About this app
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.
Latest release
What’s New
Refined offline solar and battery planning: runtime forecasts, seven-day risk audit, build sizing, safety review and local evidence exports for iPhone and iPad.
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
First snapshot captured. The trend line starts after the next crawler price observation.
- First observed Aug 24, 2026 · 1:07 AM Free
Screenshots
