X7 Charging Issues

[Aviator Joe]

I love this tablet, it's brighter than my Dynon Skyview! I am having an issue. My plane has a power outlet that has a Type A and Type C port in it that I planned to use to keep the X7 charged during flight. When I plug the X7 into the type C port with a USB-C to USB-C cable, the charging appears to start, but then stops within a few seconds. I used to run a Samsug tablet in this manner with no problem. I can charge at home with a power supply or a power brick with no problem, port-C or A.

Any ideas?
Thanks!

 

[Cobra]

Do you have the specs for your plane's power port? Here in 2025, there are now several (dozens?) of possible power standards and voltage/current combinations, and not all devices support all charging standards, and not all charging ports support all charging standards. The negotiated power available given what your port can provide and what your tablet can use may be too low for the tablet to effectively utilize.


Other things to try:

• Do you have any other Type-C to Type-C cables you can try? Not all cables are created equal.
• Do you have a cigarette lighter port in your plane? If so, maybe try a good-quality cigarette lighter power adapter (something like this) and see if you get different / better results.

 

[Aviator Joe]

I was suspicious about what it was delivering. I have to look up the specs. I just realized that a high quality C to C cable comes with the X7, so I'll try that as well. Otherwise, I can use my battery pack on long flights. Thank you for the detailed and fast response!

 

[MDreger]

I was under the impression that all USB ports put out ~5 vdc, yet it seems the chart above contradicts that. If a USB port can put out any one of those voltages, how do we know, and will it damage a device that is supposed to only use the ~5vdc?

 

[Cobra]

I was under the impression that all USB ports put out ~5 vdc, yet it seems the chart above contradicts that. If a USB port can put out any one of those voltages, how do we know, and will it damage a device that is supposed to only use the ~5vdc?

The original USB standard was (is) indeed for 5V, at a maximum 0.5A, for a total of 2.5W. There is no logic involved--just connect to the pins and draw power.

As the USB interface has grown in sophistication through USB 2.0, 3.0, etc., options to draw more power from the interface have been introduced. Additionally, some devices have their own proprietary power standards implemented that are above and beyond the base USB specification.

In general, for the higher-power options, the receiving device and the powering source use some communications logic to perform handshaking when the connection is established and negotiate for a mutually-compatible power delivery arrangement. That is why you have to be careful to select a power adapter that supports a power delivery standard that your power-receiving device is compatible with. It is quite possible to have a power supply that can provide 25W and a device that can consume 25W but because the standards they use to do so are not compatible, the devices end up negotiating to a lower-common-denominator capability that supports only 10W. (I'm making up those particular numbers, but the general point is valid.)

It's also why I regret installing an expensive USB power port in my plane when I had the panel redone ~10 years ago. Charging standards have advanced dramatically since then and now neither my phone nor my tablet can charge at their fastest rate using that source. Fortunately, I also installed extra cigarette lighter ports, and over the years I've just purchased more-capable cigarette lighter power adapters to keep up with the times.