So you mean playing a game/doing anything else power-hungry while charging the device? While that's at no time the best way to handle a rechargeable battery as it gets quite hot, it is, if you really want to do that, a question of power input versus output. As these devices pretty much all charge via USB (right?), the input is determined by the USB specifications, which are 5V voltage, 0,5A current -> 2,5W of energy. Often, USB devices specifically for charging have a higher curren, the maximum I've seen was 5A, but you shouldn't expect a lot more than 1A in transportation, maybe even just 0,5A (which is btw what most laptops give you, and the Pandora afaik too).
The output is even more unclear, as you need to factor in display brightness, CPU usage, memory usage, WLAN, Bluetooth and a lot more. The GPD WIN will probably do better than any tablet with the same CPU (as the big displays eat up a lot of energy while the keyboard doesn't), but it's impossible to say how good or bad any device does until it's tested. Even the Pyra will probably have problems playing some high-end games/emulator while charging, but then again, its battery is huge. I'll personally be happy if I can play Heroes 3 VCMI for 10 hours on the Pyra while it's on a charger
Yeah exactly what I mean. Especially when I'm on a long trip to Asia, I'm used to use my android phone, and to plug it to the USB port to use it when It runs out of battery.
I know that people like to take power bank, but I'm not this kind of people, that's why I wondering if it's possible to charge and use it while plugged into a USB port, because it's meant to be played on the road, even if it runs out of battery.
I understand what you are saying, maybe that someone has a x5-z8500 atom tablet can give a try on a car.