Xtar VI01 USB Current/voltage detector

DSC_5080 DSC_5078

DSC_5082

Xtar has made many flashlights and good chargers, this is a new type of product from them. It is a current and voltage meter to use in a usb connection.

DSC_5074 DSC_5076

I got the device in a cardboard/plastic package. It was very easy to open, the cardboard could slide out. The only contents in the package is the device, no usb cable or instruction sheet and it is not needed.

DSC_5079 DSC_5081

There is an usb connector in each end, one male, one female.

DSC_5132

One of the usb connections has a loose cover. I like having a cover over the usb connector, but I do not like loose parts.

DSC_5091

Here it is plugged into a laptop and connected to my phone. The display will show 3 digits and a letter, A for ampere and U for volt. The decimal place is always fixed giving the display a resolution of 0.01 volt and 0.01 ampere.

DSC_5122 DSC_5121

Another test with my laptop, this time with two different cables.
When using the two wire cable the phone will only charge with low current. Using the 4 wire cable (with data), the phone can charge at much higher current.

DSC_5126 DSC_5127

Some other tests it can be used for.



Measurements

DSC_5130

To measure I needed some connection with very low resistance. I made two usb connecter with fairly thick wires sticking out.

DSC_5131

First I measured the two when connected together, the result was 0.03 ohm or 30mOhm, for the wires and connection between the two.
Because I do not know how this is distributed, I cannot compensate for it in the voltage measurements. Anyway, these looses will also be present when using it in real situations and usual they will be larger.

DSC_5129

With the device connected.

DSC_5154

The actual setup required two high precision DMM's, one to measure input voltage and one to measure output voltage and a electronic load.
Voltage was measured on the wires sticking out of my test usb connectors, to avoid voltage drops in thin usb wires.

Measurements

About are some of my measurements. In the two red lines I am way outside the rated specifications and the display shows wrong values.

With a few more test I could draw some conclusions:

Temperature

After a short time the measurement resistor in the device gets warm.

Temperature1h

Running 1 hour at 2.5A made it warmer (max. temperature is higher, see scale) and the current readout was still correct.



Conclusion

The device works as expected and can be very useful to check all types of usb devices with.
The voltage readout will be precise at small loads (i.e. below 1A), but at the higher current it will show a slightly low a value. The current readout is always precise.



Notes

The device was supplied by Xtar for a review.