Today, my car didn't start. I think that the crank was turning over because I could hear the loud sound a car makes just before starting up but the car was not starting. Anyways, I called a mechanic. He changed the battery and the car works now. Coming to the point, I initially thought that since the crank was turning, there was no problem with the battery (like a weak battery) since I presume that turning over the crank requires a lot of energy. But in this case, it looks like there are parts in a car that requires even more energy than the starter motor, in the starting process of a car. So my question is, could you present a generic comparison of energy required per car part? Especially, which parts in starting process require more energy than the starter?
EDIT: Or am I completely out of the ballpark by thinking that there are parts that require more energy than the starter?