Take a look at this...
You are indeed lucky. I know of a fellow who pinched a wire in the door jam of his pick up camper shell and the battery had enough juice in it to set the wires and camper shell on fire. These batteries are something to take care of as they can be dangerous. Don't forget to properly recycle the battery as it is against the law in a lot of places to toss it in the garbage. Good Luck Dave.