How to disable Amazon EC2 charging?

There is no way to control how much you will have to pay on AWS, that's why I wouldn't use it.

Amazon is really vague on the free tier (for instance it's not very clear whether the storage volume comes with the instance is counted against free EB2 storage quota). There are so many ways you can get a bill for using the free tier.

Yes you will be billed after 12 months, if you don't terminate all the instances and detach all storage volumes.

So many people have complained about Amazon's billing practice. Amazon has never changed. I guess this is the way Amazon decided to make $. Let you in for "free" but you will most likely accidentally spend some money. If you decide to use it, you won't know how much you will have to pay. If you have the capability to use colo/dedicated server, you might find out it's actually so much cheaper to go with a fixed monthly payment instead of billing based on usage.

It is currently not possible to disable charging. You might need to go over the free tier (for example if you setup a production environment, you might not want it to be killed automatically by amazon). Google App engine is a bit different because it is free if you have zero http requests, so it will just stop serving your app.

If you delete your credit card on your account, amazon will still charge it if there is an unpaid balance.

Amazon will not remind you that you will go over your free tier, so I would recommend to put a little reminder in one year on your calendar in one year to not forget to shutdown your server.

I ended up closing my account by visiting the account page

At the bottom of the page you will find "close account"

With Amazon EC2, you are billed per hour of usage. If you are a new user, your account is credited with something like 8,760 free hours (24*365) which expire after 1 year. (I'm working from fuzzy memory here, so double-check the official terms instead of taking my word for it.)

After your free hours expire or are otherwise used up, Amazon EC2 will begin billing for normal hours (which can be as cheap as 2 cents per hour -- http://ec2instances.info). There is no such thing as a "free" EC2 instance.

So, to answer your questions:

• Does Amazon EC2 AUTOMATICALLY charge you after one year?

Once your free hours are used up or expire, then you are automatically billed for normal hourly usage.

• How to disable the automatically charging function?

You can't. All EC2 instances cost money. You are responsible for keeping an eye on your account and ensuring that you don't go over your free hours if you don't want to pay anything.