Free Power System Tools
Quick, standards-based calculators for boat, RV, and off-grid electrical system design. No signup required.
Battery Sizing Calculator
Size a battery bank by chemistry (LiFePO4, AGM, Gel, Flooded), daily load, and days of autonomy. Depth-of-discharge aware.
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Solar Sizing Calculator
Panel count, charge controller amps, and MPPT-vs-PWM recommendation from your daily Wh and local peak sun hours.
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Inverter Sizing Calculator
Off-grid / mobile inverter sizing with diversity factor and 3× motor starting surge. Accounts for induction motors (pumps, compressors).
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ABYC E-11 Wire Gauge Calculator
Wire AWG recommendation with voltage drop and fuse sizing per ABYC E-11 — the standard marine surveyors reference.
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