# StoreWatt: BESS Field Toolkit — Offline BESS field toolkit > Offline BESS field toolkit (iPhone/iPad app by Chris Thrasher.) - Source: https://appshunter.io/ios/app/storewatt-bess-field-toolkit/id6788153038 (this page in markdown: same URL + `.md`) - Developer: [Chris Thrasher](https://appshunter.io/developer/1790762521) - Category: Utilities, Productivity - Price: Free with in-app purchases - Age rating: 4+ - Requires: iOS 17.6 · 3 MB - Languages: American English - Released: 2026-07-13 - Data updated: 2026-08-26 - User reviews in markdown: https://appshunter.io/ios/app/storewatt-bess-field-toolkit/id6788153038/reviews.md ## What is StoreWatt? StoreWatt is the offline field toolkit for the people who keep grid scale and large commercial battery energy storage systems running: commissioning crews and O&M technicians on standalone and solar plus storage sites. A battery is always energized. It cannot be switched off, lockout tagout cannot fully de energize it, and DC arcs do not self extinguish. StoreWatt is built around that reality: safety guidance is woven through every calculator, reference entry, decision tree, and form. Everything works with zero connectivity. All content ships inside the app; no account, no server, no signal required. BATTERY CALCULATORS (formula, worked steps, citation) * SOC windows and usable energy * State of health, capacity fade, and augmentation timing * C rate, power, energy, and duration * Round trip efficiency: delivered energy, losses, required charge * Sizing with degradation reserve, window comparison * Throughput and cycles versus warranty limits * DC conductor and OCPD checks with NEC derating tables * DC arc flash awareness, unit converter, series and parallel math CROSS VENDOR REFERENCE LIBRARY * BMS fault families, each with an ordered list of what to check, most likely cause first: cell voltage, imbalance, insulation, contactors, comms * PCS faults with the same treatment, plus EMS dispatch behavior and thermal management * Brand notes: Sungrow PowerTitan, Tesla Megapack, Fluence Gridstack, SMA, Power Electronics, EPC Power * CAN bus, Modbus RTU and TCP, RS 485, DNP3, IEC 61850 * PLC and SCADA platforms, power plant controller, ANSI device numbers * Standards summaries: NFPA 855, UL 9540 and 9540A, NEC 706 and 480, NFPA 70E, IEEE 1547, IFC GUIDED TROUBLESHOOTING Decision trees for a plant that is not dispatching, rack and module isolation, insulation faults, thermal problems, and comms failures. Safety critical findings render red with a stop work posture, never a blind reset. SITE PAPERWORK TO PDF A LOTO permit built for stranded energy, energized work permit, commissioning and acceptance records, fire and gas verification, ERP drill log, JHA tailboard, work orders, and O&M checklists. Photos, signatures, crew sign in, autofill from your profiles, whole site packet export, and an outbox that queues email until you find signal. RECEIPT TRACKER Scan a receipt in the truck: on device OCR reads the vendor, amount, date, and category, then emails a clean PDF copy to the office and to you. FREE AND PRO The reference library with search, the SOC and usable energy calculator, and the unit converter are free forever. StoreWatt Pro unlocks the full calculator suite, all ten forms with PDF export, the receipt tracker, and the guided decision trees. StoreWatt is a field aid, not a substitute for NFPA 855, UL 9540 and UL 9540A, the NEC, NFPA 70E, IEEE 1547, the IFC, manufacturer manuals, or the site PE stamped drawings and Emergency Response Plan. An ESS qualified person is required for safety critical work. SUBSCRIPTION DETAILS StoreWatt Pro is available as a monthly subscription for $14.99, an annual subscription for $119.99 with a 7 day free trial for first time subscribers, or a one time lifetime unlock for $299.99. Prices may vary by region. Subscriptions are billed to your Apple account and renew automatically until cancelled at least 24 hours before the end of the current period; manage or cancel anytime in your Apple account settings. Any unused portion of a free trial is forfeited when you purchase a subscription. Privacy Policy: https://thrasherapps.com/storewatt/privacy.html Terms of Use: https://thrasherapps.com/storewatt/terms.html Support: https://thrasherapps.com/storewatt/support.html ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | StoreWatt Pro | $6.99 | per month | | Pro Annual | $49.99 | per year | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Pro Lifetime | $99.99 | one-time | ## Version history (last 4 releases) ### 1.1.2 — 2026-08-25 EVERY FAULT NOW TELLS YOU WHAT TO CHECK, IN ORDER The BMS and PCS fault entries carried an explanation. They now carry an ordered list of what to check, most likely cause first, across all twenty two. The ordering does the diagnostic work. Cell over voltage starts with whether it is one cell or many, because that single question separates a failing cell from a calibration problem. Over temperature starts with the spread across cells, since every cell warm together is cooling or duty while one cell hot alone is a thermal event and not something to reset. AC grid window starts with correlating the timestamp across the plant, which tells you the grid did it before anyone opens a cabinet. Contactor fail to close starts with the interlocks, because the contactor is usually innocent and a precharge resistor opened by cycling is the frequent culprit. Comms faults start with restoring the link, because stale data makes healthy racks look sick and sends you to the wrong rack. Safety critical entries still lead with stop work. Insulation faults, welded contactors, short circuits and ground faults open with the isolation posture before any diagnosis, because on a battery plant the isolation question comes first. ### 1.1.1 — 2026-08-22 THE REFERENCE LIBRARY IS FREE Over ninety entries, free, offline, forever. BMS and PCS fault families, EMS and dispatch, thermal management, the brand equipment library, comms and protocols, a Modbus quick reference, controls and SCADA, protection and ANSI device numbers, standards summaries, and safety. Search by code, brand, symptom or protocol. It all ships inside the app, so it works in a container yard with no bars. FREE ACCESS CODES REDEEM IN THE APP If you have been given a code for full access, Settings takes it directly instead of sending you out to the App Store. TELL ME WHAT TO ADD NEXT Settings has an option that opens an email straight to me. If a calculation is wrong, a fault code is missing, or there is something this should do and does not, say so. Requests from working technicians set the priority. Plus a short agreement on first launch covering what the app is and is not. Accept once and it is gone. ### 1.1 — 2026-08-21 Two changes. Free access codes now redeem inside the app. If you have been given a code for full access, Settings will take it directly instead of sending you out to the App Store. And you can now tell me what to add next. Settings has a new option that opens an email straight to me. If a calculation is wrong, a fault code is missing, or there is something this should do and does not, say so. I read all of it. ### 1.0 — 2026-07-13 No release notes. ## More apps by Chris Thrasher - [DropTubeBuilder: Fuel Tanks](https://appshunter.io/ios/app/droptubebuilder-fuel-tanks/id6740597739) - [Lava Dash](https://appshunter.io/ios/app/lava-dash/id6742521742) - [StreakQuest](https://appshunter.io/ios/app/streakquest/id6743329674) - [BlockThrasher: Neon Puzzle](https://appshunter.io/ios/app/blockthrasher-neon-puzzle/id6746172717) - [TrialMate: Attorney Case Prep](https://appshunter.io/ios/app/trialmate-attorney-case-prep/id6748589882) - [Side Work Tax](https://appshunter.io/ios/app/side-work-tax/id6782625305) All apps by Chris Thrasher: https://appshunter.io/developer/1790762521 --- *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 2026-08-26.*