Is the battery series capacitor useful? What should I pay attention to?

The withstand voltage of the capacitor must be more than twice of 60v. Here, I tell you responsibly that no matter whether the batteries are connected in series or in parallel, the mileage will not be increased, and the battery discharge speed will be accelerated, because the capacitor is also an electrical load relative to the battery. When the capacitor is connected for the first time, the battery must first charge the capacitor (battery discharge), and the capacitor itself will not generate electricity but only store electric energy. Connecting a capacitor is like pouring a coin (battery) into a capacitor, and the result is the total amount of money. I hope everyone will stop believing those irresponsible rumors on the Internet.