Schumacher Electric PI-750 User manual

00-99-000348/0308
OWNER'S MANUAL
750 Watt DC to AC Power Inverter
Converts 12V DC Battery Power
into 110-120V AC Home Power
– SAVE THESE INSTRUCTIONS –
Use Schumacher inverters to convert low-voltage, direct-current
(DC) to 110-volt alternating household current (AC). Two sources
of power are:
Standard 12-volt automobile and marine batteries
Portable high-power, 12-volt sources like those found
in jump starter and DC power sources.
MODEL PI-750

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The advanced surge capacity of the PI-750 power invert-
er gives it the means to start most electrical appliances
including: Color televisions, TV/VCR combinations,
microwaves, refrigeration units, small air conditioners.
In addition, the PI-750 power inverter consumes less bat-
tery power, therefore runs for a longer time because it
is a state-of-the-art inverter. It runs cooler and is highly
efcient.
Before Using PI-750
When you turn on an appliance or a tool that runs on a
motor, the appliance basically goes through two stages:
1. Start up - requiring an initial surge of power (commonly
known as the "starting load" or "peak load").
2. Continuous operation - power consumption drops
(commonly known as the "continuous load").
Before using your power inverter, you need to calculate
these loads, i.e.:
1. Starting load (at start up).
2. Continuous load (on continuous operation).
The formula for power consumption (measured in either
WATTS (wattage) or AMPS (amperes) is: AMPS x
110 (AC voltage) = WATTS. The wattage (WATTS) or
amperes (AMPS) can normally be found stamped or
printed on most appliances and equipment, or in the
user's manual. Otherwise, contact the manufacturer to
nd out whether the device you are using is compatible
with a modied sine wave.

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To calculate the starting load: Starting Load = 2 x
WATTS. In general, the start up load of the appliance
or power tool determines whether your inverter has the
capability to power it.
To calculate the continuous load (same as wattage in the
above formula): Continuous load = AMPS x 110
(AC voltage)
Attention: Always run a test to establish whether the
inverter will operate a particular piece of equipment or
appliance.
In the event of a power overload, the inverter is designed
to automatically shut down. This safety feature prevents
damaging the inverter while testing appliances and equip-
ment within the 750-watt range.
If an appliance will not operate properly when rst con-
nected to the inverter, turn the inverter rocker switch ON
(I), OFF (0), and ON (I) again in quick succession. If this
procedure is not successful, it is likely that the PI-750
inverter does not have the required capacity to operate
the appliance in question.
Important: Make sure you connect your inverter to a
12-volt power supply only.
Do not attempt to connect the inverter to any other power
source, including any AC power source.
Do not try extending or otherwise changing the 12-volt
power cord attached to your inverter.

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Incorrect operation of your inverter may result in damage
and personal injury. Electrical current on a 110-volt circuit
can be very dangerous.
Your inverter features include:
A. ON/OFF Rocker Switch
B. LED Indicator Light. (Green = Power ON, Red =
Overload)
C. Two Standard Electrical 110V AC Outlets
D. 12-Volt Power Cord
E. High-Speed Cooling Fan
F. 2 50-Amp Fuses
How To Connect your PI-750 Inverter
Make sure the ON/OFF rocker switch is in the OFF (0)
position. Push the 12-volt power plug rmly into the
outlet. Switch the inverter rocker switch to the ON (I)
position. The LED indicator light should glow GREEN
verifying the inverter is receiving power. Turn the inverter
rocker switch to the OFF (0) position. (The GREEN LED
power indicator light may ash briey and/or the internal
speaker may make a brief "beep." This is normal). Make
sure that the appliance to be operated is turned OFF.
Plug the appliance into one of the two AC outlets. Turn
the inverter rocker switch to the ON (I) position. Turn the
appliance on.
Attention: The internal speaker may also make a brief
"beep" when the inverter is being connected to or discon-
nected from the 12-volt power source.
You can use an extension cord from the inverter to the
appliance without signicantly decreasing the power being

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generated by the inverter. For best operating results, the
extension cord should be no longer than 50 feet.
The LED Indicator briey ashing when you rst turn the
inverter ON, is a sign if that there is a short circuit within
the power supply. Turn the inverter OFF. Turn the inverter
ON again. If this does not remedy the problem try using a
different 12-volt power source.
Using the Inverter to Operate a TV or Audio Appliance
The inverter is shielded and ltered to minimize signal
interference. Despite this, some interference may occur
with your television picture, especially with weak signals.
Below are some suggestions to try and improve reception.
Make sure the television antenna produces a clear signal
under normal operating conditions (i.e., at home plugged
into a standard 110 AC wall outlet). Also, ensure that the
antenna cable is adequately shielded and of good quality.
Try altering the positions of the inverter, antenna cables,
and television power cord. Add an extension cord from
the inverter to the TV so as to isolate its power cord and
antenna cables from the 12-volt power source. Try coil-
ing the television power cord and the input cables running
from the 12-volt power source to the inverter. Afx one or
several "Ferrite Data Line Filters" to the television power
cord. Ferrite Data Line Filters can be purchased at most
electronic supply stores including Radio Shack - Part
Number 273-105. Try grounding the inverter with an 18
AWG (minimum) wire, using as short a length as possible.

