Let's say the Electro Charger increased your mileage by 10%. How long would it take to pay for itself in saved fuel?

Even most of the hybrid cars that cost more, take an awful long time to pay back the extra cost with fuel savings.

I wonder how large the capacitor pack would have to be to put out the mentioned 28,000 watts for any period of time. Capacitors usually discharge in a fraction of a second. Also how large would a 30+ horsepower motor be?

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