Originally Posted by
Fly2High
I think the iPhone 6 is 1800mAh so you can still charge it a bit more a second time.
Due to unavoidable inefficiencies, you get less mAh out of them than they are rated at (it might be around 20% less).
Originally Posted by
Fly2High
I think one of these chargers weighs equal to or less than a Garmin so if you are going to have a phone as well as the Garmin, there is really no difference in total weight carried as well.
The Garmin is likely easier to mount and (by itself) it's better protected from weather. That is, there are some reasons a Garmin would work better for some people.