Charging ipad

There's nothing specific about leaving a device connected that should damage it. Modern lithium-ion battery charging systems don't continuously charge batteries. They constantly monitor the battery charge level, stop charging when full, and will wait for the charge level to drop before it applies a "top off" charge. Rinse. Repeat. Also - the 100% level you see displayed is kind of a fiction to keep the user from complaining. Most likely it's going between 95-100% (or something similar) of the rated capacity even though it displays 100% if it's continuously plugged in. I've monitored it with coconutBattery and it can show "fully charged" at 96% even though the iPad display says 100%.

Here's an article on this:

https://batteryuniversity.com/article/**-409-charging-lithium-ion

And the diagram that shows how it would terminate the charging, then wait until the charge level to drop before charging again. And at that point it will apply a very low charging current, which is necessary when it's nearly full.

If you charge 24/7 continuously, over several days your iPad’s optimised battery charging may limit the battery to 80% to prevent damage to the battery.

Your iPad will suffer no harm in being connected to external power for extended periods - whether in use or not. This usage model is common in many environments, such Point of Sale and Kiosk applications - and when using an iPad with external monitors in desktop computing applications.

Your iPad will optimally charge your iPad battery, modifying its charging strategy as appropriate.

More information about iPad’s battery management can be found here:

About iPad and iPhone Charge Management Feature – Apple Support

You might also find this information helpful:

Batteries - Maximizing Performance - Apple

Your iPad will automatically regulate and optimise charging - and will not overcharge the battery.  When connected to a Power Adapter for an extended period of time, such as when used in Kiosk or PoS (Point if Sale) applications, iPad will change its charge management strategy - and reduce the maximum battery charge level to about 80% of maximum capacity. This modified charging strategy is designed to reduce chemical ageing that might otherwise occur if 100% charge is maintained at all times.

Nominal 100% charging will be restored when a normal charge/discharge routine is restored.

apple_mac_user_01 wrote:

If you charge 24/7 continuously, over several days your iPad’s optimised battery charging may limit the battery to 80% to prevent damage to the battery.

That's not available for iPads. That's an iPhone feature, with a similar feature for newer Macs.