StoreWatt: BESS Field Toolkit
Offline BESS field toolkit
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
The offline field toolkit for grid scale battery storage: calculators with worked steps, cross vendor fault families, guided troubleshooting, and site paperwork to PDF.
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: cell voltage, imbalance, insulation, contactors, comms
* PCS faults, EMS dispatch behavior, 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 $6.99, an annual subscription for $49.99 with a 7 day free trial for first time subscribers, or a one time lifetime unlock for $99.99. 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
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, Chris Thrasher, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Chris Thrasher
- Size
- 2.9 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.6 or later.
- iPhone
Requires iOS 17.6 or later. - iPad
Requires iPadOS 17.6 or later. - Mac
Requires macOS 14.6 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.3 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Pro Lifetime $99.99
- Pro Annual $49.99
- StoreWatt Pro $6.99
- Copyright
- © 2026 Chris Thrasher