Solar Setup vs SunStem

Plan your off-grid solar setup in minutes. Solar Setup Calculator turns your appliance list into a complete, sized system — solar panels, battery bank, inverter, and charge controller — with real-world cost estimates and payback time. No spreadsheets. No installer sales calls. Just answer three questions about where you live, how much power you use, and how many days of battery backup you want — and the app does the off-grid solar math using the same formulas professional installers use. WHY IT'S DIFFERENT * Off-grid solar sizing built for everyone, not just installers. Pick appliances from a built-in catalog of 30+ common loads (fridges, lights, laptops, AC units, water pumps) or type in your own watts and hours. * Real sun-hours data, not guesses. The app pulls NASA POWER satellite data for your exact location on demand, so your panel count reflects what your roof actually gets — not a generic regional average. * Real battery science. Lithium and lead-acid have very different depth-of-discharge limits and round-trip efficiency. The calculator handles both correctly so your battery bank is sized for what it can actually deliver, not what's printed on the label. * Inverter sizing that handles surge loads. Air conditioners, fridges, and pumps draw 3 to 5 times their rated wattage during startup. The app accounts for this so your inverter doesn't trip out on day one. * Cost and payback estimates. Add your local kWh price and see how many years until your solar setup pays for itself versus staying on the grid. * Save and compare. Try different configurations side-by-side — 12V vs 24V vs 48V, lithium vs lead-acid, 1 day vs 3 days of backup — and see which one wins on cost and reliability. * Export as PDF. Share your sized system with an installer or supplier as a clean, professional PDF — no spreadsheet attachments. BUILT FOR - RV and van life — calculate solar for your rig with realistic appliance assumptions - Tiny house and cabin — design a system sized for your real consumption - Backyard sheds, workshops, and outbuildings — keep your tools running without trenching mains - Backup power for grid-tied homes — size a battery bank for blackouts - Marine solar setups — the same off-grid math works on a boat FREE FOREVER - Unlimited setups and saved designs - Cloud sync across devices (optional) - Full off-grid sizing wizard - NASA POWER sun-hours refresh - Built-in solar education library PRO — ONE-TIME $6.99, LIFETIME - PDF export of your sized system - Side-by-side comparison of multiple setups No subscriptions. No ads. Pay once, keep forever. THE STORY Solar Setup Calculator was built by an off-grid enthusiast frustrated with calculators that sized panels for daytime use only and left batteries empty by midnight. The app uses the full daily kWh figure for panel sizing, accounts for system losses, and handles depth-of-discharge correctly — the same way a professional designer would. Whether you're planning a weekend cabin, going full-time off-grid, or just curious what it would take to cover your fridge with solar — Solar Setup Calculator gives you a real answer in 5 minutes. Download free, design unlimited setups, and pay once for Pro if you need the comparison view or PDF export.

SunStem is an offline solar and battery calculator for RVs, vans, boats and cabins. Build a saved system profile, then estimate battery runtime, solar yield, reserve risk and safer system sizing on iPhone or iPad. CALCULATE BATTERY RUNTIME - Compare load, solar and usable battery capacity - Forecast the next charge window and hours to the reserve floor - Work offline from a saved profile and local inputs SIZE AN OFF-GRID SYSTEM - Review battery, PV, MPPT, inverter, wire and fuse planning outputs - Check voltage drop, cold Voc and fuse-versus-wire safety gates - See assumptions and deterministic calculations from the native core AUDIT THE NEXT SEVEN DAYS - Scan daily reserve risk from saved load and solar assumptions - See what to shed, when to charge and why the risk changed - Export facts for a trip partner, installer or hardware review No cloud account is required before first value. SunStem provides planning estimates and field-review evidence, not engineering certification. It does not control chargers, inverters or BMS hardware. Background or unattended hardware monitoring is not promised in this release.