Cotek SK Series User Manual

SK Series

Pure Sine Wave Inverter

User’s Manual

Contents

Important Safety

1.

1

Instructions………………………………………………

1-1 General Safety Precautions…………………. 1
1-2 Precautions When Working With Batteries… 1

2. Features…………………………………………………………………... 2
2-1 Application………………………………..…… 2
2-2 Electrical Performance……………..………… 3~7
2-3 Mechanical Drawings………………………… 8~9

3. Introduction……………………………………………………………… 10
3-1 Front Panel Operations……………………… 10~13
3-2 Rear Panel Operations………………….…… 14~15
3-3 Protections Features…………………….…… 15
3-4 Installation……………………………………… 16
3-5 Making DC Wiring Connections ………..….. 17~19
3-6 AC Safety Grounding………………………… 20~21
3-7 Inverter Operation……………………….…… 21

4. Troubleshooting guide……………………………………………… 22

5. Maintenance…………………………………………………………… 23

6. Warranty……………………………………………………………… 23

7. Appendices…………………………………………………………….

CE (LVD EN60950-1) Declaration of

7-1

Conformity……………………………..……

7-2 FCC Declaration of Conformity…………..
7-3 e-mark (e13) Declaration of Conformity…
7-4 UL (UL458) NOTICE OF COMPLETION..

1. Important Safety Instructions

1-1. General Safety Precautions

1-1-1. 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 result.

1-1-2. To avoid a risk of fire and electronic shock. 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.

1-1-3. 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, or joints, fittings, or other connection between
components of the fuel system.

1-2. Precautions When Working with Batteries

1-2-1. If battery acid contacts skin or clothing, wash immediately with

soap and water. If acid enters eye, immediately flood eye with
running cold water for at least 20 minutes and get medical
attention immediately.

1

1-2-2. Never smoke or allow a spark or flame in vicinity of battery or

engine.

1-2-3. Do not drop a metal tool on the battery. The resulting spark or

short-circuit on the battery of other electrical part may cause an
explosion.

1-2-4. 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 the like to metal, causing a severe burn.

WARNING!
Before using the Inverter, read and

save the safety instructions.

2. Features

Pure sine wave output (THD < 3%)

Output frequency：50 / 60Hz switch selectable

Input & output fully isolation design
Low power “ Power Saving Mode “ to conserve energy
High efficiency 89~94%
Capable of driving highly reactive & capacitive loads at start moment.
Tri-Color indicators display input voltage & output load level
Loading controlled cooling fan
Advanced microprocessor
Protection：Input low voltage Overload Short circuit

Low battery alarm Input over voltage Over temperature

2-1. Application

2-1-1. Power tools – circular saws, drills, grinders, sanders, buffers,

weed and hedge trimmers, air compressors.

2-1-2. Office equipment – computers, printers, monitors, facsimile

machines, scanner.

2-1-3. Household items – vacuum cleaners, fans, fluorescent and

incandescent lights, shavers, sewing machines.

2-1-4. Kitchen appliances – coffee makers, blenders, ice markers,

toasters.

2-1-5. Industrial equipment – metal halide lamp, high – pressure

sodium lamp.

2-1-6. Home entertainment electronics – television, VCRs, video

games, stereos, musical instruments, satellite equipment.

2-2. Electrical Performance

Specification Model No.

Item SK700-112 SK700-124 SK700-148 SK700-212 SK700-224 SK700-248

Continuous Output Power 700W

Maximum Output Power (3Min.) 800W

Surge Rating 1400W
Input voltage 12V 24V 48V 12V 24V 48V

Output Voltage

Frequency

(Switch Selectable)

Output Waveform Pure Sine Wave ( THD < 3% )

Efficiency (full load) 89.0% 91.0% 92.0% 91.0% 93.0% 94.0%

No Load Current Draw 1.25A 0.64A 0.31A 1.20A 0.60A 0.28A

Stand-By Current Draw 0.25A 0.15A 0.08A 0.25A 0.15A 0.08A

Input Voltage Regulation

Input Level Indicator Red / Orange / Green LED

Failure Indicator Red LED

Protection

Remote Control Unit CR-6 / CR-7 / CR-8 Optional

100 / 110 / 120V +/- 3% 220 / 230 / 240V +/- 3%

50 / 60Hz +/- 0.05%

10.5-15
VDC

Overload, Short Circuit, Reverse Polarity (Fuse),
Over / Under Input Voltage, Over Temperature.

