The current will be displayed normally only when the 4.5-30V 0-50A dual LED voltmerer is used with 50A 75mV shunt.

DC 4.5-30V 0-50A Dual LED Digital Volt meter :

Description

DC 4.5v-30V 0-50A Dual LED Digital Voltmeter Ammeter Voltage AMP Power Meter
(connect with 50A/75mV shunt)

Product Features:
1.The small size of the two-color dual instrument.Voltage and current can be displayed on the same screen at the same time
2.This instrument test voltage, current?
3.The the instrument test voltage supply range: DC4.5 ~ 30V,The reverse does not burn,
Note: The maximum input voltage can not exceed 30V, otherwise there is the danger of burned
4.The instrument is equipped with five wiring.Convenient access to car / battery car / motorcycle car line,,Used to monitor the battery voltage,,Grasp the battery voltage state,can also be used for other products, the use of Voltage/current measurement.

Wiring Method:
The instrument with five lines:
Thin black line: Header supply ground
The Thin Red Line: Header powered regular (Note, thin red and black line between the voltage can not exceed 30V)
Thick black lines: public test end
Thick red line: measuring the positive voltage input terminal
Yellow lines: current input terminal; header uses of design, the measuring end of the ground and the ground of the power supply side is the same, it is only then measured the back of the device, as shown in the following figure, the wrong will burn (If you only use the voltage function,but without current function, I recommend you the connect the yellow cable with the black one, and this is to prevent interference caused by current meter numbers flashing. So the current will dispaly correctly. But if you need to display the supply and current at the same time, you need to connect them per the three wiring diagram, otherwise the current can't display correctly)

Technical parameters:

0.Supply voltage: 4.5 30V (wide range)
1.Test voltage: DC 4.5 - 30V; minimum resolution: 0.1V
2.Test current range: 50A resolution: 0.1A (requires an external shunt)(connect with 50A/75mV shunt)
3.Operating Current: <60mA
4.Display: 0.28 "LED, red color.
5.Dimensions: 48 × 29 × 21 mm
6.Mounting cutout: 45.5 × 26.5 mm
7.Measurement rate: ? 500mS / times
8.Measurement accuracy: 1% (± 1 words)
9.Extreme working conditions:
9.1.The minimum Operating voltage: +4.5 V
9.2.Maximum working voltage: +30 V
9.3.Operating temperature: -10 to +65
9.4.Operating Humidity: 10 to 80% (non-condensing)
9.5.Working pressure: 80 ~ 106kPa
9.6.Sun exposure: no direct exposure

FL-2 50A 75mV DC current shunt resistor :

1.FL-2 Series Fixed fixed value shunt is used to expand the instrument to measure the current range, the main technical parameters
2.Accuracy level :2-4000A, 0.5
3.Voltage drop: 75mV
4.Rated current: 50A
5.Environmental conditions: -40 ~ +60 ?, the relative temperature ? 95% (35 ° C)
6.Resistance to mechanical force performance: can withstand acceleration for seconds and impact frequency of 80 to 120 beats per minute to 6 hours of transport Britain earthquake
7.Overload performance: 120% of rated current, 2 hours
8.Load heat: temperature rise changes stabilized, rated current of 50A does not exceed 80 ° C; rated current of 50A does not exceed 120 ° C.

Here below is the wiring diagram for your reference:

Package Included:

• 1 x 4.5-30V 0-50A Dual LED Digital Volt meter
  
• 1 x 50A 75mV DC AC current shunt resistor