Hi @Ibrahim,
How are you testing this? The electronics enclosure isn’t designed to operate in air for extended periods, which is especially the case for acrylic enclosures. We would generally recommend testing with the vehicle in water, as that helps keep things cool.
If you do need to test in air it’s recommended to have some form of ventilation. At absolute minimum keep the vent plug open, but preferably keep the electronics out of the enclosure, and ideally have a fan or similar to keep them cool.
The 150% CPU load is unusual, but it’s possible the load is that high because of the throttling from the overheating. Does it consistently get that high when you turn on the vehicle (after it’s had a chance to cool down)?
You also may be interested to try BlueOS, which is the replacement for our old Companion software. It should have lower CPU usage, and accordingly may run a bit cooler.
A 5V6A power supply is definitely recommended for the vehicle to run properly 
That generally shouldn’t be a requirement unless you’re running some additional software that’s using a lot of CPU, but it also shouldn’t do any harm, and could be quite helpful.