21.0-30
VDC

Load Level Indicator

42-60

VDC

10.5-15
VDC

21.0-30
VDC

42-60

VDC

Safety UL458 EN60950-1

EMC FCC Class A

Operating Temperature Range

Storage Temperature Range

Cooling Loading controlled cooling fan

Dimensions 295(L)*180(W)*72(H)mm / 11.61(L)*7.09(W)*2.83(H) Inch

Weight 2.7kg / 5.4 Lbs.

Note: The specifications are subject to change without notice

EN55022: 1997
EN55024: 1997
EN61000-3-2: 1998
EN61000-3-3: 1995

0 - 40 ℃

-30℃ to 70℃

e-Mark

Specification Model No.

Item

Continuous Output Power 1000W

Maximum Output Power

(3Min.)
Surge Rating 2000W
Input voltage 12V 24V 48V 12V 24V 48V

Output Voltage

Frequency

(Switch Selectable)

Output Waveform Pure Sine Wave ( THD < 3% )

Efficiency (full load) 89.0% 92.0% 93.0% 91.0% 94.0% 95.0%

No Load Current Draw 1.43A 0.75A 0.38A 1.25A 0.65A 0.35A

Stand-By Current Draw 0.25A 0.15A 0.09A 0.25A 0.15A 0.09A

Input Voltage Regulation

SK1000-

112

100 / 110 / 120V +/- 3% 220 / 230 / 240V +/- 3%

10.5-15
VDC

SK1000-

124

21.0-30
VDC

SK1000-

148

50 / 60Hz +/- 0.05%

42-60

VDC

SK1000-

212

1150W

10.5-15
VDC

SK1000-

224

21.0-30
VDC

SK1000-

248

42-60

VDC

Input Level Indicator Red / Orange / Green LED

Load Level Indicator

Failure Indicator Red LED

Protection

Remote Control Unit CR-6 / CR-7 / CR-8 Optional

Safety UL458 EN60950-1

EMC FCC Class A

Operating Temperature Range

Storage Temperature Range

Cooling Loading controlled cooling fan

Dimensions 383(L)*182(W)*88(H)mm / 15.08(L)*7.17(W)*3.46(H) Inch

Weight 4 kg / 8.8 Lbs.

Overload, Short Circuit, Reverse Polarity (Fuse),
Over / Under Input Voltage, Over Temperature.

EN55022: 1997
EN55024: 1997
EN61000-3-2: 1998
EN61000-3-3: 1995

0 - 40 ℃

-30℃ to 70℃

Note: The specifications are subject to change without notice.

e-Mark

Specification Model No.

Item

Continuous Output Power 1500W

SK1500-

112

SK1500-

124

SK1500-

148

SK1500-

212

SK1500-

224

SK1500-

248

Maximum Output Power

(3Min.)
Surge Rating 3000W
Input voltage 12V 24V 48V 12V 24V 48V

Output Voltage

Frequency

(Switch Selectable)

Output Waveform Pure Sine Wave ( THD < 3% )

Efficiency (full load) 88.0% 91.0% 92.0% 90.0% 93.0% 94.0%

No Load Current Draw 1.45A 0.75A 0.40A 1.40A 0.70A 0.40A

Stand-By Current Draw 0.28A 0.15A 0.09A 0.28A 0.15A 0.09A

Input Voltage Regulation

Input Level Indicator Red / Orange / Green LED

100 / 110 / 120V +/- 3% 220 / 230 / 240V +/- 3%

50 / 60Hz +/- 0.05%

10.5-15
VDC

21.0-30
VDC

Load Level Indicator

42-60

VDC

1725W

10.5-15
VDC

21.0-30
VDC

42-60

VDC

Failure Indicator Red LED

Protection

Remote Control Unit CR-6 / CR-7 / CR-8 Optional

Safety UL458 EN60950-1

EMC FCC Class A

Operating Temperature Range

Storage Temperature Range

Cooling Loading controlled cooling fan

Dimensions 415(L)*191(W)*88(H)mm / 16.34(L)*7.52(W)*3.46(H) Inch

Weight 4.8 kg / 10.56 Lbs.

