Free, drag-and-drop solar system design tool. Place real components, connect them, and get automatic wire sizing and safety validation.
No signup required. Free forever.
Features
From wire sizing to component compatibility — Solar Planner handles the engineering so you can focus on building.
Browse and place real solar panels, controllers, inverters, and batteries from brands like Victron, Renogy, and Epever.
Enter distances between components and get instant wire gauge recommendations based on current and voltage drop.
We size everything 25% bigger than needed — so if your panel produces 15A, we recommend wire and fuses rated for at least 19A. This built-in safety reserve keeps your system running cool and safe.
Real-time voltage drop calculations for every wire — color-coded green, amber, or red so you know at a glance.
Full support for 12V, 24V, and 48V systems with connection-specific limits for panels, batteries, and inverters.
Automatic checks that your panel Voc won't fry your controller, your battery matches your inverter, and more.
We'll email you a one-page solar sizing reference card — free.
No spam. Unsubscribe in one click.
Why Solar Planner
Tired of drawing solar systems on paper and calculating wire sizes by hand? Solar Planner was built to replace the graph paper, the calculator, and the guesswork.
Real Products
Browse a curated catalog of panels, controllers, inverters, and batteries from trusted brands. No abstract calculators — real products with real specifications.
Victron, Renogy, Rich Solar & more
Epever, Victron, and other trusted brands
LiFePO4, AGM, and gel batteries
Start with a blank canvas or choose a template. Add components, connect them, and get instant safety feedback.