My GPS (Garmin 255WT) cable has the little traffic alert unit incorporated in to the cig-lighter cord, but not on the USB cord. So, if OP's has Traffic on it, he might be SOL on the USB connection.

 

If your GPS is mounted on your bike and use it often like I do to playback music just wired it to the cig lighter wires inside the front fairing never have to worry about plugging in or coming off and the wires are tied to the handle bar for a clean look.

 

I bought a dual USB adapter that plugs into the cig lighter.

 

I did that too and it works perfectly.

Didn't know they had such a thing and now that I have one I see they sell them at the check out stand of convienence stores.

 

Been using them for years. Have two in my truck (one for the front seat and one for the back seat), one in my saddlebag, one in my work travel bag (in case I find myself in a rental car, etc). . . They're awesome.

 

Available for 99 cents delivered from eBay. The one I got is the same exact one that's shown on Amazon, with "Griffin" on it in large print on one side. You can see "Griffin" in small print on the side shown in the pic:

http://www.ebay.com/itm/171200550733

Took about 15 days for delivery.

 

One thing to watch out for with the cheap ones - many phones charge with a 2A input. 1A may cause a slower charging rate. And, if you're using the device while you're charging (especially the GPS), you may lose more power than you charge. So, look for the ones that specify "2A". They may cost a little more, but that's OK.

 

Talked with Garmin yesterday. Nuvi requires 500 milliamperes to charge and run. The USB adapter I have is rated 1 amp x2 so all good. My Nuvi is completely operable other than Traffic Alert as USB cord doesn't have Traffic antennae.