In a battery, "V" stands for volts, which is the unit of measurement for voltage. Voltage represents the electrical potential difference between the positive and negative terminals of the battery. This difference in potential energy drives the flow of electrons, creating an electric current. A higher voltage means a greater potential energy difference, capable of pushing more current through a given resistance.
Understanding Battery Voltage
- Voltage is potential energy: Think of voltage as the "pressure" that pushes electrons through a circuit. The higher the voltage, the greater the "push." Volts refer to the potential energy within a battery, whereas current refers to the rate at which the electrons are flowing.
- Difference in charge: Battery voltage specifically refers to the difference in charge between the positive and negative terminals, resulting from the difference in the number of electrons. Battery voltage refers to the difference in charge due to the difference in the number of electrons between the negative and positive terminals of the battery.
- Nominal vs. Full Charge Voltage: The voltage printed on a battery is typically its nominal voltage – the average voltage during discharge. However, the actual voltage can vary depending on the charge level. For example, a 11.1V lithium-ion battery might be 12.6V when fully charged and 9V when nearly depleted. 11.1 volts nominal, 12.6 volts fully charged, and 9 volts should be considered dead. Similarly, a 12V car battery can range from 12.6V to 14.4V. We're generally talking about a 12-volt battery. When we take a closer look, we see car battery voltage can range anywhere from 12.6 to 14.4.
Practical Implications of Voltage
- Higher voltage batteries can generally deliver more power, but this isn't always directly proportional. A higher voltage battery has the potential to "push" more current for a given resistance, translating to more power. A higher voltage battery has the potential to "push" more current--that is, more electrons--for a given resistance.
- The charging voltage must be appropriately higher than the battery's nominal voltage to effectively charge the battery. A very simple answer is enough voltage to yield the desired amount of current to flow into the battery. However, overcharging can damage the battery. During charging a battery shows a rise in voltage.
