DC Voltage DropCalculator
Calculate voltage drop for DC circuits including solar PV systems, battery banks, automotive wiring, and low-voltage power distribution. Optimized for 12V, 24V, 48V, and higher voltage DC 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
Common DC Applications
- •Solar PV string and array wiring
- •Battery bank connections
- •Automotive and marine 12V/24V systems
- •Telecom 48V power distribution
- •Data center DC power feeds
- •LED lighting systems
DC Voltage Drop 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.Keep DC runs as short as possible to minimize losses
- 2.Higher voltage systems (48V vs 12V) reduce current and wire size requirements
- 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.