How to turn on my ipad if it only has a battery sign and it isn't responding to a forced power.

One suggestion online is to press the sequence of buttons shown in the article below:

https://mashable.com/2015/11/20/apple-ipad-pro-screen-black/#coWqk0nqv8qB

Quoting:

"Learn what to do if your iPad Pro doesn't respond when you press buttons or tap on the screen, and the screen is black," Apple's message reads. "To get back to using your iPad Pro, force restart it by pressing and holding both the Sleep/Wake and Home buttons for at least ten seconds, until you see the Apple logo."

Hi:

Try a hard reset. It forces your iPad to turn Off and then On.

Hard Reset Your iPad. A hard reset forces your iPad to abruptly turn off and back on, which will usually fix the problem if your iPad has frozen on the Apple logo. Press and hold the power button and the Home button simultaneously until the Apple logo appears. Then, let go of both buttons.

You can try these:

1. Force Restart iPad:
Hold the Home button and Wake button at the same time for about 10 seconds. Your find your device vibrating and get out of the iPhone boot loop.

2. Try an iPhone system recovery software
If your iPad cannot be force restarted, TunesKit iOS System Recovery is a wildly accepted tool to make your iPad back to normal with almost every problem solved.

If your iPhone iPad or iPod touch doesn respond or won turn on

Go to settings, applications, running and click safari and force stop/force close

try this steps:

Restarting, resetting, or Force quitting the apps.
Restart iPad: Press and hold the Sleep/Wake button until the red slider appears. Slide your finger across the slider to turn off iPad. To turn iPad back on, press and hold the Sleep/Wake until the Apple logo appears.
Force quit an app: Press and hold the Sleep/Wake button on top of iPad for a few seconds until a red slider appears, then press and hold the Home button until the app quits.
If you can't turn off iPad or if the problem continues, you may need to reset iPad. This should be done only if turning iPad off and on doesn't resolve the problem.
Reset iPad: Press and hold the Sleep/Wake button and the Home button at the same time for at least ten seconds, until the Apple logo appears.

Hello,

If you charge your iPad on a power adapter, the iPad should respond while charging, except if your iPad battery is so low the apps need more power to run.

If you charge your iPad on the USB port of your computer, it is normal you cannot use your apps as the iPad is not only in battery charging mode but also in synchronizing mode with iTunes in the computer. You should lose the habit to charge the iPad on the PC and use a dedicated power adapter instead, as dedicated power adapters charge the iPad battery 2 to 4 times faster than the USB port of most computers.
USB port power: 2.5 Watts in general (5 volt x 0.5 A = 2.5 Watts)
iPhone charger: 5 watts
iPad charger: 10 or 12 watts

Hold the menu button while pressing the power button. It will reset.

This tutorial will explain how to force your iPad to restart if it gets stuck or freezes up.
Forcing your iPad to restart will not cause any loss of data - with the possible exception of any work you were doing at the time the iPad and/or App froze, forcing you to restart it.

Click and hold down the Sleep/Wake button (located on the upper-right corner of your iPad). While you're holding down the Sleep/Wake button, hold down the Home button as well (located on the front of your iPad at the bottom). Hold down both buttons until your iPad powers off. It will reboot and start again with a small silver Apple image on the screen. It takes about 30 seconds for the iPad completely start up.

This sounds like a hard ware issue with you wifi antenna. Restore your device using iTunes. If it is still grayed out take it in for service at a local apple store or authorized service provider.