when pluged in the ipad says "not charging"

Assuming your cable and/or charger is not broken, it's fairly straightforward to clean the charging port on the iPad and the charging tip of the cable. You can clean just the tip (pins) of the charging cable in rubbing alcohol. Isopropyl alcohol is commonly used to clean circuit contacts. Just find a way to get some in to the charging port but do not pour it in!! Put a little bit on a toothbrush or something. The tip of the cable is easy enough to clean even with a cotton swab.

And as had been said before, the iPad battery is larger and takes more juice to charge than what a standard USB port or standard iPhone charger can provide; that's why they come with different chargers than iPhones which have smaller batteries.

Try using the original charger

I was having this issue until I found my old original apple cable and plugged that between ipad2:30pin / macbook pro:usb. Viola, my ipad no longer said 'not charging', and battery bar turned green with lightning bolt. So I suppose we have to use the original cables, at least in my case. I noticed that the 30pin side is almost double the size of my other non-apple store bought cables. Hope this may help.

I am now a happy camper as I can use my ipad as extended monitor without having to buy a portable monitor!

me neither pure *****

it's always worked before is it the cable getting old