Power Source; How Power Converters Work; Led Indicator And Shutdown Protection - Schumacher Electric BATTERY EXTENDER BE01256 Owner's Manual

7. 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.

8. HOW POWER CONVERTERS WORK

There are two stages involved in converting 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" waveform is generated by this conversion.

9. LED INDICATOR AND SHUTDOWN PROTECTION

The LED glows GREEN when the switch is on, and under the following conditions:
1. When the power input from the vehicle's battery drops to approximately 10
volts, low battery shutdown occurs and the converter shuts off. The Green and
Red LEDs are on, with a buzzer. Recharge or replace the battery.
2. When the power input from the vehicle's battery exceeds 15 volts, high voltage
overload protection occurs. The Green LED is on, and the buzzer will sound.
Reduce the voltage range to between 12 volts and 14 volts.
3. The continuous load demand from the equipment or device being operated
exceeds the continuous load rating of the converter being used. The output
pulses ON and OFF; the Green LED is on.
Use a higher capacity converter or lower-rated device.
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