20V

20V denotes a unit of electric potential difference equal to twenty joules of energy per coulomb of charge. In the International System of Units (SI), volt is the standard measure of potential difference, and 20V identifies a specific voltage level used in various electrical and electronic applications. Voltage by itself describes the driving force that can push electric current through a circuit, while current and resistance determine the amount of flow and the power delivered.

In consumer electronics and battery-powered tools, “20V” is a common nominal rating. Many cordless tools and portable devices use lithium-ion battery packs described as 20V or 20V max. These packs typically consist of multiple lithium-ion cells in series. Each Li-ion cell has a nominal voltage around 3.6–3.7V, so a five-cell string yields roughly 18–18.5V nominal. When fully charged, cells reach about 4.2V each, giving a pack voltage near 21V. Marketing often brands this as 20V or 20V max, reflecting the typical operating range rather than an exact constant supply.

Power supplies and charging standards for 20V systems include specialized battery chargers and, in some cases, USB-C Power Delivery, which can provide 20V at up to 5A (100W) in compatible devices. The 20V level is considered low to moderate voltage in safety terms, but appropriate precautions are still advised to prevent electric shock or short circuits.

See also: voltage, battery voltage, lithium-ion batteries, USB Power Delivery.