How many amps is the fuse rated for? I'm finding it strange that the electric motor on the air compressor didn't blow it, but a USB adapter did. The USB chargers are typically just a few hundred MA, much less than just about any fuse. I think there has been a wiring mixup somewhere, or the particular cigarette lighter you used is defective.
I prefer the powerlet/bmw type sockets for motorcycle use, though some have had good results with marine-quality cigarette lighters as well.
|