the most out of the power inverter, it must be installed and used properly.
Please read the instructions in this manual before installation and operation of this
model.
2-2. Application
Power tools–circular saws, drills, grinders, sanders, buffers, weed
and hedge trimmers, air compressors.
Office equipment – computers, printers, monitors, facsimile
machines, scanners.
Household items – vacuum cleaners, fans, fluorescent and
incandescent lights, shavers, sewing machines.
Kitchen appliances – coffee makers, blenders, ice markers,
toasters.
Industrial equipment – metal halide lamp, high pressure sodium
lamp.
Home entertainment electronics – television, VCRs, video games,
stereos, musical instruments, satellite equipment.
Vehicle, yacht and off-grid solar power systems.

2-3. Electrical Performance
2500W
(de-rating after 40°C, refer to de-rating curve)
Output
Voltage
(@rated VDC)
100 / 110 / 115 / 120VAC ±3%
200 / 220 / 230 / 240VAC ±3%
Total
Harmonic
Distortion
(THD)
< 3% (@rated / VDC, linear load)
No load
Power
Consumption
100 / 110 / 115 / 120VAC ±12.5%
200/220/230 /240VAC ±12.5%
Standard ATS : Inverter to utility AC: 8~10ms.; Utility AC to inverter:
16~50ms.
Optional STS mode : <4 ms

Reverse Polarity (Fuse) / Under Voltage / Over Voltage Protection / AC
over current (Breaker)
Short Circuit / Overload / Over Temperature / Over Voltage Protection
-20 ~ +60°C; refer SD2500 power de-rating curve
Certified EN 55014, EN 61000-3-2,
EN 61000-3-3;
EN 61000-4-2, 3, 4, 5, 6, 11
Input voltage level, output load level and faulty status
283x128.4x436 mm / 11.146x5.056x17.156 Inch
Load & Thermal control fan
RS-232 (RJ-11 type connector), Ethernet (Optional)
*Note: The specifications are subject to change without prior notice.
All the test environments are conducted under the rated power operation conditions.

3500W
(de-rating after 35°C, refer to de-rating curve for 12V)
(de-rating after 40°C, refer to de-rating curve for 24V and 48V)
Output
Voltage
(@rated VDC)
100 / 110 / 115 / 120VAC ±3%
200 / 220 / 230 / 240VAC ±3%
Total
Harmonic
Distortion
(THD)
< 3% (@rated / VDC, linear load)
No load
Power
Consumption
100/110/115 /120VAC ±12.5%
200/220/230/240VAC ±12.5%
Standard ATS : Inverter to utility AC: 8~10ms.; Utility AC to inverter:
16~50ms.
Optional STS mode : <4 ms

Reverse Polarity (Fuse) / Under Voltage / Over Voltage Protection / AC
over current (Breaker)
Short Circuit / Overload / Over Temperature / Over Voltage Protection
-20 ~ +60°C; refer SD3500 power de-rating curve
Certified EN 55014, EN 61000-3-2,
EN 61000-3-3;
EN 61000-4-2, 3, 4, 5, 6, 11
Input voltage level, output load level and faulty status
283x128.4x496 mm / 11.146x5.056x19.527 inch
Load & Thermal control fan
RS-232 (RJ-11 type connector), Ethernet (Optional)
*Note: The specifications are subject to change without prior notice.
All the test environments are conducted under the rated power operation conditions.

Power ON/OFF/REMOTE (Main)
switch
CAN2 Port (only to be used in parallel
mode)
CAN1 Port (only to be used in parallel
mode)
LCM Port (Connection for LCD remote
control panel)
Green terminal (Remote and Parallel
select)
3-1. Power ON / OFF / REMOTE (Main) switch:
A. Before installing the inverter, please ensure the main switch is in the OFF
position.
B. Before using the remote unit, please ensure the main switch is in the
REMOTE position.

3-3. DIP Switch (S1~S8) Assignment
AC output voltage setting
AC output voltage setting
AC output frequency setting
To set-up 3 Phase output or Energy-saving level
To set-up 3 Phase output or Energy-saving level
To set-up 3 Phase output or Energy-saving level
To set-up DIP Switch S4~S6 for power saving or 3 Phase output
To set-up function parameters adjustment via LCM or DIP switch

