Our Thanks To You
Thank you for purchasing the Cobra® CPI 400
inverter. Properly used, this Cobra® product will
give you many years of reliable service.
Operating Instructions
How Your Cobra® Power Inverter Works
The Cobra® Power Inverter is an electronic product
that has been designed and built to take low voltage
DC (Direct Current) power from your automobile by
simply connecting the power inverter to the cigarette
lighter socket (or connecting directly to other low voltage
power supplies) and CONVERT it to standard 115 volt AC
(Alternating Current) power like the current you have in
your home. This conversion process thereby allows you to
use many of your household appliances and electronic
products in automobiles, RVs, boats, tractors, trucks and
virtually anywhere else.
Customer Assistance
Customer Assistance
Should you encounter any problems with this product,
or not understand its many features, please refer to this
owner’s manual. If you require further assistance after
reading this manual, Cobra® Electronics offers the
following customer assistance services:
For Assistance In the U.S.A.
Automated Help Desk English only.
24 hours a day, 7 days a week 773-889-3087 (phone).
Customer Assistance Operators English and Spanish.
8:00 a.m. to 6:00 p.m. CT, Monday through Friday
(except holidays) 773-889-3087 (phone).
Questions English and Spanish.
Faxes can be received at 773-622-2269 (fax).
Technical Assistance English only. (on-line: Frequently Asked Questions).
English and Spanish. (e-mail).
For Assistance Outside the U.S.A.
Contact Your Local Dealer
© 2003 Cobra
CPI 400
Nothing Comes Close To A Cobra™
Printed in China
Part No. 480-057-P
A1 English
Electronics Corporation
6500 West Cortland Street
Chicago, Illinois 60707 USA
Controls /Indicators
and Product Features
• Two AC Receptacles
• Automatic Thermal
Our Thanks to You . . . . . . . . . . . . . . . . . . A1
Customer Assistance . . . . . . . . . . . . . . . . A1
Controls and Indicators . . . . . . . . . . . . . . A2
Product Features . . . . . . . . . . . . . . . . . . . A2
Important Safety Information . . . . . . . . . . . 1
Quick Evaluation Before Installation . . . . . . .4
• Reverse Polarity Protection
• Low Battery Alarm
• Low Battery Shutdown
Protection &
Power Indicators
Power Switch
AC Outlets
Table of Contents
Installation Requirements . . . . . . . . . . . . . .6
Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Connecting Cables . . . . . . . . . . . . . . . . . . . 8
Power Consumption . . . . . . . . . . . . . . . . .10
Turning Your Inverter On or Off . . . . . . . . 11
Power and Protection Indicators . . . . . . . 12
Operating Limits . . . . . . . . . . . . . . . . . . . . 13
Troubleshooting Guide . . . . . . . . . . . . . . . 14
Specifications . . . . . . . . . . . . . . . . . . . . . . 15
Cooling Fan
Positive Battery
Cable Terminal
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Negative Battery
Cable Terminal
A2 English
Customer Assistance
Maintenance . . . . . . . . . . . . . . . . . . . . . . . .17
Product Service . . . . . . . . . . . . . . . . . . . . 17
Accessories and Order Form . . . . . . . . . . 18
A3 English
Important Safety
Important Safety Information
Before installing and using your Cobra® Power Inverter,
please read these general precautions and warnings.
Caution and Warning Statements
To make the most of this inverter, it must be installed and
used properly. Please read the installation and operating
instructions carefully before installing and using it. Special
attention must be paid to the CAUTION and WARNING
statements in the manual.
CAUTION Statements specify conditions which
could cause damage to the unit or other equipment.
WARNING Statements identify conditions that
could result in personal injury or loss of life.
General Precautions
1. Never install the inverter in a boat’s engine compartment
where gas and battery fumes are present.
2. Do not operate the inverter if it has been
dropped or damaged in any way.
3. Do not open the inverter; it contains no userserviceable parts. Attempting to service unit
could cause electrical shock.
NOTE Internal components remain
charged after all power is disconnected.
4. Do not expose the inverter to rain, snow,
bilge water or spray.
5. Do not obstruct the ventilation openings.
6. Do not install the inverter in zero-clearance
CAUTION This inverter should be used in
negative ground applications only.
Nothing comes close to a Cobra™
Important Safety
Important Safety
Cobra® 400W Output Waveform
WARNING Power inverters contain components
that tend to produce arcs or sparks. To prevent fire
or explosion, do not install the inverter in areas or
compartments containing batteries or flammable
materials or in locations that require ignitionprotected equipment.
WARNING To reduce the risk of fire, do not cover
or obstruct the ventilation openings. Do not install
inverter in zero-clearance compartment.
