Easy Solar Sizer vs SunStem

SolarSize helps you estimate the solar panels, inverter and battery you may need for water pumps, farms, container homes, rural houses, small shops and security cameras. Choose your location and use case, get simple offline results, panel direction, tilt guidance and clear safety warnings. No login, no subscription, no internet needed.

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.