Size your off-grid solar setup — in three steps.
For off-grid homes, tiny houses, vans, cabins, and anyone planning a solar install.
Free on the App Store, Google Play, or right in your browser.
What it does
Off-grid solar is hard to size right.
Oversize the system and you pour money into panels and batteries you never use. Undersize it and you run out of power on the first run of cloudy days. Getting it right means juggling your appliances, your region's sunshine, and how much backup you actually need — and most calculators hand you a single number with no working.
What you get
- Panel wattage and the number of panels
- Battery capacity in kWh for your chosen backup
- Inverter sizing for your peak load
- Daily energy demand estimate
- System cost estimate and payback period
- Regional sun-hours, with an optional NASA POWER refresh
How it works
Three questions. One sized system.
Where
Pick your region from the manual location picker. The app pairs it with peak sun-hours for that area — no GPS, no tracking.
Power
List the appliances you'll run and how long each one runs. The app turns that into a daily kWh demand.
Backup
Choose how many cloudy days of backup you want. That sets the battery bank size for your site.
Features
Built for planning, not guessing.
Works offline
Plan your system without an internet connection. Sync later when you have signal.
Real sun data
Manual region picker plus optional NASA POWER refresh for your exact location.
PDF export Pro
Save a one-page summary you can hand to an installer or print for your project notes.
Compare setups Pro
Stack two setups side-by-side to see how a change of panels or battery affects cost and payback.
Cloud sync
Optional sign-in syncs your setups across iPhone, iPad, and Android. Free.
Tips & guides
Twenty in-app articles cover wiring, MPPT vs PWM, tilt angle, lithium vs lead-acid, and more.
Pricing
Free to use. Pro is one payment, forever.
Free
$0
- Unlimited saved setups
- Cloud sync across your devices
- Manual region picker
- NASA POWER sun-hour refresh
- All 20 in-app articles
Pro One-time, no subscription
$6.99 lifetime
- Everything in Free
- PDF export of any setup
- Side-by-side comparison view
Plan your off-grid system the right way.
Three steps to a sized panel, battery, and inverter setup — with cost and payback.
Free on the App Store, Google Play, or right in your browser.