Some very sensitive electronic equipment may not
operate satisfactory on “square wave” or “modified sine
wave.” The output waveform is referred to as “square
wave” or “modified sine wave.” It is a stepped waveform
designed to have characteristics similar to the sine
wave shape of utility power. A waveform of this nature
is suitable for most AC loads (including linear and
switching power suppliers used in electronic
equipment, transformers and motors).
Warning: Wash Hands After Handling Power Cord
The power cord on this product contains lead, a chemical
known in the state of California to cause birth defects or
other reproductive harm.
Caution: Rechargeable Appliances
Certain chargers for small nickel cadmium batteries can
be damaged if connected to the Cobra® 400W inverter. Two
(2) particular types of equipment are prone to this problem:
1. Small battery-operated appliances
Plug In Directly
such as flashlights, razors, and
night lights that can be plugged
directly into an AC receptacle to
Certain battery chargers for
Dangerous Voltages
battery packs used in hand power
tools. These chargers have a
WARNING label stating that
dangerous voltages are present
at the battery terminals.
This problem does not occur with the vast majority of
battery operated equipment. Most use a separate charger
or transformer that is plugged into the AC receptacle and
produces a low voltage output. If the label on the AC
adapter or charger states that it produces a low voltage
AC or DC output (less than 30 volts), the inverter will
have no problem powering the adapter safely.
Nothing comes close to a Cobra™
Quick Evaluation
Before Installation
Quick Evaluation Before Installation
This section provides you with basic information about
the inverter and how to check its performance before
Be Sure to Have on Hand:
A 12 volt DC power source (such as a vehicle battery).
The power source must provide
Power Supply
between 11 and 15 volts DC and
be able to supply enough current to
run the test load. As a rough guide,
divide the wattage of the test load by
10 to get the current (in amperes)
the power source must deliver.
The provided 2 ft. cigarette lighter cable.
Only use the cables provided with
your inverter. The cigarette lighter
cable is suitable for operating the
inverter at loads up to 150 watts.
Connect by securely inserting the
plug into the cigarette lighter socket.
CAUTION Do not use the cigarette lighter cable
for loads higher than 150 watts. When connecting
loads larger than 150 watts, please connect the
inverter directly to the battery.
Quick Evaluation
Before Installation
To Check Your Inverter’s Performance Before Installation:
1. Turn the inverter Off (see page 11
On/Off Switch to Off
for details). If the power source is
a DC power supply, switch it Off
as well.
2. Connect cables to Power Input
Connect Terminals
Terminals (see page 8 for details).
3. Connect cable to power source
(see page 8 for details).
4. Check to make sure all
Connect Power Source
connections are secure.
5. Turn the inverter On. If the power
source is a DC power supply,
switch it On first.
On/Off Switch to On
6. Plug in the test load.
Connect Test Load
The inverter should supply power
to the load. If the inverter is not
working properly, refer to the
Troubleshooting Guide on page 14
or Power and Protection Indicators
section on page 12.
A test load that can be plugged into the AC receptacle on
the inverter for short term testing at a low power level.
Test Load
Nothing comes close to a Cobra™
Installation Requirements
The inverter must be installed in an area that meets
all of the following requirements:
A. Dry
Do not place in an area where water can drip
or splash on the inverter.
B. Cool
Ambient air temperature should be between 30°F
and 105°F (0°C and 40°C). The cooler the better.
C. Ventilate
Allow at least 1 inch (3 cm) of clearance around the
inverter for proper airflow. Make sure that ventilation
openings on the ends of the unit are not obstructed.
CAUTION To avoid fire, do not cover or obstruct
ventilation openings. Do not install inverter in a zeroclearance compartment. Overheating may result.
CAUTION The inverter must only be connected
to batteries with a nominal output voltage of 12
volts. It will not work with a 6 volt battery, and will
be damaged if it is connected to a 16 volt battery.
WARNING This unit contains components
which can produce arcs or sparks. To prevent
fire or explosion, do not install in compartments
containing a battery or flammable materials,
or in a location which requires ignition
protected equipment.
To Mount Your Inverter:
1. Place the inverter on a flat surface with the mounting
bracket against the mounting surface.
Mounting Brackets
2. Mount to secure surface using mounting hardware
that is corrosion resistant (not included).
Mounting Hardware
The inverter can be mounted horizontally or vertically.
Nothing comes close to a Cobra™
Connecting Cables
Connecting Cables
Power wire and wiring are very important to the
performance of the inverter. Because the inverter has a
low voltage, high current input, low resistance wiring is
essential between the battery and inverter. This is so it
can deliver the maximum amount of energy to the load.
