battery problems

[psycho123]

I was having problems with the "check engine lite" on my '97 Tauras coming on for no apparent reason.

I also needed a new battery. My mechanic said my old battery was not the right one.

After I drove off , the lite on my dash went out and has stayed off.

Why are batteries specific to type of car?

[Toureman]

Big engined cars need big and more powerful ones to start the engine, small cars need small ones, also depends on how many electric extras are fitted..

Also all cars have different designs so have different shape and sizes of batteries..