Voltage Drop Calculator
Voltage Drop Calculator Instructions
When dealing with solar and 12V systems, the first thing we often look at in terms of wiring is the current or amperage rating. However an area that isn't at first obvious is the voltage drop. Using the Voltage Drop Calculator the voltage drop can be calculated given the length, cross section and current. For low voltage systems the voltage drop can be quite significant meaning that some appliance won't work as expected.
The Voltage Drop Calculator is a tool which will help you determine the voltage drop and thus the impact on your system. Using a trial and error approach with the Voltage Drop Calculator you can use the Voltage Drop Calculator to help determine the cross section of the wire you need.
Length is the length in metres for the single run of wire. There's no need to think of the return wire as this is taken into account for you with the Voltage Drop Calculator.
The current is entered in amperes.
The reason for including voltage in the Voltage Drop Calculator is by entering voltage, the watts is determined for you. Often devices are rated in watts. If for example you have a 12V TV that is rated at 60W, then you can either calculate this is 5A, or you can adjust the current until the watts is close to the value you want.
The cross section of the wire is important. It can be tricky. IF you purchase wire from a solar
provider the cross section is often stated in mm such as 4mm which really means the cross section of
the wire is 4 mm squared. For the Voltage Drop Calculator I use a caliper to measure the diameter of the wire and use the
formula πr² to determine the cross section where r is the radius, which is half the diameter.
The voltage drop in volts is the difference you'll see between one end of the wire to the other end, for the length of the wire, drawing a given amperage, through a certain thickness of wire. If the voltage drop is too much some appliances may not work.
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The Voltage Drop Calculator comes with no warranty expressed or implied. The Voltage Drop Calculator is only for informational purposes and is not guaranteed to be error free. The information on this page is not intended to be advice.