For the "normal" USB port, I already have various USB multimeters here that measure the current and voltage flowing through the USB port. With the purchase of my new MacBook Pro, however, another new purchase was necessary: A USB-C multimeter, which also determines these measurement data if you want to measure them at the USB-C port.
When I started my search at the large online department store, I was quite astonished that there was exactly one model there that offered this function. The Satechi USB-C measuring device is the only one with an input and output according to the new USB C 3.1 standard. Meanwhile there is still a identical model from Jokitech , and a Model by Plugable came to that, but a few weeks ago Satechi was still alone in the hallway and for that reason my choice for this test.
Chapter in this post:
Purpose of the USB multimeter
I use the ammeter and voltmeter for the USB port for different purposes. When I test chargers for the MacBook or MacBook Pro, an important consideration is how many watts they charge the MacBook with. I've had devices in the past that managed to get the MacBook to show it was charging, but in practice the charging current was so low that it would have taken two days to charge the 15-inch MacBook Pro. In these cases it is helpful to know exact numbers for the test report.
The current output of power banks is also interesting, as they increasingly have a USB-C output and can potentially charge a MacBook with it.
And last but not least, I can use this meter to check how much power an external USB-C device "draws" from my MacBook when it is connected, because the Satechi meter works bidirectionally and also shows me this information.
The "Specs" of the small USB measuring device are quickly ticked off:
- Measuring range voltage: 4 to 20 volts (display with one decimal place)
- Measuring range current: 50 mA to 9,99 Ampere (display with two decimal places)
- Electrical charge measuring range: 0 to 9999 mAh
- Display: OLED (blue) with approx. 30 x 10 mm
- Dimensions with connector: 64 x 8 x 22 mm
- Connections: USB-C male and female
- bidirectional measurement possible in both directions
- Model: ST-TCPM
Incidentally, you can get support from Satechi via email firstname.lastname@example.org.
Functionality and features of the Satechi USB measuring device
Compared to some other USB measuring devices that I own (but which have the "normal" USB connection), the Satechi device is relatively poor in features. However, the functionality is the same for all USB multimeters: The Satechi USB multimeter is inserted between the end device and the charging cable and then displays the Satechi logo for about 1 second before it switches to the data view.
The display shows the current voltage in volts, the current in amperes and the electrical charge that has “flowed through” so far in milliampere hours (mAh). An arrow on the display also shows the direction in which the current is currently flowing. For example, if you attach an external hard drive to the MacBook, the arrow will point away from the MacBook to the hard drive.
The display of the electrical charge is always zeroed when the device is unplugged. This is in the nature of things, as the USB measuring device also loses its power supply when it is unplugged, but it has a small disadvantage, which I will explain to you in more detail below.
Speaking of precise: Unfortunately, I cannot make any statements about the accuracy of the measurement results displayed by the USB-C multimeter. The values are definitely plausible. Unfortunately, I don't have a direct comparison with a calibrated measuring device, so I can only assume that they are good enough for "home use".
By the way: The measuring device does not display any data if it is only plugged into a charging cable. As long as there is no current (for example to a connected laptop), the display remains black.
Disadvantages and suggestions for improvement
Basically, Satechi has already delivered a good product here. In most cases, the display of current, voltage and electrical charge is sufficient. When checking chargers, however, a display of the power in watts would have been helpful. This can of course also be calculated by multiplying voltage and amperage, but a direct display is more convenient.
The second point of criticism on my part is the readability of the ad. This is usually not an issue indoors, but when you're outside in sunlight or in a very bright work environment, it gets really difficult. A bit more contrast and a backlit display would have been great.
Furthermore, I would have found it practical if the manufacturer had equipped the device with a short USB-C cable. The measurements can be carried out just as well, but due to the size of the device it is not possible to use the second USB-C port on the MacBook Pro. If you use the device on the right side of the MacBook Pro for this reason, you have the problem that the display is upside down. Both cases could have been solved easily with a short connecting cable. For this reason, I will get a USB-C extension to compensate for this disadvantage.
The last point of criticism from me is the lack of an external power supply. Although it is easier to supply the device with power directly via the already existing USB-C connection, this has a major disadvantage when measuring the electrical charge of power banks: Do I connect the power bank to a USB consumer or USB load resistor in order to To measure the capacity of the power bank, the USB multimeter records the mAh, but the value is lost immediately when the power bank is empty and no longer supplies power.
For a higher measurement accuracy and the preservation of the data, a connection to an external power source - such as via a Micro-USB Cable - very helpful. But honestly, most USB multimeters don't have this. I only know that PortaPow Premiumthat has its own rechargeable battery so as not to falsify the measurement data. But unfortunately this only runs via USB-A and not USB-C.
Conclusion: a usable USB multimeter for the type C connection
Despite the above criticisms, I can Satechi USB multimeter recommend. The display is legible indoors and the values appear to be correct. There are only minor features of the features that I would have liked to improve. But currently the selection of USB-C voltmeters is so small that one can be satisfied.
If you want to save a bit, you can do that too Take a look at the Jokitech USB-C measuring device. It costs a few euros less and looks very, very similar. The indications on the display are almost 1: 1 the same. I haven't tried it, but maybe someone who has tried it can leave a comment here.
Jens has been running the blog since 2012. He acts as Sir Apfelot for his readers and helps them with technical problems. In his spare time he rides electric unicycles, takes photos (preferably with the iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions to current bugs.
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