 ## Glossary: V

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V

Volt: The unit of measure for voltage. Voltage is the electrical pressure which forces the current to flow in a conductor such as a wire.

VA

Volt-Ampere: Voltage (V) multiplied by the current (ampere); apparent power. For instance, a device rated at 10 amps and 120 V has a VA rating of 1200 or 1.2 kVA.

VOC

Open Circuit Voltage: The maximum possible voltage across a PV array, module, or cell. The voltage across the terminals of a photovoltaic cell, module, or array with no load applied when the cell is exposed to standard insulation conditions, measured with a voltmeter.

Volt (V)

The unit of measure for voltage. Voltage is the electrical pressure which forces the current to flow in a conductor such as a wire.

Volt-Ampere (VA)

Voltage (V) multiplied by the current (ampere); apparent power. For instance, a device rated at 10 amps and 120 V has a VA rating of 1200 or 1.2 kVA.

Voltage

A measure of the force or "push" given the electrons in an electrical circuit; a measure of electrical potential.

Voltage Drop

Loss of voltage (electrical pressure) caused by the resistance in wire and electrical devices. Proper wire sizing will minimize voltage drop, particularly over long distances. Voltage drop is determined by four factors: wire size, current (amps), voltage, and length of wire. Water analogy: friction loss in pipe.

Voltage, Nominal

A way of naming a range of voltage to a standard. Example: A “12 volt nominal” system may operate in the range of 10 to 20 Volts. We call it “12 volts” for simplicity.

Voltage, Open Circuit

The maximum possible voltage across a PV array, module, or cell. The voltage across the terminals of a photovoltaic cell, module, or array with no load applied when the cell is exposed to standard insulation conditions, measured with a voltmeter.

Voltage, Peak Power Point (VPP)

The voltage at which a photovoltaic module or array generates at the highest power (watts). A “12 volt nominal” PV module will typically have a peak power voltage of around 17 volts. A PV array-direct solar pump should reach this voltage in full sun conditions. In a higher voltage array, it will be a multiple of this voltage.

Voltmeter

A device for measuring the voltage difference between any two points in an electrical circuit.

Volts per Cell (VPC)

The voltage of each individual cell, each cell in a block or each cell in a battery. The system voltage of your battery is the sum of the individual volts per cell.

VPP

Voltage, Peak Power Point: The voltage at which a photovoltaic module or array generates at the highest power (watts). A “12 volt nominal” PV module will typically have a peak power voltage of around 17 volts. A PV array-direct solar pump should reach this voltage in full sun conditions. In a higher voltage array, it will be a multiple of this voltage.