Only use the cables provided with your power inverter.
To Connect the Cables Between the Inverter
and the Battery:
1. Turn the On/Off Switch on the inverter to the Off
position. If the power source is a DC power supply,
switch it Off as well.
On/Off Switch to Off
2. Connect cable to the Power Input Terminals on
right side panel of the inverter. The red terminal is
positive (+) and the black terminal is negative (-).
Insert the ends of the cables onto the terminals
and tighten the screws to clamp the cables safely.
Connect Terminals
Connecting Cables
3. Connect cable to your vehicle’s cigarette lighter socket.
Connect Power Source
NOTE If the inverter is to be used at levels above
150 watts for extended periods of time, a direct
connection to the battery is recommended. Do
not use the cigarette cord for loads higher than
150 watts. Please contact your local dealer or
customer assistance for the proper cord for
direct to battery connections.
CAUTION Reverse polarity connections (positive
to negative) will blow internal fuses in the inverter
and may permanently damage the unit. Such
damage is not covered by the warranty.
CAUTION Remove any jewelry (watch, ring, etc.).
Be careful not to short circuit the battery with any
metallic object (wrench, etc.).
WARNING You may observe a spark when making
the connection because current can flow to charge
the capacitors in the inverter. Do not make this
connection in the presence of flammable fumes.
Explosion or fire may result. Thoroughly ventilate
the battery compartment before making this
Nothing comes close to a Cobra™
Power Consumption
Power Consumption
For each piece of equipment you will be operating from the
inverter, you must determine the battery’s reserve capacity
(how long the battery can deliver a specific amount of
current — in automotive batteries, usually 25 amperes)
or ampere-hour capacity (a measure of how many amperes
a battery can deliver for a specified length of time).
Example – Reserve capacity: a battery with a reserve
capacity of 180 minutes can deliver 25 amperes for
180 minutes before it is completely discharged.
Example – Ampere-hour capacity: a battery with
an ampere-hour capacity of 100 ampere-hours can
deliver 5 amperes for 20 hours before it is completely
To Determine the Battery Ampere-Hour
Capacity You Require:
1. Determine how many watts each piece of equipment
consumes. This can normally be found on the product
label. If only the current draw is given, multiply the
current draw by 115 to get the watt consumption.
2. Estimate the time (in hours) that each piece of equipment
will be running between battery charging cycles.
3. Calculate the total watt-hours of energy consumption
(power x operating time) using the average power
consumption and the total estimated running time
(in hours). Power x Operating Time = Watt-Hours.
100 Watts x 2 hours
= 200 Watt-Hours
TV/VCR (up to 25")
115 Watts x 3 hours
= 345 Watt-Hours
Power On & Off
Turning Your Inverter On or Off
Be sure to have your power inverter properly installed before
attempting to turn the unit On (see “Installation” page 6).
To Turn the Power Inverter On:
1. If a DC power supply is being used as the power
source, switch it On.
2. On the left side panel, switch the On/Off Switch to On.
On/Off Switch to On
The inverter is now ready to deliver AC power to your loads.
If several loads are to be operated by the inverter, turn them
On separately, after the inverter has been turned On. This
will ensure that the inverter does not have to deliver the
starting currents required for all the loads at once.
To Turn the Power Inverter Off:
1. On the left side panel, switch the On/Off Switch to Off.
On/Off Switch to Off
300 Watts x 15 min
= 75 Watt-Hours
4. Divide the watt-hours by ten (10) to determine how many
power supply’s (12 volt) ampere-hours will be consumed.
10 English
Nothing comes close to a Cobra™
Power & Protection
NOTE The On/Off Switch turns the control circuit
in the inverter On and Off. It does not disconnect
power from the inverter.
When the switch is in the Off position, the inverter
draws no current from the battery. When it’s in the
On position, but no power is being supplied to the
load, the inverter draws less than 500 milliamperes
from the battery. This is low current draw. It would
take more than a week to discharge a 100 amperehour battery at this rate depending on the age of
the battery.
Power and Protection Indicators
The Power and Protection Indicators include a green
light, a red light and an alarm.
Green Light
Power On – The green light should remain On steady.
Red Light and/or Alarm
Current Overload – The red light will turn On momentarily,
then the inverter will shutdown. The inverter will continue
to check for appropriate current levels while trying to
restart the load.
Voltage Overload – The red light will blink and the inverter
will shutdown. The inverter will continue to check for
appropriate voltage levels while trying to restart the load.
Voltage Shortage – As a warning that the voltage is
getting low, the internal alarm will sound. When the
voltage is too low, the inverter will shutdown and the red
light will turn On. The inverter will continue to check for
appropriate voltage levels while trying to restart the load.
