How do I use the DC Voltage Drop Calculator?

Enter your system parameters into the calculator fields on the left and click "Calculate". The results will appear instantly on the right, showing you the recommended values for your Victron energy system.

Is the DC Voltage Drop Calculator free to use?

Yes, all tools and calculators on Victron for Less are completely free. They are designed to help you plan and optimise your Victron energy system.

DC Voltage Drop Calculator

Calculate the voltage drop across DC cable runs in your Victron energy system. Essential for ensuring your cables are correctly sized and your equipment receives adequate voltage.

Enter Your Values

System Voltage

Cable Length (metres, one way) (m)

Current Draw (Amps) (A)

Cable Cross-Section Area

Results

Enter your values and click Calculate to see results.

How This Calculator Works

Voltage drop occurs in all electrical cables due to the resistance of the conductor material. For DC systems, this is calculated using:

V_drop = (2 × L × I × ρ) / A

Where: L = cable length (one way, metres), I = current (Amps), ρ = resistivity of copper (0.0175 Ω·mm²/m), A = cable cross-section area (mm²)

The factor of 2 accounts for the return path (positive and negative cables).

Acceptable Voltage Drop

Under 3% — Acceptable for most installations
3% to 5% — Marginal, may cause issues with sensitive equipment
Over 5% — Unacceptable, will cause performance issues and potential damage

For Victron inverters and chargers, keeping voltage drop below 3% is strongly recommended to ensure optimal performance and to avoid low-voltage alarms.