Power Source; How Power Converters Work; Led Display - Schumacher Electric PID-500-USB Owner's Manual

POWER SOURCE

Your average automobile or marine battery at full charge will provide an ample
power supply to the converter for approximately 3 hours when the engine is
off. The actual length of time the converter will function depends on the age
and condition of the battery and the power demand being placed by the device
being operated with the converter.
If you decide to use the converter while the engine is off, we recommend
you turn OFF the device plugged into the converter and disconnect the
converter's plug from the 12 volt accessory outlet before starting the engine.
To maintain battery power, start the engine every 2 to 3 hours and let it run for
approximately 10 minutes to recharge the battery.
Although it is not necessary to disconnect the converter when turning over
the engine, it may briefly cease to operate as the battery voltage decreases.
While the converter draws very low amperage when not in use, it should be
unplugged to avoid battery drain.

HOW POWER CONVERTERS WORK

There are two stages involved in transforming 12 volt DC (battery) power into
120 volt AC (household voltage):
STAGE 1: The power converter uses a DC to DC transformer to increase the
12 volt DC input voltage from the power source to 145 volt DC.
STAGE 2: The converter then converts the 145 volt DC into 120 volts AC
(household voltage) using advanced MOSFET transistors in a full bridge
configuration. A modified sine wave is generated by this conversion.

LED DISPLAY

The LED display identifies the current status of the converter.
VOLTAGE IN: The voltage of the vehicle's battery, Portable Power jump
starter or DC power source.
VOLTAGE OUT: The voltage supplied to the device through the AC receptacle.
POWER OUT: The power or wattage supplied to the device plugged into the
converter.
An audio alarm will sound when any of the following codes display. To stop the
alarm, press the ON/OFF switch:
 – The converter is not functional.
 – The vehicle's battery voltage is more than 15.5 volts. The converter will
automatically restart after the voltage drops below 15.0 volts.
 – The continuous load demand from the device exceeds the converter's
wattage output.
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