How many lemon batteries would it take to start a car?

One. “Hey, chap. you couldn't help jump my car, could you? I can give you a lemon” you might even get to keep the lemon in which case: zero. On a practical note: your car still has its battery, it's just flat. read more

5,000 batteries in parallel to get the 100A current, and then 30 of them in series to get the 12 volts, for a total of 15,000 lemon batteries to crank your car. This is just a rough “order of magnitude” estimate. read more

For a smaller vehicle or a half-dead battery, 200 amps might be sufficient. You should check your vehicle's manual and see what the 'cold start' amperage requirement is. read more

A battery cell is an electro-chemical device that produces a voltage. The voltage across one cell is dependent on the chemicals used. The voltage across a battery depends on the type of chemicals used multiplied by the number of cells connected in series. For example the older type lead acid car battery developed about 2 V per cell. read more