LCD screen can display various data clearly and accurately
Six kinds of real-time display mode, the voltage, current, power, the capacity of a single charge, total charge capacity, the charging time.
Full charge off automatically, to avoid overcharging
Ultra-low current-sense resistor effectively reduce the pressure drop
Overvoltage protection and alarm (Max 5.7V)
Overcurrent protection (Max.3A)
Operating voltage range: 4.5 - 5.7V DC
Operating current range: 0 - 3A
Voltage detection accuracy: + / -0.5%, resolution: 0.01V
Current detection accuracy: + / -1%, resolution: 0.01A
Sense resistor: 10mOhm
Static power consumption: 20mA
Dimensions: 43x25x11mm
I found this unit on Ebay at a dealer called 2012moon816
How does it look
The device included a manual that explains how to use all the functions.
The device is two circuit board with screws between. To make a mostly closed box some clear heatshrink is used around it.
The heatshrink does not close the inside completely around the connectors.
From the side it can be seen that the display is soldered over the components. The button to select display is also visible.
Somewhere inside there is a buzzer.
The different displays.
Measurements
The device needs 4.5 volt before the values are shown correctly.
The watt display is not U*I, but slightly below, this may be due to rounding. Also be aware that the voltage is somewhere between Vin and Vout, i.e. the power is neither input or output power, but something in between.
This device can disconnect its output!
Display: Volt, current, watt, mAh, Total mAh, time
The button is used to step between values
When load is removed for 10 seconds it will beep a couple of times and show a flashing "End" on the display.
After showing "End", the mAh and time will be start from zero, next time current is drawn, until then they will keep the old value.
A blue led shows when power is connected and output is active.
The buzzer sounds when power is connected, when load is applied, when load is removed and when voltage is to high or low.
When input voltage is above 5.7 volt the output will be turned off.
A long press on the button will activate setting of the end timer, i.e. how long the current has to be zero before "End" is shown, but this does not work, it is always 10 seconds or off.
Own current consumption is 14mA
Voltage display is within 0.02 volt in the 4.5 to 6.0 volt range.
Current display is within 0.02 ampere in the 0 to 2.0 ampere range.
USB data works fine.
Internal resistance is about 0.20ohm including connection resistance.
All capacity displays are zeroed when power is disconnected
M1: 54,0°C, M2: 52,1°C, HS1: 73,3°C
Both the device and the connector get hot.
M1: 52,5°C, M2: 51,9°C, M3: 45,7°C, HS1: 70,9°C
The transistor to turn output on/off gets rather hot.
Conclusion
This device has some interesting function with mAh and disconnect of output, but 3A is to high a rating for it, the meter will show wrong values.
The voltage range is fairly limited, down to 3.5 volt would have been much better. The software bug with the "end timer" is not a big deal, but it is bad quality control.
The device is accetable and the mAh can be useful, but only if you stay above 4.5 volt and below 2.0A.
I have a collection of these usb power meters and never saw this one. Seems very well made. Somehow many of these units struggle to compete with the very famous and inexpensive “charge doctor”.
For any of you considering a serious USB and DC power meter I recommend the portapow premium power monitor, it does not come cheap at $40 but the volt and amp measures are on par with a $250 fluke. It is even accurate up to the thousandths unit. Can also measure in DC in/out for voltage, current, power, capacity and time, altogether.
HKJ if you could somehow make them send you one for review and testing, it would be phenomenal. This device is truly amazing, but not many people know it.
Good to hear!! I look forward to your review, should be really interesting.
I have tested this meter with a lab power supply (in a cellphone repair center) and my readings were consistent with less than 0.2% variation within USB parameters, certainly not the right method for testing, but it’s worth something… and sorry for the thread jacking :bigsmile:
Because it is running on a battery it has a stable supply voltage, this ought to make it much easier to get precise measurements. But how much resistance does it have, with a cable and a extra connector it starts with a disadvantage. I am very curious how good it is.
