Can you elaborate on this comment? Unwind the whole cable when charging?
I have mine coiled in a much bigger loop around the connector
but I don't uncoil when charging as my car is quite close.
Okay, I don't know for sure with DC, but before I installed my NEMA 14-30 plug and conduit,
I was using a NEMA 5-15 extension to connect my UMC to a plug wall.
I needed just a few feet, so I kept my extension unrolled, but I noticed that the 120 V - 12 A AC
was enough to warm up my cord. I didn't experienced this after making a single big loop.
So I don't know if there is a difference between DC and AC at this point,
or it was only the resistivity heating which is free to escape upward when you have a straight line
as opposite to have the wires in middle of the loop not able to dissipate and heating up little by little.
Note: For the story, I build my own microwave ham radio klystron transmitter and my own antennas.
At those frequencies if your transmission line and antenna are not correctly tuned, you have a reflection mechanism
called Standing Wave Ratio (SWR) which generate losses of power. I never had the money to buy any sophisticated meter,
so I was putting my hand along my coaxial cable to estimate if there was some noticeable heat loss, to make some adjustments.
If you are interested about this subject, there are some good ElectroMagnetic Field (EMF) detector Apps for smartphones.