Why I Built Solar Planner

I kept seeing people in forums, Facebook groups, and at meetups designing solar systems with pen and paper. Sketching panels, tracing wires, and manually calculating wire sizes with a calculator. It was slow, error-prone, and honestly frustrating to watch. I built Solar Planner to make life a little easier for the community. A free tool that does the heavy lifting so anyone can design a safe solar system, whether it's their first or their fiftieth.

Meet the Creator

Hi, I'm Darren

I bought an old yacht with the bare basics, just a couple of batteries and not much else. I'm no solar expert, just someone who wanted to live off-grid. I spent months installing solar panels, controllers, batteries, and inverters, learning as I went and leaning heavily on the community for advice.

Solar Planner is my way of giving back to the community. That experience is what drove me to build this tool. A free tool that takes the guesswork out of solar design with automatic wire sizing, safety checks, and real components from real brands. I want it to be something the community builds together, so it delivers the most accurate, useful designs possible.

I'm still learning. There's a lot of technical data that goes into getting this right, and I've done my best with the knowledge I have. I welcome everyone's input to make Solar Planner better. If you spot something that could be improved or is incorrect and needs correcting, please let me know.

Revenue from Solar Planner goes toward building other projects that support not-for-profit foundations.

The Problem

The Frustration

Every solar build started the same way — paper, pencil, and a headache.

Sick of Drawing on Paper

Every time I designed a solar system, I'd grab graph paper, sketch out panels, batteries, controllers, and trace wires between them. It was slow, messy, and impossible to share.

Manual Calculations Were Error-Prone

Working out wire sizes, voltage drops, and safety margins by hand was tedious and easy to get wrong. One wrong calculation could mean melted wires or a fried controller.

No Free Tool Existed

I searched for a free, visual solar system design tool. Everything was either expensive commercial software, a basic spreadsheet, or a calculator that didn't show the full picture.

Safety Shouldn't Be Hard

Getting wire sizing wrong is dangerous. Undersized wires cause fires. Overvoltage destroys equipment. Safety margins should be automatic, not something you have to remember to apply.

The Solution

Solar Planner Does the Hard Work

So you can focus on building.

Free, Forever

No paywalls on core features. Design your system, get wire sizing, export your design — all free. No signup required.

Real Components

Not abstract calculators — actual panels, controllers, batteries, and inverters from real brands. Victron, Renogy, Epever, and more.

Community Driven

Built by someone who uses it. Feature requests come from real solar builders in the forum, not a product roadmap.

Open & Accessible

Works in your browser. No downloads, no installs. Mobile-friendly so you can check specs on-site.

Ready to stop drawing on paper?

Drag, drop, connect — get automatic wire sizing and safety checks.

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