Dc 4.5-40v to 5v 2a USB charger dc-dc step-down buck converter voltmeter

DC-DC 4.5-40V To 5V 2A USB Charger Step down Converter Voltmeter Module is connected to power, the voltage can be detected in real time.When you need the phone, IPAD, MP3 and other digital products charge, click the "Output Enable" button,then USB power indicator lights, USB output voltage 5.0V.When you need to turn off the voltmeter, click the "Low Power" button, then enter the ultra-low-power standby mode, USB output corresponding shutdown. Wide input voltage, for car / battery car / motorcycle used for monitoring battery voltage; measure the voltage needed for a variety of occasions. The output current capability 5.0V/2A, enough to meet a variety of USB devices, voltage is very stable. Note: This module default D + D- short, most of the cell phone charger is compatible, and set aside a variety of mobile phones identification resistor installation location, if you need to add the identification resistor, please connect D + D- wires cut,then added. Specifications and Features : Input voltage: DC 4.5 ~ 40V. Output voltage: 5V (when the input voltage is between 6.5V ~ 40V). Output current: 2A. The voltmeter has automatic calibration function. With reverse connection protection. With overheat protection and short circuit protection. High efficiency and low ripple. With USB power indicator light. Application: can be used on car, electric bike, motorcycle for voltage measurement and to charge phone, iPad, Mp3 etc. Dimensions : 61 x 11 x 13 (LxWxH) mm. Voltmeter calibration method: Step 1: Press the "Output Enable" button more than 2 seconds, release, voltmeter flashes, this time into the voltage regulation mode. Step 2: press the "Output Enable" button (normal speed), the voltage value is adding up a unit; Press the "Low Power" button, minus a unit; Due to a unit is less than 0.1V, the minimum voltage display to 0.1V, so you need to continuously press 1-5 times to see the voltmeter change 0.1V, how many times voltmeter change 0.1V by pressing the button, depending on the current display voltage, the higher the voltage, the fewer the number of press. Step 3: press the "Output Enable" button more than 2 seconds, release, to exit the voltage calibration mode.Data is not lost after power failure.