The answer is yes and no. If your engine is properly tuned, it should start within 3-4 seconds after cranking. This does NOT take much time to re-charge the battery. If you have to crank the engine for 20 seconds, there is a problem you should look into. The battery and charging system work together to supply and replenish. Revving the engine does very little, unless there is a problem. Have your engine's charging system tested for free at an Auto Zone, or other. Good Luck!!