3-3-1 DIP switch Set-up
3-3-2 Power Saving Mode
Power Saving Mode is adjustable and set by the Dip Switches,S4, S5 and S6 on the
front panel. Example SD2500: Saving set 2%, the load is below 40W 10 sec. will into
saving mode, more than 80W or more leave saving mode.
X X X 0 0 0 0 X Power saving DISABLE
Go in power saving mode when output
load is under 2% of rating power
Go in power saving mode when output
load is under 3% of rating power
Go in power saving mode when output
load is under 4% of rating power
Go in power saving mode when output
load is under 5% of rating power
Go in power saving mode when output
load is under 6% of rating power
Go in power saving mode when output
load is under 7% of rating power
Go in power saving mode when output
load is under 8% of rating power
0 0 X X X X X X AC output voltage : 100VAC/200VAC
0 1 X X X X X X AC output voltage : 110VAC/220VAC
1 0 X X X X X X AC output voltage : 115VAC/230VAC
1 1 X X X X X X AC output voltage : 120VAC/240VAC
X X 0 X X X X X AC output frequency : 50Hz
X X 1 X X X X X AC output frequency : 60Hz
Power saving mode setting (S4~S6); No
master-slave in parallel
X X X X X X 1 X 3 Phase output setting (S4~S6)
X X X X X X X 0 Adjust function parameters via LCM
X X X X X X X 1 Adjust function parameters via DIP switch

3-3-3 S4~S6 Set-up for 3 Phase output
Master (0°); "R" Phase
to be used for 1Ø 3W output in series
connection(Master) or 3Ø 4W output
connection("R" Phase)
Slave (0°) with current sharing
to be used in parallel connection only
Slave (0°), to be used for 1Ø 3W output in
series connection(L-NL-N)
Slave (180°), to be used for 1Ø 3W output
in series connection(L-NN-L)
Slave (-120°), "S" Phase
to support "S" Phasebe(-120°) in 3Ø 4W
output connection
Slave (120°), "T" Phase
to support "T" Phasebe(120°) in 3Ø 4W
output connection
3-3-4 Parameter select: “S8” select SD’s parameter setting by dip switch or
LCM
3-4. DC Input - : (please refer to DC wiring connections on p.16)
3-5. DC Input + : (please refer to DC wiring connections on p. 16)

3-6. Chassis Ground: Connect the wire # 8 AWG to vehicle chassis.
3-7. AC Output : (Please refer to Hard wiring connections on p. 19)
3-8. By-pass AC input: (please refer to Hard wiring connections on p. 19)
3-9. AC input circuit breaker :
The AC input circuit breaker protects the model from overload. When an
overload condition exists, the circuit breaker stops supplying output AC grid
power. To reset it, push the circuit breaker switch then the model will be back
in normal operation. The source fault should be corrected before you reset it.
3-10. AC output socket : (please refer to Hard wiring connections on p. 19)
3-11. Reset Button (only to be used for Ethernet interface)
The Reset Button is to be used to resume the IP address to factory default
value:
3-12, 3-13. CAN1 and CAN2 Port: (only to be used in parallel mode)
1. Before using parallel mode, you need to ensure the green terminal’s
parallel jump status is set to ON.
2. Use the RJ-45 line to link one of the SD Series CAN1 to the other CAN2.
WARNING!
Operating the inverter without a proper ground connection may
cause electrical safety hazard.

3-14. LCM Port:
Connection for LCD remote control panel, can you set and display the SD-series
operation status.
The cables should be as short as possible (less than 32.8 feet / 10 meters)
so that they can handle the signal.
3-15. Green terminal (Remote and Parallel select)

3-15-1 Parallel Jump Function (please refer to section 3-6 for further
detailed info.)
1. Before installing the inverter, you need to ensure the main switch is in
the OFF position.
2. Use 20 ~ 24 #AWG wire to connect the parallel jump terminal.
3-15-2 Remote Control Function
1. Before installing the inverter, please ensure that the main switch is in
the OFF position.
2. Before using the remote control terminal, please ensure the main
switch is in the REMOTE position.
3. Use 20 ~ 24 #AWG wire to connect the remote control terminal.
4. Remote control ON/OFF inverter setup status.
*NOTE: The above 4 methods can be used to turn ON/OFF.
3-16. RS-232 Port
RS-232 Port: Serial port monitoring and control through computer’s interface.