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Attention: You may hear a "buzzing" sound being emit-
ted from inexpensive sound systems when operated with
the inverter. This is due to ineffective lters in the sound
system. Unfortunately, this problem can only be resolved
by purchasing a sound system with a higher quality
power supply.
If the Inverter Fuse Blows?
Your PI-750 power inverter is tted with (2) 50-AMP
spade type fuses, which should not have to be replaced
under normal operating circumstances. A blown fuse is
usually caused by reverse polarity or a short circuit within
the appliance or equipment being operated.
If the fuse does blow:
1. Disconnect the appliance or equipment immediately.
2. Find the source of the problem, and repair it.
3. Install the new fuses (supplied with your power inverter.)
The fuse compartment can be found inside the back plate
of the inverter.
Attention: Do not install a fuse higher than 50-AMPs,
as this may damage the inverter. Make sure to correct the
cause of the blown fuse before using the PI-750 again.
NOTE:If necessary, two, 40-amp spade type fuses can
be installed if 50-amp fuses are not available.

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Power Source
Your average automobile or marine battery will provide an
ample power supply to the inverter for 30 to 45 minutes
even when the engine is off. The actual length of time the
inverter will function depends on:
1. Age and condition of the battery.
2. Power demand being placed by the equipment being
operated with the inverter.
If you decide to use the inverter while the engine is off,
we recommend: Turn OFF the device plugged into the
inverter before starting the engine. Start the engine
every hour and let it run for approximately 10 minutes to
recharge the battery.
Attention: Although it is not necessary to disconnect
the inverter when turning over the engine, it may briey
cease to operate as the battery voltage decreases. When
the inverter is not supplying power, it draws a very low
amperage from the battery. The inverter may be left con-
nected to the battery for up to three hours. It is recom-
mended that the inverter always be disconnected when
not in use.
Safety Features
The LED Indicator light will turn from GREEN to RED and
the inverter will automatically turn itself off when:
1. The power input from the battery drops to approximately
10 volts. (When the power input drops to approximately
10.5 volts, an alarm will sound for an extended period).

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2. The power input from the battery exceeds 15 volts.
3. The continuous load demand from the equipment or
appliance being operated exceeds 750 watts.
4. The case temperature exceeds 145 ºF.
Attention: The PI-750 is tted with a cooling fan that
runs as needed while the inverter is operating. If the cool-
ing fan is unable to maintain a cool enough temperature
for safe operation, the inverter will automatically shut
down. If the inverter automatically shuts down or a con-
tinuous audible alarm is heard:
1. Turn the inverter rocker switch to OFF (O).
2. Determine the source of the problem, and resolve it
before continuing to use the inverter.
Important Safety Measures
For the most effective use, place the power inverter on a
at surface.
Keep the inverter dry.
DO NOT allow it to come into contact with rain or mois-
ture.
DO NOT operate the inverter if you, the inverter, the device
being operated or any other surfaces that may come in
contact with any power source are wet. Water and many
other liquids can conduct electricity, which may lead to
serious injury or death.
Do not place the inverter on or near heating vents, radia-
tors or other sources of heat.

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Do not place the inverter in direct sunlight. The ideal air
temperature for operation is between 50º and 80ºF.
Keep the inverter well ventilated in order to properly dis-
perse heat generated while it is in use.
While in use, make sure there are several inches of clear-
ance around the top and sides of the inverter.
Do not use the inverter near inammable materials.
Do not place the inverter in areas such as battery com-
partments where fumes or gases may accumulate.
How Do Power Inverters Work?
There are two stages involved in transforming 12-volt DC
(or battery) power into 110V AC (household voltage):
STAGE 1: The PI-750 power inverter uses a DC to DC
transformer to increase the 12-volt DC input voltage from
the power source to 145-volts DC.
STAGE 2: The inverter then converts the 145-volts DC
into 110-volts AC (household voltage) using advanced
MOSFET transistors in a full bridge conguration. A "modi-
ed sine wave" waveform is generated by this conversion.
For Your Safety: Precautions to keep in mind before
and while using your power inverter:
Only connect the power inverter to a 12-volt battery.
Only connect the power inverter to a 12-volt battery with
the supplied 12-volt power cords. Make sure the cord
connections to the inverter are tight.
Do not modify the power cord or plug in any way.

