I have one of these for power distribution and control at the moment. I want to move away from the RPi and astroberry as I am having so much issues with it, and I therefore want to power the 3Q from the box and and have the box as a dew heater controler. and leave the rest for the 3Q.
I have intended to make a cable like the one you described. I aqcuired this cable and will solder aDC plug to the open ends. The cable is said to be used to power a Raspberry Pi 4., which would be 5V and 3A max. But I will be running up 2A at about 13.7V for my 3Q. The thing I am having difficulties with is finding out if the cable I bought cold handle powering my 3Q. I am myself such a noob with electronics that I can not tell.

I have not begun using batteries to power my stuff yet. Still keeping it close enough to my house where I can use a wall outlet for the Astrolink power distribution box.

In this review the 3Q seemed to have much lower idle power consumption and a bit lower stress power consumption than running Windows. So, I can see it not getting quite as hot runnign linux. I am running Windows, and it does get quite hot. Uncomfotable to touch. Although, I have only had it running indoors, not outdoors where it would be a fews tens of degrees cooler.

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