How to disable auto charge when my iPad plugged into my Mac?

Plug it in to a USB hub. When my ipad is connected directly it charges, but when its plugged in to a hub thats connected the ipad reads "Not Charging" next to the battery icon.

No, you can't. The only way this could be possible would be through disabling output charge from your Mac, but that's not possible either as far as I know. Another possible way would be to use a special kind of USB cable which allows data exchange without charging the device.

I looked around for a "data only cable" or one where you could "disable charging," and found nothing online that seemed relevant. It may be possible to have a "data sync only" with a Nokia device, but not an Apple device.

I found articles describing altering the 8-pin, but those resulted in shorting and other problems, so this is not advisable.

I also identified no apps that disable charging in the iOS App Store.

On thing you could do is turn on iTunes wi-fi syncing. Plug your iPad into your computer. Open iTunes. Click the checkbox that enables wi-fi syncing under "Options."

My iPad Pro says that it has to be plugged in to sync automatically, but I was able to do it manually without it being plugged in. Just go to General > iTunes Wi-Fi Sync > Sync Now.