Just so, but maybe also good to bear in mind that many, if not all recent Garmins need a Garmin cable to charge. How does it know a generic from one of its own? Garmin added a 17.3k resistor between pin 4 and ground (5) Reference: http://pinoutguide.com/GPS/garmin_nuvi_power_pinout.shtml
Relax, it seems from this reference and others, that the unusual resistor value is not critical; 18k - 22k reported as working fine, but the resistor must be present. That's how Garmin knows it own! -and now that you know, a generic cable can often be given such a resistor to make it acceptable to the Garmin device.
-Or you could just pay top dollar for the Garmin part and not repair anything.