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Boat Solar Panel Calculator

Marine-grade solar for sailboats, powerboats & liveaboards

✓ Free estimate, no signup required

Marine solar keeps your boat's 12V or 24V house bank charged while at anchor, on a mooring, or underway. Most boats run on 100–400W of solar — enough to maintain batteries, run navigation electronics, power an anchor light overnight, and run a refrigeration compressor. Liveaboards or bluewater cruisers often install 400–800W. Marine panels must be corrosion-resistant, low-profile, and able to handle constant UV exposure.

Calculator pre-loaded with typical boat & marine solar defaults — adjust for your actual usage

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Key Considerations for Boat & Marine Solar

  • ✓Flexible or semi-flexible panels work well on curved cabin tops; rigid panels suit arches and biminis
  • ✓Saltwater environment requires marine-rated connectors, tinned wire, and corrosion-protected hardware
  • ✓MPPT charge controllers are preferred for marine use — more efficient in variable cloud/angle conditions
  • ✓Lithium (LFP) house banks are increasingly popular on boats: lighter, more cycles, greater depth of discharge
  • ✓AGM batteries are cheaper and still common but require more careful charging management

Boat & Marine Solar Solar — Frequently Asked Questions

How many solar panels does a sailboat need?▾
A weekend sailor who plugs in at the marina mostly needs just 100–200W to maintain the battery while away. A coastal cruiser anchoring 3–5 nights/week needs 200–400W. A bluewater liveaboard with full refrigeration, autopilot, watermaker, and lights typically needs 400–800W or more. Enter your estimated daily kWh use in the calculator above (×30 for monthly) to get a panel estimate.
What type of solar panels work best on a boat?▾
For arches and biminis: rigid monocrystalline panels (390–430W) offer the best watts-per-dollar. For curved surfaces like cabin tops: flexible or semi-flexible panels (100–200W) work better but are less efficient and have shorter lifespans. Glass-free panels (like SunPower flexible or Solbian) are premium options with excellent durability in marine environments.
Can boat solar run a marine refrigerator?▾
Yes — this is the most common marine solar application. A 12V Isotherm or Vitrifrigo compressor fridge draws 30–50Ah/day in warm conditions. A 200W solar panel in a sunny anchorage produces roughly 60–80Ah/day, comfortably covering the fridge plus charging devices. In cloudy climates, 300–400W provides better margin.
Do I need a charge controller for boat solar?▾
Absolutely — never connect solar panels directly to a battery bank. A charge controller prevents overcharging, extends battery life, and manages the charging profile for your battery type (flooded, AGM, or lithium). Victron SmartSolar MPPT controllers are the gold standard for marine use, with Bluetooth monitoring and compatibility with LFP batteries.
Is marine solar worth it for a boat that stays at the marina?▾
Even for marina boats, solar reduces shore power consumption (and marina fees), keeps the battery maintained without leaving shore power plugged in, and gives peace of mind when the boat is unattended. A 100–200W panel ($200–$400) with a simple MPPT controller ($100–$200) is usually worth it for any boat with a house bank larger than 100Ah.

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→How Many Solar Panels Do I Need?→How Solar Panel Calculators Work→Main Solar Panel Calculator

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Disclaimer: This is an estimate for planning purposes only. Actual solar system size, cost, production, and savings depend on site-specific conditions. This tool does not constitute financial, engineering, or tax advice. Always consult a licensed solar installer and tax professional before purchasing. Data sources: NREL PVWatts, EIA Residential Energy Survey, EPA eGRID.