[Imp]

Not checked CPU usage as never had a problem but think it works hardest when purchasing units for some reason as can cause my fan to run, so setup on your tower possibly. If your fan is running flat out as in noisy points to it getting hot could need nothing more than a simple vac inside dust builds up stop heat sinks working.
The obvious do you have it set to hibernate or shutdown after 5mins of no input on batteries, watching the other sides turn might exceed that.