Question: how much power is needed to start a car?
Answer: I'd say current draw 50 amps (small, warm 4 cylinder) to 300 amps (cold V8) at 12V. That works out to 600 to 3600 watts. Then, it might take 0.5 second to start a warm, well tuned motor and 5 seconds to start a cold, finicky motor. The current value will vary with a given engine, more so with a four than an 8.