iPad battery slow charging on 4th generation iPad, will Apple replace if there is no warranty?

If your iPod Touch, iPhone, iPad or iWatch is Broken

Apple does not usually fix iDevices except for screens – iPhone Screen Repair & Replacement - Official Apple Support– and minor work they can do in their shop. Instead, they exchange yours for a refurbished or new replacement depending on the age of your device and refurbished inventories. On rare occasions when there are no longer refurbished units for your older model, they may replace it with the next newer model. You may take your device to an Apple retailer for help or you may call Customer Service and arrange to send your device to Apple: You can make an appointment at the Apple Retail Store - Genius Bar and take it in for service. You can also look for an Apple Store - Find a Store - Apple. You will find respective repair costs from the appropriate link:

• iPod Service Support and Costs.
• iPhone Service Support and Costs.
• iPad Service Support and Costs.
• Apple Watch Service Answer Center.

You'll have to go to an Apple Store to find out for a 6 year old iPad 4.

An out of warranty battery replacement, for an iPad, is normally $99 U.S.D., plus tax.