What's wrong with my battery?

Here is a simple way to determine what is wrong with your battery if your car does not start.

If the engine cranks well, but the engine will not start, then your battery most likely is OK.  Exception:  European vehicles might crank the engine fine, but the computer will not start the car because the battery voltage is not high enough for the computer to turn on the ignition or fuel system.

If you turn the key to the start position and it cranks a little bit and then goes slower and stops, most likely your battery has a low charge, or it is going bad.  A jump start would get the engine running, but have the battery checked out right away.

When you turn the key you only hear a "click" from the engine compartment, your battery might be ok, but your starter could need work.  Try turning the key really fast from off to start several times in a row and the starter just might catch and the engine start.

If you hear a "click-click-click-click" in rapid succession, your battery is most likely low because you left something on and drained it.  A jump start should get you going.  Have the battery checked anyway.  If you don't have it checked right away, put a trickle charger on the battery overnight.  Chargers are not that expensive, you should have one for situations like this.

If the engine cranks slowly at first and then speeds up and starts, you could have a starter problem, not a battery problem.