The connection between this SD-series and the computer is as follows:
3-17. Fan Ventilation
The rear panel must keep the distance at least 1 inch from any surrounding
items.
3-18. Protections Features
*OVA only LED prompt, no beeper alarm.
4. DC Wiring Connections
Follow the instructions to connect the battery cables to the DC input terminals of the
Inverter. The cable should be as short as possible (less than 6 feet / 1.8 meters
ideally) so that it can handle the required current in accordance with the electrical
codes or application regulations. Inappropriate length of cables will reduce the

inverter performance such as poor surge capability, frequent low-input voltage
warnings, and shut-down. UVP warning occurs when DC voltage drops across the
cables from the batteries to inverter?
The longer or the narrower the cable is, the more the voltage drops. Increasing your
DC cable diameter will help to improve the situation will help improve the situation.
The following are recommended cable diameter for the best performance of the
inverter. (Applies to both 120V and 230V versions)
Connect the cables to the power input terminals on the front panel of the inverter.
The red terminal is positive (+) and black terminal is negative (-).
Insert the cables into the terminals and tighten the screw to clamp the wires
securely.
Also, only use high quality copper wire and keep the cable length short - maximum
of 3 - 6 feet.
WARNING!
1. Make sure all the DC connections are tight (torque to 11 ft-lbs,
15 Nm Max.). Loose connections could overheat and result in a
potential hazard.
2. The installation of a fuse must be on the positive cable. Failure
to place a fuse on “+” cables running between the inverter and
battery may cause damage to the inverter and will void warranty.

Do not place anything
between battery cable
lug and terminal
surface.
Assemble exactly as
shown.
Fig. 1: Battery to
inverter connection
4-1. DC Input Terminals:
Connect DC input terminals to 12V / 24V / 48V battery or other power sources.
[ + ] represents positive, [ - ] represents negative. Reverse polarity connection
can blow the internal fuse and may damage the inverter permanently.
WARNING!
During the first installation, it is normal to experience a small
spark is a normal phenomenon because the internal capacitors
charging. Do not be concerned.

4-2. Hard-wire Installation:
4-2-1 SD series provides the flexibility of hard-wire connection, and
this function will make external control panel wiring easier.
Step 1. > Remove the four screws of AC wiring compartment and pull it out with
care.
Fig 2. Pull out AC wiring
compartment
Step 2. > Pull the line through the snap bushing of the AC wiring compartment
cover then follow below picture operation.

100VAC~120VAC / 200VAC~240VAC System
NOTE:
The only difference between 110V and 220V is within the AC Input breaker L
or N and thus will not affect the wiring configuration.
4-2-2 Connect AC output and AC input wiring to the SD series terminals.
Please take the following information as your reference.
Within 16 feet / AWG#
200-240VAC:12AWG
100-120VAC:10AWG
Green / Yellow or
Bare copper
CAUTION!
It is advised that all the electrical installation should conform to the local electrical
codes and should be carried out by a certified technician.
When the unit is feeding the internally inverted voltage, the current carrying
conductors connected to the “L” and “N” terminals of the AC output will be isolated
from the metal chassis of the inverter. Hence, during this condition, when the metal
chassis of the inverter is connected to the earth ground, the “N” terminal of the AC
output will not be grounded (bonded) to the earth ground. Under this condition, the
“N” terminal of the AC output will not be a Neutral in the true sense. Do not touch
this terminal as it will be at an elevated voltage (almost half the value the AC output
voltage) with respect to the metal chassis / earth ground and may produce an
electrical shock when touched!
When the unit is transferring power from the AC input source, the grounding
condition of the “N” terminal of the AC output will be the same as the condition of

the “N” terminal of the AC input source. If the AC input source is the power supplied
from the utility, the “N” terminal would be a Neutral in the true sense. It will normally
be bonded to the earth ground and will read almost 0 V with respect to the earth
ground. In this case, touching this terminal will not be a shock hazard.
4-3-3 AC output and terminals of the SD series, you can use both the
front wiring terminal and outlet, as they are connected in parallel.
Note: if input current over than limit current, please adopt choose to Outlet Adaptor
with 2 Sockets.
WARNING!
When using full power, it is recommended to use the wiring
terminal.

5. Parallel Mode
5-1. Prepare for Parallel Usage
1. Before setting, you need to ensure that the main switch is”OFF”.
2. Before using the parallel function, you need to set the parallel jump of the
green terminal the status of which must be “ON”, if the between in another
SD is set to ”OFF” which is termination resistors.
3. Before using the parallel function, you need to set voltage and frequency of
all units’ DIP switches to the same selection < refer to section 3-1-7 and
3-1-8>
4. Check RJ-45 line connects already < refer to section 3-1-6. >
Example: If three SD inverters are paralleled, setup green terminal.

