How to Easily Calculate the Conversion of Volts Amps & Watts


Basic electric theory states that:


Volts are a measure of the force or pressure under which electricity flows.


Amps are a measurement of the current flow rate of electrons.


Watts is a measurement of electrical power created.  1 watt is equal to one joule of energy per second.


In the solar Industry, the ability to easily convert volts, watts and amps is necessary for every part of the business from system sizing to procurement of solar panels, inverters, and balance of system components like connectors and wiring.


My colleague Stewart Wadsworth, an educator from Boots on the Roof treated us to the use of an easy to remember chart to calculate volts, amps and watts. 


To use this conversion chart, you will need at least two of the three desired electric values from a specific load requirement.  From there, you can calculate the third.  Simply draw a triangle, then place a W for watts at the top. Then place a V for volts at one of the bottom corners and an A for amps at the remaining corner.



For an example of how the conversion chart works, let’s assume a solar panel rated at 60Watts, 12Volts and 5Amps.


The formula for Watts is Volts times Amps.  To use the chart, cover the W in the chart with a finger and use the remaining visible chart calculation of V multiplied by A.  Using our sample panel data, 12 Volts multiplied by 5 Amps equals 60 Watts.


The formula for Volts is Watts divided by Amps.  To use the chart, cover up the V with your finger and use the remaining chart calculation of W divided by A.  Using our sample panel data, 60 watts divided 5 Amps equals 12 Volts.


The formula for Amps is Watts divided by Volts.  To use the chart, cover up the A with your finger and use the remaining chart calculation of W divided by V.  Using our sample panel data, 60 watts divided by 12 volts equals 5 amps.



By: Rick Contrata


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