If you have developer mode enabled use the
$top
command to check which processes are using the most CPU. There is an issue with the device idling at high battery usage when often causes the CPU to overheat under high processer load. This is usually caused by an issue in the home screen where the device is trying to do something but cannot do it. To resolve this just use the commang $kill **** replacing the stars with the process no of the process using the most power. This is normally caused by a process called meego-touch home. After this I have had no issues. It is discussed in further detail in the "high idle consumption" thread.