* If you parallel N units, the first (unit 1) and the last unit (unit N) must set parallel
jumper in ON position.
NOTE:
SD series can be used for N+1 (N≦14) redundancy and the ability of
enlarge the capacity (Users can install maximum 15 units of inverters
together in parallel in order to provide the power expansion).
5-2. Wiring for Parallel Usage
5-2-1 Connection method
1. AC OUTPUT connector setup: Line link to Line; Neutral link to Neutral.
2. AC INPUT connector setup: Line link to Line; Neutral link to Neutral.
3. Battery connector setup: POS+ link to POS+; NEG - link to NEG –
Wring manner:
5-2-2 Connection Diagram
Recommended use only one
battery-bank source

Not prefer to use different battery-bank
configuration because batteries voltage is
difficult to control.

5-2-3 Remove Parallel Connection
1. If “A” and “B” was used in parallel, we only need to operate one of them.
2. In the parallel mode, the first SD turned on will be the master.
3. If we just want to use only one of SDs, we can just remove RJ45 cable,
but make sure the operation is performed in shut-down mode.
5-3. Industry Applications
The SD series create 1Ф3ω
power system, L1-L2 Voltage is
L1-L2 double.
Example:
SD2500-124 set output 100V /
50Hz
The L1-N:100V / 50Hz
The SD series creates 3Φ4ω
power system.
Example:
SD2500-224 set output 230V /
50Hz
The phase voltage is 230V /
50Hz
L1-L2, L1-L3, L2-L3

1Φ3ω do not support N+1
operation, maximum of two SD
inverters, THD < 4%
3Φ4ω do not support N+1
operation, maximum of three SD
inverters, THD < 4%
**DIP switch (S7) must be set
to “1” in this scenario**
S4 0 1 1 S5 0 0 0 S6 0 0 1 S7 1 1
6. RS-232 command
6-1. RS-232 command introduction
6-1-1 RS232 command:
Command format:

This unit uses high-level language commands with a CR (0DH) and LF
(0AH) as the end of the command.
The system would interpret and execute the command only after these two
characters are received. After the unit execute the command, it would
send a response string to the computer. The response string is as
follows:
= > CR LF: Command executed successfully ? > CR LF: Command error,
not accepted ! > CR LF: Command correct but execution error (e.g.
parameters out of range).
If the command needs any information from the unit, the unit would send
the information back to the computer (with CR and LF) and then send the
response string to the computer.
6-1-2 RS-232 Command format:
This unit supports the following command format.
There should always be a CR (0DH) and a LF (0AH) appended to the
command while sending the command to this unit.
Command Table
Note: A space (ASCII code 20H) is needed between Power and <value>
Example: Command to query the Functions No: Format: FUNC?
After “Enter”, the unit’s “Function Code” appears on the PC screen.
6-1-3 Command for accessing Setup Menus and adjusting values:
1. Select the Setup Menus with the help of Function Codes:
Format: FUNC <Function Code>
After “Enter”, the Setup Menu for the Function Code will be called.
The <Function Code>= 0~18, <follows 5.3.5 Display tree>
2. Command to query the Functions No:
Format: FUNC?
After “Enter”, the unit’s “Function Code” appears on the PC screen.

3. Command to query the set value of the Function:
Format: SETT?
After “Enter”, the existing set value of the function appears on the PC
screen.
4. Command to set or adjust the value of the Function:
Format: SETT <value>
After “Enter”, the new value of the Function is set Choose the <value>
of the function please refer (5.3.8 Parameter Setting).
7. Troubleshooting
A. Power status red light is
blinking fast.
Over input voltage. (OVP)
Check input voltage
Reduce input voltage.
B. Power status red light is
Blinking slowly.
Recharge battery. Check
connections and cables.
C. Power status red light is
blinking Intermittently.
Improve ventilation. Make
sure ventilation, shafts of the
inverter are not obstructed.
Lower ambient temperature.
D. Power status is solid red
Short circuit.
Wiring error.
Over Loading (OLP)
Check AC wiring
for short circuit.
Reduce load.
8. Warranty
We guarantee this product against defects in materials and workmanship for a period of
24 months from the date of purchase. Please contact with your local COTEK authorized
distributor for RMA (Return material Authorization) service. Please note that COTEK will
ensure our products are operational before delivery and the warranty service is offered to
the unit which has defect caused under normal use, in the judgment of COTEK’s
technician. The warranty is null and void under the following circumstances:
(a) If the unit has been damaged through abuse, misuse, negligence (such as bumping,
wetting), fault voltage supply, air/water pollution accidents and natural calamities.
(b) If the serial number has been altered, effaced or removed.

No. 33, Rong Hsin Rd., Bade City, Taoyuan County, Taiwan
Phone:886-3-3661581 FAX:886-3-3676029
http:// www.cotek.com.tw
2013.06._A0