# SunStem: Solar Calculator — RV Battery Runtime & Safety

> RV Battery Runtime & Safety (iPhone/iPad app by Dmitriy Motorin.)

- Source: https://appshunter.io/ios/app/sunstem-solar-calculator/id6787007719 (this page in markdown: same URL + `.md`)
- Developer: [Dmitriy Motorin](https://appshunter.io/developer/1495533596)
- Category: Utilities
- Price: Free
- Age rating: 4+
- Requires: iOS 17.0 · 7 MB
- Languages: American English
- Released: 2026-07-09
- Data updated: 2026-07-30
- User reviews in markdown: https://appshunter.io/ios/app/sunstem-solar-calculator/id6787007719/reviews.md

## What is SunStem?

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.


## Version history (last 2 releases)

### 0.1.1 — 2026-07-16

Refined offline solar and battery planning: runtime forecasts, seven-day risk audit, build sizing, safety review and local evidence exports for iPhone and iPad.

### 0.1.0 — 2026-07-09

No release notes.

## More apps by Dmitriy Motorin

- [Minute Notes](https://appshunter.io/ios/app/minute-notes/id1495533597)
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- [Get Tan: УФ и таймер загара](https://appshunter.io/ios/app/get-tan/id1496553189)
- [Awesome Filters - Photo Editor](https://appshunter.io/ios/app/awesome-filters-photo-editor/id1499982722)
- [Weight Loss Yoga for Beginner](https://appshunter.io/ios/app/weight-loss-yoga-for-beginner/id1502548881)
- [Bunker Stem: Fuel Calculator](https://appshunter.io/ios/app/bunker-stem-fuel-calculator/id6777398984)

All apps by Dmitriy Motorin: https://appshunter.io/developer/1495533596

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-30.*