Is the USB port for only charging I phone ? The I pad will not charge .

 

I've found the USB port to be very weak. It will charge a device (very slowly) if it is turned off, but my phone will slowly discharge if it is plugged in and running a navigation app.

 

The iPad requires more power to charge than an iPhone.
While both use the 5v line of the USB, the iPad requires ~ 2 amps (10 watts total) vs the ~ 1 amp (5 watts) of the iPhone. I believe the USB standard is .5 amp (2.5 w), which is what you vehicle would be.
2.5w is enough to charge the phone, but not enough for the iPad.


edit: the fact that the car only puts out 2.5 w is why if the phone is being heavily used it will still drain the battery. If you plugged it in to a 5w plug it would probably charge very slowly if used with something like navigation (uses gps, cellular and display all the time).

 

That would fit with what I was seeing. The solution for me was to get a USB charger that plugs into the 12v outlet.

 

very good information! thank you!