Solar Electricity
Solar DC Cable Loss Calculator
Solar DC Cable Loss provides a checkable estimate of DC cable loss. It is intended for scenario comparison, not as automatic approval of a component or installation.
Enter values for DC cable loss
Do not mix values recorded under different conditions.
Preparing the calculation
Use site-specific irradiance, temperature, shading, and equipment data. Do not combine a worst-case value with unrelated nominal data.
Confirm decimal placement whenever a source uses a different unit scale. The broader analysis may also use Motor Cable Power Loss Calculator.
- Array current
- Default example: 15 A. Enter array current in A.
- Circuit resistance
- Default example: 0.3 Ω. Enter circuit resistance in Ω.
DC cable loss: calculation method
The displayed result follows loss = I²R. Only Array current and Circuit resistance enter the numerical result.
For the example shown, DC cable loss equals 67.50 W. Treat that value as a demonstration, not a recommendation.
Calculate DC cable loss from array current and circuit resistance. For the companion required array size calculation, open Off-Grid Solar Array Calculator.
Interpreting the answer
The primary answer, DC cable loss, describes only the entered scenario. Compare it with module, inverter, controller, and storage ratings.
Keep the input set beside the output so another reader can reproduce it. If you also need internal resistance, continue with Source Internal Resistance Calculator.
Using the answer downstream
Record array current and circuit resistance with DC cable loss. Include the operating state and data source.
Pass DC cable loss before applying any display rounding. Round at the final reporting step.
What the formula leaves out
Use round-trip conductor resistance at operating temperature.
Depending on the application, account for seasonal resource variation and controller or inverter operating windows. Test an additional scenario when an omitted effect has a plausible range.
Base energy estimates on the limiting season rather than an annual average alone. For wire loss, use Wire Power Loss Calculator.
Common questions before using the result
Can I select equipment from this number alone?
The calculator does not approve equipment or supply an unexplained margin. Compare against cold-voltage, hot-voltage, current, energy-yield, and controller limits.
Should intermediate values be rounded?
Keep full precision while transferring DC cable loss; round only at the final reporting or selection step.
Should a blank measurement be entered as zero?
Leave the case unfinished until the real value is known rather than entering a placeholder zero.
How should I prepare the Solar DC Cable Loss inputs?
Measured and rated values can represent different states. Base energy estimates on the limiting season rather than an annual average alone.