iPad does not charge when connected to computer

[gsusser]

I had this issue with my iPad 3 and have it again with my new Air. Or is it an issue? When the iPad is connected to my iMac, it does not charge and I get a message to this effect. Is this normal?

I'm using the same cable I use for my iPhone. Is there a difference in cables?

 

[HiddenPuppy]

I had this issue with my iPad 3 and have it again with my new Air. Or is it an issue? When the iPad is connected to my iMac, it does not charge and I get a message to this effect. Is this normal?

I'm using the same cable I use for my iPhone. Is there a difference in cables?

Normally the USB port on a computer does not furnish enough power to charge the iPad. Even though it says it is not charging I have found on my computer it says that but if I leave it pluged into the computer for a while then unplug it the percentage of charge has increased.

However, it will not get a full charge.