Hybrid batteries are designed and manufactured following the same principles as your cellphone, laptop or conventional car’s batteries. Hybrid batteries are huge by comparison, as they run an electric engine designed to assist combustion engines and improve fuel efficiency. As in conventional cars, alternators charge the hybrid batteries just like those in combustion engines. Some hybrid vehicles, such as the Chevrolet Volt, also allow users to charge the hybrid batteries from an electric power outlet.
Decide what total voltage you need your hybrid battery to deliver. This will depend on the weight of your car, the maximum speed and the acceleration power you desire. The Toyota Prius, a popular hybrid car, delivers a total voltage of 201.6 volts.
Build a series circuit with as many battery packs as you need to meet the voltage requirement on which you decided in Step 1. Connect the positive terminal of each battery to the negative terminal of the next one to build the series circuit. The Toyota Prius' hybrid battery, for instance, loads twenty-eight prismatic nickel metal hydride battery modules, and each module consists of six 1.2-volt batteries.
Place your battery modules in the case and attach it to the body of the car. Specific instructions will vary depending on the car model. Choose a location where the batteries are protected from extreme heat or cold and are not likely to get damaged. The Prius has its hybrid battery set behind the back seat.
Connect your hybrid battery to a car's alternator by running a wire from the positive and negative terminals of one of the battery modules. You will require an alternator designed to recharge a hybrid battery of the same voltage as yours.
Connect your hybrid battery to the vehicle's electrical engine. Again, you must match your battery with an engine designed to run on the voltage and current your battery provides.