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You need to know three things: how many amps, how far the cable runs, and what voltage you're working with.
Feed those into our calculator and get the right cable size—plus the voltage drop and power loss your system will actually experience.
DC CABLES Only
Cable Type
Select system type.
Cable Sizing
Results
Status
Cable Size
Voltage Drop V
actual loss
Voltage Drop %
of system
Power Loss
watts wasted
Max Current
capacity
Bend Radius
mm min
Cable Outer Diameter
mm
Cable info will appear here.
WHY DC ONLY ?
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This calculator is for DC systems only: solar arrays, battery banks, wind turbines, off-grid inverters.
DC circuits use resistance calculations only. This makes voltage drop simple and linear: V = I × R.
AC systems are different. They require reactance calculations, power factors, and load variations that change the formula entirely. AC installations use BS 7671 (UK), NEC (USA), or local wiring codes instead.
Common DC applications:
- Solar PV strings (DC output from panels)
- Battery bank interconnects
- DC bus to inverter (pre-inversion)
- DC loads (lights, motors, pumps)
- Marine systems (yacht, boat: 12V/24V)
- Off-grid renewable systems
For AC circuits (wall power, AC distribution from inverter output), consult BS 7671 or NEC standards instead. Those require different cable sizing methods.
Engineering-Backed Off-Grid Power Solutions
25+ Years Serving Telecom, Marine, Water Pumping & Critical Infrastructure
THE OFF-GRID POWER EQUATION
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Efficiency = Smaller Systems = Higher Reliability = Lower Cost
Efficiency isn't just about saving watts—it's about systems that work when nothing else can. Smaller, smarter systems mean higher reliability, lower costs, and no unexpected failures at remote sites. This is the formula that powers thousands of installations worldwide.
Our founding engineers learned this the hard way. As boat owners, we survived miles from power lines where every watt mattered. In 1997, when solar cost £20/watt, we engineered solutions that had to work. That mentality hasn't changed.
Built for Zero-Failure Environments
Network Rail crossings. Water authority telemetry. Remote telecoms. SCADA systems. Marine installations. These aren't hobby projects—they're critical infrastructure where downtime costs money and reliability saves lives. Our systems deliver 99.9% uptime because we engineer for the conditions you actually face: salt corrosion, temperature extremes, power fluctuations, and isolation.
Precision Engineering. No Compromises.
We don't offer one-size-fits-all solutions. Our engineers work with you to build systems tailored to your exact requirements:
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Load analysis that eliminates wasted energy and voltage losses.
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High-efficiency PV arrays 30-40% smaller than conventional designs.
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Matched battery banks (LiFePO4, lead carbon, premium gel lead-acid) sized precisely for your load profile.
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Remote monitoring that catches issues before they become failures.
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Full system integration where every component works together—not just stacked together.
20+ Years of Silent, Reliable Operation
Since 1997, our systems have outperformed expectations in the harshest environments. Many exceed 20 years of continuous operation. This track record isn't luck—it's the result of engineers who understand off-grid power deeply - because we live it.