Xbox controller not responding.

This question is in quite a few places on the forums, and in various other locations around the internet, but I have not found a satisfactory solution, or even a likely cause of this issue. I have 2 xbox controllers. I can turn on my xbox, with the controllers.
At various lengths of use, the controllers will stop functioning correctly. It seems as though the connection is lost. The light on the controller is still on, but it always brightens, right as this issue happens, on both controllers. Only fix thus far I have
found is to Power Cycle the console, with a controller connected via USB, then, after the xbox is fully loaded, while the controller is still plugged in, turn off the console normally. After it is powered down, remove the cable from the controller, then power
on the system, via the controller. IF the controller is not plugged in, it will turn on the xbox, but the light will go and stay bright, and will not have any effect on the console. Now, one of the controllers is assigned to me, and requires my face or a password
(to keep the kids from buying movies and games). When the system is powered up by that controller, and not plugged in, it takes me to the prompt to sign in my profile. This does not happen with the other controller. This tells me that the controller is Communicating,
at least at some point, with the Xbox. Sometimes it can go for hours, without issue. Sometimes, mere minutes, to the point where I just opt not to use my xbox. I have tried the soft reset, and the factory reset. I have made sure my controllers are up to date.
I have downloaded and installed the update manually. All to no avail. Any new solutions, or causes I can avoid, would be much appreciated. Thank you.

:)