Theory of USB charging on boats.

[Indolent58]

Given any number of USB charge cables, chargers and mobIle devices on a boat, the number of charge cables that will work with any specific pair of charger and mobile device. will either be zero or one. This has been empirically verified.

[hscrugby]

and that is why i've replaced everything but one older JBL speaker with stuff that uses USB-c.

[bdgWesternMass]

Originally Posted by Indolent58

Given any number of USB charge cables, chargers and mobIle devices on a boat, the number of charge cables that will work with any specific pair of charger and mobile device. will either be zero or one. This has been empirically verified.

There is also the orientation Rule. The USB plug is always oriented the third way you try.