Temperature Overload – The red light will turn On
momentarily, then the inverter will shutdown. The inverter
will continue to check for appropriate temperature levels
while trying to restart the load.
Operating Limits
Operating Limits
Power Output
The inverter can deliver 400 watts for about 60 minutes.
The inverter must cool for 15 minutes before it can
resume operation at 400 watts. Note: The wattage
rating applies to resistive loads.
The inverter will operate most AC loads within its power
rating. Some induction motors used in freezers, pumps,
and other motor-operated equipment require very high
surge currents to start. The inverter may not be able
to start some of these motors even though their rated
current draw is within the inverter’s limits. The inverter
will normally start single phase induction motors rated
at 1⁄2 HP or less.
Input Voltage
The inverter will operate from input voltage ranging
from 10 volts to 15 volts. Optimum performance will
occur when the voltage is between 12 volts and 14 volts.
If the voltage drops below 10.5V+/-0.3V, an audible low
battery warning will sound. The inverter will shut down if
the input voltage drops below 9.5V+/-0.3V. This protects
the battery from being over-discharged. It will restart when
the input voltage exceeds 12V+/-0.3V.
The inverter will also shut down if the input voltage
exceeds 15.75V+/-0.75V. This protects the inverter
against excessive input voltage. Although the inverter
has protection against over-voltage, it may still be
damaged if the input voltage were to exceed 16 volts.
NOTE A momentary sound of the internal alarm
and/or flash of the red light is normal at start up.
12 English
Nothing comes close to a Cobra™
Troubleshooting Guide
Troubleshooting Guide
Problem/Symptom Possible Causes
Low output voltage Overload
Reduce the load.
No output voltage Low input voltage Recharge battery.
Check connections
and cable.
No output voltage Thermal
Allow inverter
after prolonged use shutdown
to cool off.
Reduce load,
operation input
current required.
Improve ventilation;
Make sure ventilation
openings in the
inverter are not
Reduce ambient
Make sure
No output voltage, High input
the inverter is
“Protect” indicator voltage
connected to
12V battery.
Check regulation
of charging system.
Check load for
No output voltage Short circuit
proper operation.
Replace fuse.
No power to
Blown fuse
Low battery alarm Poor DC wiring
on all the time
Make sure battery
Poor battery
is fully charged.
14 English
Continuous output power (1 hour) . . . . . . . . . . . . 400w
Surge rating (0.1 second) . . . . . . . . . . . . . . . . . . . 800w
Peak efficiency (12V – 1⁄2 load) . . . . . . . . . . . . . . > 88%
Efficiency (full load, 12V) . . . . . . . . . . . . . . . . . . . > 83%
No load current draw . . . . . . . . . . . . . . . . < 0.5A (12.6V)
Output waveform (resistive load) . . . Modified sine wave
Output frequency . . . . . . . . . . . . . . . . . . . . 58HZ – 62HZ
Output voltage . . . . . . . . . . . . . . . . . . . . . . 109V – 120V
Input voltage . . . . . . . . . . . . . . . . . . 10.4VDC – 14.4VDC
Alarm voltage (unload) . . . . . . . . . . . . . . .10.2V – 10.8V
Shutdown voltage (unload) . . . . . . . . . . . . . 9.2V – 9.8V
Operating temperature range . . . . . . . . . . . . 0°C – 40°C
(32°F – 104°F)
Storage temperature range . . . . . . . . . . . . -40°C – 85°C
(-40°F – 185°F)
Protection . . . . . . . . . .Overload, short-circuit, overtemp,
reverse polarity, under/over voltage
All protection is automatically recovered.
To protect the battery, if the unit needs to be restarted
after low voltage protection, the voltage of DC input
should be above 12V.
To extend the life of the fan, it will stop when there is no
load. The speed of the fan increases as the load increases.
The unit is completely insulated in input and output for
added safety.
Nothing comes close to a Cobra™
Limited 1-Year Warranty
Customer Assistance
For Products Purchased in the U.S.A.
Cobra® Electronics Corporation warrants that its Cobra® Power
Inverter, and the component parts thereof, will be free of defects
in workmanship and materials for a period of one (1) year from the
date of first consumer purchase. This warranty may be enforced by
the first consumer purchaser, provided that the product is utilized
within the U.S.A.
Cobra® will, without charge, repair or replace, at its option,
defective Power Inverters, products or component parts upon
delivery to the Cobra® Factory Service department, accompanied
by proof of the date of first consumer purchase, such as a
duplicated copy of a sales receipt.
