Answer:

When you connect batteries in parallel you connect positive to positive and negative to negative. With a parallel connection you are increasing the size of the pool of power you have but the voltage stays the same as the original batteries. To connect in series you connect positive to negative then you get one positive from one battery and the negative from the other battery. When you connect two batteries in series it adds the voltage up. So if you have two 12 volt batteries and connect them in series you will end up with 24 volts.