Overload, Short Circuit, Reverse Polarity (Fuse),
Over / Under Input Voltage, Over Temperature.

EN55022: 1997
EN55024: 1997
EN61000-3-2: 1998
EN61000-3-3: 1995

0 - 40 ℃

-30℃ to 70℃

Note: The specifications are subject to change without notice.

e-Mark

Specification Model No.

Item

Continuous Output Power 2000W

Maximum Output Power

(3Min.)
Surge Rating 4000W
Input voltage 12V 24V 48V 12V 24V 48V

Output Voltage

Frequency

(Switch Selectable)

Output Waveform Pure Sine Wave ( THD < 3% )

Efficiency (full load) 89.0% 92.0% 93.0% 91.0% 94.0% 95.0%

No Load Current Draw 2.8A 1.5A 0.7A 2.64A 1.32A 0.65A

Stand-By Current Draw 0.60A 0.30A 0.15A 0.60A 0.25A 0.15A

Input Voltage Regulation

SK2000-

112

100 / 110 / 120V +/- 3% 220 / 230 / 240V +/- 3%

10.5-15
VDC

SK2000-

124

21.0-30
VDC

SK2000-

148

50 / 60Hz +/- 0.05%

42-60

VDC

SK2000-

212

2300W

10.5-15
VDC

SK2000-

224

21.0-30
VDC

SK2000-

248

42-60

VDC

Input Level Indicator Red / Orange / Green LED

Load Level Indicator

Failure Indicator Red LED

Protection

Remote Control Unit CR-6 / CR-7 / CR-8 Optional

Safety UL458 EN60950-1

EMC FCC Class A

Operating Temperature Range

Storage Temperature Range

Cooling

Dimensions 422(L)*208(W)*166(H)mm / 16.6(L)*8.18(W)*6.53(H) Inch

Weight 9 kg / 19.8 Lbs.

Overload, Short Circuit, Reverse Polarity (Fuse),
Over / Under Input Voltage, Over Temperature.

EN55022: 1997
EN55024: 1997
EN61000-3-2: 1998
EN61000-3-3: 1995

0 - 40 ℃

-30℃ to 70℃

Loading controlled cooling fan ( 65℃ ON , 45℃ OFF)

Note: The specifications are subject to change without notice.

e-Mark

Specification Model No.

Item

Continuous Output Power 3000W

Maximum Output Power

(3Min.)
Surge Rating 6000W
Input voltage 12V 24V 48V 12V 24V 48V

Output Voltage

Frequency

(Switch Selectable)

Output Waveform Pure Sine Wave ( THD < 3% )

Efficiency (full load) 88.0% 91.0% 92.0% 90.0% 93.0% 94.0%

No Load Current Draw 2.0A 1.6A 0.8A 2.8A 1.5A 0.7A

Stand-By Current Draw 0.55A 0.35A 0.19A 0.55A 0.35A 0.19A

Input Voltage Regulation

SK3000-

112

100 / 110 / 120V +/- 3% 220 / 230 / 240V +/- 3%

10.5-15
VDC

SK3000-

124

21.0-30
VDC

SK3000-

148

50 / 60Hz +/- 0.05%

42-60

VDC

SK3000-

212

3450W

10.5-15
VDC

SK3000-

224

21.0-30
VDC

SK3000-

248

42-60

VDC

Input Level Indicator Red / Orange / Green LED

Load Level Indicator

Failure Indicator Red LED

Protection

Remote Control Unit CR-6 / CR-7 / CR-8 Optional

Safety UL458 EN60950-1

EMC FCC Class A

Operating Temperature Range

Storage Temperature Range

Cooling Loading controlled cooling fan

Dimensions 452(L)*208(W)*166(H)mm / 17.80(L)*8.18(W)*6.53(H) Inch

Weight 9.8 kg / 22 Lbs.

