Phones work great till you lose your signal. In the mountains of NC you will lose your signal, out in the west you will lose cell signal.

 

I use a ram mount which attaches to my windscreen. The battery will last a few hours, which is usually enough. If I have to, I'll plug it into a power outlet which I can attach to my battery tender lead. I rarely use the GPS, so this setup is cheap & works well.

 

Smartphone GPS update:
Many Nav Apps available, some are free, that download the maps to your SD Card then only relies on the GPS signal to work. Download the U.S. map, or whatever country, via WiFi before your trip, no cell signal needed. If you use Google Maps, or the like- fine - but you need this app as a backup just in case.
I downloaded one of those Nav Apps to my 11" Tablet that is only WiFi, and it works just fine.
No, I have not mounted that slab on the 'King!
And - There are Garmin and Tom Tom apps at the Google Play Store that will allow your Smartphone to do all any GPS unit can do, rates are daily, monthly, or annually - you choose.

 

One of the things I enjoy about riding is turning my phone off...no tunes, no calls, no voices in my head...

 

How do you turn off the voices in your head?

 

If you are considering the Road Tech 660 or 665, read as many reviews as you can find first. This is a expensive unit and mine happens to be junk. Some are quite happy with theirs......spoke with a guy that has the same unit as well as the older model (550). His 660 is at home and he used the 550 for his long sturgis trip. I only have this one and might as well have left it at home. Very undependable, giving conflicting instructions and couldn't find it's own backside.
Just throwing it out there.....