State the reason you wish to close your account. If you have a copy of the EIN Assignment Notice that was issued when your EIN was assigned, you should include that when you write. Otherwise, be sure to include the complete legal name of the entity, the EIN, and the mailing address.
After all, if your iPad doesn't have any power, it doesn't work. The iPad's battery is generally pretty good, but if your battery is starting to fail, you've got a problem. You can't easily swap out a failing battery for a new one because Apple designs its products with solid cases.
Using an iPad charger, either the 10W or newer 12W will absolutely charge your iphone faster. In fact, almost twice as fast. However there's some speculation that it may shorten the battery's lifespan. I've had no problems using an iPad charger on my 5S and it's charged in no time.