Let's say you have a circuit connected to a 15 volt battery. If current travels from the negative terminal of a 15 volt battery to the positive terminal, the voltage is said to rise 15 volts. I believe this is right, but correct me if I'm wrong. Assuming that is right, then does that mean that the electric potential at the negative terminal of the battery is zero volts and the electric potential at the positive end of the battery is 15 volts, because voltage is the difference in electric potential, so voltage = vf - vi = 15 V - 0 V = 15 volts. Am I correct in thinking this is the case? If so, can someone explain to me why the electric potential at the negative end of the battery is zero volts? Specifically can someone explain to me why the electric potential at the negative terminal of the battery is zero volts "REGARDLESS" of what else is in the circuit. So why is the negative terminal of the battery always zero volts in electric potential regardless if you have nothing but a wire in the circuit, 2 resistors, or 7 resistors, etc...? I could really use some help with this, conceptualizing why it's zero electric potential at the end of the circuit, regardless of what is in the circuit is killing me inside, because I can't grasp the concept. Thanks in advance.