Overload, Short Circuit, Reverse Polarity (Fuse),
Over / Under Input Voltage, Over Temperature.

EN55022: 1997
EN55024: 1997
EN61000-3-2: 1998
EN61000-3-3: 1995

0 - 40 ℃

-30℃ to 70℃

Note: The specifications are subject to change without notice.

e-Mark

8

2-3. Mechanical Drawings

3. Introduction

This power inverter series is a the member of the most advanced line of
mobile AC power systems available.

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 this
model.

3-1. Front Panel Operations：

3-1-1. Front view：

3-1-2. ON / OFF/ REMOTE (Main) switch：

a. Before installing the inverter, make sure the main switch
must

be “OFF”.
b. Before using the remote unit, make sure the main switch
must be “ REMOTE”.

3-1-3. Input Level：Display Input Voltages

LED Status DC 12V DC 24V DC 48V

RED Blink (slow) 10.5~10.9 21.0~21.8 42.0~43.6

RED 10.9~11.3 21.8~22.6 43.6~45.2

ORANGE 11.3~12.0 22.6~24.0 45.2~48.0

GREEN 12.0~14.0 24.0~28.0 48.0~56.0

ORANGE Blink 14.0~14.7 28.0~29.4 56.0~58.8

OVER RED BLINK 14.7 29.4 58.8

3-1-4. Load Level：Display AC Loads (Watts)

LED status DARK GREEN ORANGE RED

SK700
SK1000
SK1500
SK2000
SK3000

0 ~ 35W
0 ~ 50W
0 ~ 75W

0 ~ 100W
0 ~ 150W

35 ~

230W

50 ~

330W

75 ~

495W
100 ~
660W
150 ~
990W

230 ~
525W
330 ~
750W
495 ~

1125W

660 ~

1500W

990 ~

2250W

525 ~
672W
750 ~
960W

1125 ~
1450W
1500 ~
1920W
2250 ~
2880W

RED

BLINK

Over

672W

Over

960W

Over

1450W

Over

1920W

Over

2880W

3-1-5. AC Frequency：Selected by “S4” Dip Switch

Frequency S4

50 HZ OFF

60 HZ ON

3-1-6. Status：Display Power & Fault Status

Green LED LED Signal Status

Solid Power OK

Blink (Slow)

Red LED LED Signal Status

Blink (Fast)

Blink (Slow)

Blink

(Intermittently)

Solid OLP

3-1-7. Power Saving Mode: Power Saving Mode is adjustable and

set by the Dip Switches, S1, S2 and S3 on front panel.

Example: With the watt setting at 15W, a 15W↑ load will
bring the inverter to operate normally, a 15W↓ load, the
Power saving mode presents.

- - - - - - -

- - - - - - - - - - - -

- - - - - - -

. . . . . . . .

Power Saving

OVP

UVP

OTP

SK700

DISABLE DISABLE DISABLE OFF OFF OFF

15W 20W 40W ON OFF OFF
30W 40W 80W OFF ON OFF
40W 50W 100W ON ON OFF
56W 60W 120W OFF OFF ON
70W 80W 160W ON OFF ON
84W 90W 180W OFF ON ON

100W 110W 220W ON ON ON

SK1000
SK1500

SK2000

S1 S2 S3

SK3000

3-1-8. AC outlets (available):

1

4

3-2. Rear Panel Operations：

3-2-1. Remote Port:

The SK Series Inverter can be compatible with any of remote
controllers, CR-6, CR-7 or CR-8.
Before using the remote unit, make sure the main switch must
be “ REMOTE”.

3-2-2. Fan Ventilation:

Do not obstruct, allow at least 1 inch for proper air flow.

3-2-3. DC Input Terminals：

Connect to 12V / 24V / 48V battery or the other power
sources.

