The heating issue is resolved now that I am using a fully charged 18650 3120mAH 3.7V 15A battery.
The measured voltages changed very little:
- numbers from top left to right (5.3V; 5V; 3.15)
- numbers on bottom, left to right (5.01V; 8.82V; 1.6V; 3.29V; 3.29V)
The LED strip in the blade is still not changing colors (i.e. when spectrum is activated). - I will open a new thread for that issue, if required, after some additional investigation and work on the wiring.
Thanks to those who provided helpful replies.
*How do I mark this thread as solved?*