You must pay any initial shipping charges required to ship the
product for warranty service, but the return charges will be at
Cobra®’s expense, if the product is repaired or replaced under
warranty. This warranty gives you specific legal rights, and you
may also have other rights which may vary from state to state.
Exclusions: This limited warranty does not apply:
1. To any product damaged by accident.
2. In the event of misuse or abuse of the product or
as a result of unauthorized alterations or repairs.
3. If the serial number has been altered, defaced, or removed.
4. If the owner of the product resides outside the U.S.A.
All implied warranties, including warranties of merchantability
and fitness for a particular purpose are limited in duration to the
length of this warranty. Cobra® shall not be liable for any incidental,
consequential or other damages; including, without limitation, to
damages resulting from loss of use or cost of installation.
Some states do not allow limitations on how long an implied
warranty lasts and/or do not allow the exclusion or limitation
of incidental or consequential damages, so the above limitations
may not apply to you.
For products purchased outside the U.S.A.
Please contact your local dealer for warranty information.
Maintenance and
Product Service
Very little maintenance is required to keep the inverter operating
properly. The exterior of the unit should be cleaned periodically
with a damp cloth to prevent accumulation of dust and dirt. At the
same time, tighten the screws on the DC input terminals. Be sure
vents and fans are free of dust or debris.
Product Service
If you have any questions about operation or installing your new
Cobra® product, or if you are missing parts…
Please call Cobra® first!
See customer assistance on page A1.
If your product should require factory service, please call Cobra®
first before sending your power inverter. This will ensure the
fastest turn-around time on your repair. You may be asked to
send your power inverter to the Cobra® factory.
It will be necessary to furnish the following to have the product
serviced and returned.
1. For Warranty Repair include some form of proof-of-purchase,
such as a mechanical reproduction or carbon copy of a sales
receipt. If you send the original receipt, it cannot be returned;
2. Send the entire product.
3. Enclose a description of what is happening with the power
inverter. Include a typed or clearly printed name and address
of where the power inverter is to be returned.
4. Pack power inverter securely to prevent damage in transit.
If possible, use the original packing material.
5. Ship prepaid and insured by way of a traceable carrier
such as United Parcel Service (UPS) or First Class Mail to
avoid loss in transit to:
Cobra Factory Service, Cobra Electronics Corporation,
6500 West Cortland Street, Chicago, Illinois 60707 USA.
6. If the power inverter is in warranty, upon receipt of your power
inverter, it will either be repaired or exchanged depending on
the model. Please allow approximately 3 – 4 weeks before
contacting Cobra® for status. If the power inverter is out of
warranty, a letter will automatically be sent informing you of
the repair charge or replacement charge.
If you have any questions, please call 773-889-3087 for assistance.
16 English
Nothing comes close to a Cobra™
Customer Assistance
Accessories and
Order Form
Address (No P.O. Boxes)
Credit Card Number
Type: ❒ Visa ❒ Mastercard ❒ Discover
Exp. Date
Customer Signature
Item #
U.S. Cost Each
Amount Shipping/Handling*
Tax Table
$10.00 or less . . . . . $3.00
Ohio, Wisconsin add 5%
Indiana, Michigan add 6%
California add 7.25%
Illinois add 8.75%
$10.01-$25.00 . . . . . $5.50
$25.01-$50.00 . . . . . $7.50
$50.01-$90.00 . . . . $10.50
$90.01-$130.00 . . . $13.50
$130.01-$200.00 . . $16.50
$200.01 plus . . . . . 10% of
The Cobra®
line of quality
products includes:
CB Radios
microTALK® Radios
Radar/Laser Detectors
Safety Alert Traffic
Warning Systems
U.S. Subtotal
(Tax if Applicable)
*For AK, HI and PR add additional $26.95 for FedEx Next Day
or $10.95 for FedEx 2nd Day. Excludes weekend and holiday
Please allow 2-3 weeks for delivery in the U.S. Prices subject
to change without notice.
Optional Accessories
You can find quality Cobra products and accessories
at your local Cobra® dealer, or in the U.S.A., you can
order directly from Cobra®.
Ordering From U.S.A.
Call 773-889-3087 for pricing or visit
GPS (Global
Positioning System)
For credit card orders, complete and return this
order form to fax number 773-622-2269.
Or call 773-889-3087 (Press 1 from the main menu)
8:00 a.m. to 6:00 p.m. CT, Monday through Friday.
HighGear™ Accessories
Make check or money order payable to:
Cobra Electronics, Attn: Accessories Dept.
6500 West Cortland Street, Chicago, IL 60707 USA
18 English
To order online, please visit our website:
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