【＋】is positive,【－】is negative. Reverse polarity
connection

will blow internal fuse and may damage inverter permanently.

DC Input Voltage

Model

Minimum Maximum

12 V 10.5 15.0
24 V 21.0 30.0
48 V 42.0 60.0

3-2-4. Chassis Ground: using # 8 AWG wire to connect vehicle
chassis.

3-3. Protections Features:

Model

12V 15.3 14.2 11.0 10.5 12.5
24V 30.6 28.4 22.0 21.0 25.0
48V 61.2 56.8 44.0 42.0 50.0

Over Voltage Under Voltage INTERIOR HEAT SINK
Shut­down

DC Input (VDC) Over Temperature Protection

Under

Restart

Voltage

Alarm

Shut­down

Restart Shut-

WARNING!
Operation of the inverter without a

proper ground
connection may result in an
electrical safety hazard.

3-4. Installation：

Where to install. The power inverter should be installed in a location
that meets the following requirements：

3-4-1. Dry – Do not allow water to drip or splash on the inverter.
3-4-2. Cool – Ambient air temperature should be between 0℃ and

40℃, the cooler the better.

down

70

deg C

Restart Shut-

down

45

deg C

90

deg C

Restart

60

deg C

3-4-3. Safe – Do not install in a battery compartment or other areas

where flammable fumes may exist, such as fuel storage areas
or engine compartments.

3-4-4. Ventilated – Allow at least one inch of clearance around the

inverter for air flow. Ensure the ventilation openings on the
rear and front of the unit are not obstructed.

3-4-5. Dust – Do not install the Inverter in a dusty environments

where are dust, wood particles or other filings/shavings are
present. Dust can be pulled into the unit when the cooling fan is
operating.

3-4-6. 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 3-5).
Also do not mount the Inverter where it will be exposed to the
gases produced by the battery. These gases are very corrosive
and prolonged exposure also will damage the Inverter.

3-5. Making DC Wiring Connections：

Follow this procedure to connect the battery cables to the DC input
terminals of the Inverter. Your cables should be as short as possible
(Ideally, less than 6 feet / 1.8 meters ) enough to handle the required
current in accordance with the electrical codes or regulations
application. Cables are not an adequate gauge (too narrow) or too
long will decrease the inverter performances such as poor surge
capability and low input voltage warnings frequently and shutdowns.
UVP warning presents due to DC voltage drop across the cables from
the inverter to the batteries.

The longer or narrower the cables, the greater the voltage drop.
Increasing your DC cable size will help improve the situation.
Following cable recommendations for the best performance of inverter.

(Apply both 120V and 230V versions )

Model No Wire AWG Inline Fuse
SK700-112 / 212
SK700-124 / 224
SK700-148 / 248

SK1000-112 / 212
SK1000-124 / 224
SK1000-148 / 248
SK1500-112 / 212
SK1500-124 / 224
SK1500-148 / 248
SK2000-112 / 212
SK2000-124 / 224
SK2000-148 / 248
SK3000-112 / 212
SK3000-124 / 224
SK3000-148 / 248

# 4
# 6
# 8
# 2
# 4
# 6
# 2
# 4
# 6
# 2/0
# 1/0
# 2
# 4/0
# 2/0
# 1/0

100 A

50 A
30 A

150 A

80 A

40 A
200 A
100 A

50 A
250 A
125 A

70 A
400 A
200 A
100 A

3-5-1. Connect the cables to the power input terminals on the rear

panel of the inverter. The red terminal is positive (+) and black
terminal is negative (-). Insert the cables into the terminals
and tighten screw to clamp the wires securely.

Also, use only high quality copper wire and keep cable length short, a
maximum of 3 - 6 feet.

WARNING!
Make sure all the DC connections are

tight (torque to 9 – 10 ft-lbs, 11.7 – 13
Nm). Loose connections could result
overheat in a potential hazard.

WARNING!
The installation of a fuse must be on

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.

1

8

3-6. AC Safety Grounding：

The AC output ground wire should go to the grounding point for your
loads ( for example, a distribution panel ground bus ).