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Make sure the inverter is not close to any potential source
of inammable fumes or gases before connecting the
inverter to the power source.
Make sure the power consumption of the appliance or
equipment you want to operate is compatible with the
capacity of the inverter, i.e. does not exceed 750 watts.
If you are using the power inverter to operate a battery
charger, monitor the temperature of the battery charger for
about 10 minutes. If the battery charger becomes abnor-
mally warm, disconnect it from the inverter immediately.
Use only (2) 50-amp or (2) 40-amp spade type fuses.
If you are powering the inverter with an automobile or ma-
rine battery, start the engine every 30 to 45 minutes and
let it run for about 10 minutes to recharge the battery.
If you hear a continuous alarm or automatic shut down, turn
the inverter OFF immediately. Do not restart the inverter
until the source of the problem has been identied and
corrected.
Disconnect the inverter when not in use, in order to avoid
battery drain.

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Troubleshooting
PROBLEM: Low or No Output Voltage
Reason/Solution
1. Poor contact at terminals.
Unhook and rehook the 12-volt connections.
2. Using incorrect type of voltmeter to test output
voltage.
Use a true RMS reading meter.
PROBLEM: Red LED On
Reason/Solution
1. Battery voltage below 11 volts.
Recharge or replace battery.
2. Equipment being operated is drawing too much
power.
Use a higher capacity inverter or do not use this
equipment.
3. Inverter is too hot (thermal shut down mode).
Allow inverter to cool. Check for adequate ventilation.
Reduce the load on the inverter to rated continuous
power output.
4. Unit may be defective.
See warranty and call customer service.

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PROBLEM: Low Battery Alarm On All The Time
Reason/Solution
1. Input voltage below 11 volts.
Recharge or replace battery to maintain adequate power
input.
2. Poor or weak battery condition.
Recharge or replace battery.
3. Inadequate power being delivered to the inverter
or excessive voltage drop.
Check condition of cigarette lighter socket. Clean or
replace if necessary.
PROBLEM: TV Does Not Work
Reason/Solution
1. TV does not turn on.
Try turning the inverter ON, then OFF, then ON again.
Contact TV manufacture for start up surge and/or if the
TV is compatible with a modied sine wave. An inverter
producing a larger power output may be required.

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SPECIFICATIONS:
Maximum Continuous Power ............................. 750 Watts
Surge Capability (Peak Power) ........................ 1500 Watts
No Load Current Draw ............................................. < 0.4A
Wave form .......................................... Modied Sine Wave
Input Voltage Range.......................................... 10-15 VDC
AC outlets................................ 110V AC 3 prong grounded
Fuse....................... (2) 50-amp or (2) 40 amp (spade type)
Dimensions ...................................... 8.5” L x 4" W x 2.2" H
Weight ........................................................approx. 3.5 lbs.
Limited Warranty
Schumacher Electric Corporation warrants your inverter
to be free from defects in material and workmanship,
excepting abuse or misuse, for a period of two years
from the date of sale to the original user or consumer
purchaser. If your inverter malfunctions or fails within the
24-month warranty period because of a defect in mate-
rial or workmanship, we will repair it without charge or
replace it.
This warranty is in lieu of all other express warranties.
The duration of any implied warranty, including but not
limited to, any implied warranty of merchantability or fit-
ness for a particular purpose made in respect to your
unit, is limited to the period of the express warranty set
forth above.

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For warranty service, return your inverter, as well as
proof of purchase to the factory or a designated agent:
Schumacher Electric Corporation,
Warranty Service Department
1025 Thompson, Hoopeston, IL 60942
Phone: [phone] (Hours: 7 a.m. - 4:30 p.m. CST)
You will be responsible for all insurance and freight or
other transportation charges to the factory or point of
repair. We will return your inverter freight prepaid if repair
is covered under warranty. Your inverter should be prop-
erly packed to avoid damage in transit since we will not
be responsible for any such damage.
In no event shall Schumacher Electric Corporation be liable
for consequential damages. Some states do not allow limita-
tions on the length of the implied warranty or the exclusion
or limitations of incidental or consequential damages, so the
above limitations or exclusions may not apply to you. This
warranty gives you specific legal rights and you may also
have other rights which may vary from state to state.
Schumacher Website: www.batterychargers.com