DC Voltage DropCalculator
Calculate voltage drop for DC circuits including solar PV and battery systems.
DC Circuit Parameters
Enter your system values
Total circuit length will be 2× this value
Calculation Results
Critical - Wire size too small for this application
DC Applications
- •Solar PV arrays
- •Battery storage systems
- •Automotive and marine systems
- •Telecommunications equipment
- •Data center DC power feeds
- •Low voltage lighting
DC Formula
I = Current (A)
R = Resistance (Ω/ft)
L = One-way length (ft)
For DC circuits, multiply by 2 for round-trip (positive and negative conductors).
DC Design Tips
- 1.Use larger wire gauges than AC circuits
- 2.Account for voltage drop in both positive and negative conductors
- 3.For solar PV, aim for <2% drop on DC side
- 4.Use parallel conductors for high-current applications
Related Resources
Understanding DC Voltage Drop Calculations
Why DC Voltage Drop Matters
DC voltage drop is critical in solar photovoltaic systems, battery installations, automotive applications, and telecommunications. Unlike AC systems, DC has no reactive components, making the calculation straightforward but the consequences of excessive drop equally significant.
In solar PV systems, voltage drop directly reduces system efficiency and can affect inverter operation. For battery systems, excessive drop can prevent proper charging or cause premature shutdown of connected equipment.
DC vs AC Voltage Drop
DC voltage drop calculations are simpler than AC because there is no inductance or capacitance to consider—only pure resistance. The formula uses the wire's DC resistance directly, multiplied by the round-trip distance.
For DC systems, both the positive and negative (or ground) conductors carry full current, so the total circuit length is twice the one-way distance. This calculator automatically accounts for this round-trip resistance.