3-6-1. Neutral Grounding (GFCI’S)：

3-6-1-1. 120V models：The neutral conductor of the AC
output circuit of the Inverter is automatically connected to the
safety ground during inverter operation. In accordance with
the National Electrical Code requirements that separately
derived AC sources (such as inverter and generators) have
their neutral conductors tied to ground in the same way that
the neutral conductor from the utility is tied to ground at the AC
breaker panel. For models configured with a transfer relay,
while AC utility power is presenting and the Inverter is in
bypass mode, this connection (neutral of the Inverter’s AC
output to input safety ground) is not present so that the utility

neutral is only connected to ground at your breaker panel,
as required.

3-6-1-2. 230V models：There is no connection made inverter

interior between either the line or neutral conductor
to the safety ground.

Ground Fault Circuit Interrupters (GFCI)：

Installations in Recreational Vehicles (for North American approvals)
will require GFCI protection of all branch circuit connected to the AC
output of the hardwire terminal equipped Inverter. In addition,
electrical codes require GFCI protection of certain receptacles in
residential installations.

While the pure sine wave output of the Inverter is equivalent to the
waveform provided by utilities, compliance with UL standards requires
us to test and recommend specific GFCI.

Cotek has tested the following GFCI – protected 20A receptacles and
found that they functioned properly when connected to the output of
the Inverter.

3-7. Inverter Operation：

To operate the power inverter, turn the main switch ON. The power
inverter is now ready to deliver AC power to your loads. If there is
several loads use, turn them on separately after the inverter has been
“ON” in order to prevent the OVP present caused by the surge power.

3-7-1. Set the power switch to the “ON” position and the buzzer will

send out “Beep” sounds at the moment the inverter will do self­diagnosis, then the LED’s indicators will also appear various
colors. Finally the buzzer will sound another “Beep” and the
Input Level and Status LED indicators will turn to “Green” color,
the inverter starts working successfully.

3-7-2. Set the power switch to the OFF position, the inverter stops and

all the lights that are On, go Off.

3-7-3. Set power inverter switch to the ON position and turn the test

load On. The inverter should supply power to the load. If
you plan to accurately measure the true output r.m.s. voltage of
inverter, a meter such ad FLUKE 45 BECKMAN 4410 or
TRIPLETT 4200 must be used.

2

4. Troubleshooting guide：

Problems and Symptoms Possible Cause Solutions
“No AC Power Output”

STATUS illuminates the
red LED

a. Blinking fast

b. Blinking slow.

c. Blinking Intermittently.

d. Solid ON. Short circuit or Wiring error.

Over input voltage.
( OVP )

Low input voltage.
( UVP )

Thermal shutdown.
( OTP )

Overload.(OLP)

Check input voltage.
Reduce input voltage.

Recharge battery.
Check connections
and cable.

Improve ventilation.

Make sure ventilation
openings in inverter
are not obstructed.
Reduce ambient
temperature.

Check AC wiring for
short circuit.
Reduce load.

WARNING!

Do not open or disassemble the Inverter.
Attempting to service the unit yourself may
result in a risk of electrical shock or fire.

5. Maintenance：

Very little maintenance is required to keep your inverter operating properly.
You should clean the exterior of the unit periodically with a damp cloth to
prevent accumulation of dust and dirt.
At the same time, tighten the screws on the DC input terminals.

6. Warranty：

We warrant this product against defects in materials and workmanship for a
period of 12 months from the date of purchase and will repair or replace any
defective Power Inverter when directly returned, postage paid, to us.
This warranty will be considered void if the unit has suffered any obvious
physical damage or alteration either internally or externally and does not
cover damage arising from improper use such as plugging.
The unit into an unsuitable power sources attempts to operate products with
excessive power consumption requirements, or use in unsuitable

environments. This is the only warranty that the company makes.
No other warranties express or imply including warranties of merchantability
and fitness for a particular purpose. Repair and replacement are your sole

remedies and the company shall not be liable for damages, whether direct,
incidental, special or consequential, even though caused by negligence or
other fault.