About DC Power Planner

1. Why We Built DC Power Planner

Extra-low-voltage DC installations (12V, 24V, and 48V) are frequently underestimated. While 12V DC does not pose the same electrocution hazard as 240V AC household mains, 12V and 24V battery systems carry far higher electrical currents for an equivalent power load. A 2,000W appliance on a 240V AC household circuit draws just 8.3 Amperes; the exact same 2,000W load inverted from a 12V LiFePO4 battery bank draws over 185 Amperes.

Before DC Power Planner, DIY builders, apprentice auto-electricians, and marine outfitters had to juggle static wire-sizing charts, PDF product manuals across a dozen manufacturers, and static drawing programs like Visio or draw.io that had zero electrical intelligence. If a user accidentally drew a 6mm² wire between a 200Ah Lithium battery and a 2,000VA inverter, or forgot to place a Class-T fuse at the positive battery post, a static drawing program would never warn them.

DC Power Planner solves this by combining a verified hardware component database, a physics-based voltage drop and ampacity engine, an automated safety rule validator, and a real-time nodal power simulator inside a zero-install web application.

2. Mathematical Models & Engineering Methodology

Every calculator and simulation output on DC Power Planner is governed by deterministic electrical engineering equations and empirical manufacturer specifications. Below are the core mathematical models used across our tools:

A. Two-Conductor DC Voltage Drop & Conductor Resistance

In any DC circuit, current flows from the positive source terminal, through the supply conductor to the load, and returns to the negative source terminal via the return conductor (or chassis earth). Our cable sizing engine computes total loop voltage drop using annealed copper resistivity adjusted for operating temperature:

• L (One-Way Length): Physical cable route distance in metres from source to load. Multiplied by 2 to account for the complete positive and negative return path.
• I (Design Current): Maximum continuous circuit current in Amperes.
• ρ_T (Copper Resistivity): 0.018 Ω·mm²/m, representing high-conductivity oxygen-free copper (0.01724 Ω·mm²/m at 20°C) derated for typical enclosed vehicle/engine-bay ambient temperatures (~35°C–45°C).
• A (Cross-Sectional Area): Standard metric copper conductor cross-section in square millimetres (1.5 mm² to 120 mm²).
• Dual Constraint Enforcement: The sizing engine evaluates both the user's maximum allowable voltage drop target (≤ 3% for voltage-sensitive inverters, fridges, and chargers; ≤ 10% for general lighting) and the continuous thermal ampacity limit of the cable insulation. It always selects the larger of the two required cross-sections.

B. Overcurrent Protection (Fuse & Circuit Breaker Sizing)

The primary purpose of a fuse or circuit breaker is to protect the cable insulation from thermal runaway and fire during a dead short or sustained overload. Our validator and calculators enforce the fundamental rule of circuit protection:

• Continuous Load Headroom (1.25×): Fuses are sized at approximately 125% to 150% of maximum continuous device current to prevent nuisance thermal fatigue blowing, rounded to standard automotive/marine ratings (5A, 7.5A, 10A, 15A, 20A, 25A, 30A, 40A, 50A, 60A, 80A, 100A, 125A, 150A, 175A, 200A, 250A, 300A, 400A).
• Interrupting Capacity (AIC) by Battery Chemistry: Lithium Iron Phosphate (LiFePO4) battery banks exhibit ultra-low internal resistance and can deliver fault currents exceeding 5,000A–10,000A into a dead short. For primary LiFePO4 battery protection and high-wattage inverters, our engine recommends Class-T fuses (20,000A AIC) or high-AIC MEGA/ANL fuses in accordance with ABYC E-11 and AS/NZS 3001.2:2022.

C. Battery Runtime, Depth of Discharge (DoD) & Peukert Derating

Usable energy in a battery bank depends heavily on electrochemistry and discharge C-rate:

• LiFePO4 (12.8V / 25.6V / 51.2V): Modelled with a safe daily Depth of Discharge of 80%–90%, coulombic charge efficiency of 98%, and flat voltage curve (k ≈ 1.02).
• AGM / Gel / Lead-Acid (12.0V / 24.0V): Modelled with a safe Depth of Discharge of 50% to prevent irreversible plate sulfation, coulombic charge efficiency of 80%–85%, and prolonged constant-voltage absorption phase tapering.

3. Industry Standards Referenced

Our automated validator rules, cable ampacity tables, and educational guides are engineered around four foundational Australian and international electrical standards for mobile, recreational vehicle, and marine installations:

Important Note: While DC Power Planner uses these standards to inform its mathematical models and validation checks, software simulation cannot inspect physical crimp quality, thermal bundling, or chassis routing. Always have your final installation inspected and certified by a licensed auto-electrician, marine electrician, or registered electrical contractor in your jurisdiction.

4. Hardware Database & Editorial Independence

Every product in the DC Power Planner Component Library (spanning Victron Energy, REDARC, Renogy, Blue Sea Systems, PowerPaul Australia, KickAss, EcoFlow, Engel, Dometic, Webasto, STEDI, and Haltech) is catalogued using official manufacturer datasheets and installation manuals.

• Verified Terminal Pinouts: Each component model includes its exact physical terminal configuration, polarity, nominal voltage rail, and metric stud or connector hardware (e.g., M6, M8, M10 threaded studs, Anderson SB50, MC4, or VE.Direct ports).
• Disambiguation from PCB Tools: DC Power Planner is built exclusively for high-current vehicle, marine, and off-grid power installations. It is completely distinct from semiconductor/PCB board-level power tree tools such as Analog Devices' LTpowerPlanner or Texas Instruments' Power Stage Designer.
• 100% Free & Client-Side Privacy: All circuit simulations, cable calculations, and JSON diagram saves execute locally inside your browser. We never sell user data or lock safety checks behind a paywall.

5. Contact Us & Hardware Submissions

We actively maintain and expand the DC Power Planner component library, calculators, and validation rules. Whether you are a component manufacturer wishing to submit official CAD/datasheet specifications, an auto-electrician with feedback on a validation rule, or a user with a technical question, we welcome your input.