PlugWatt: EV Charging Toolkit

PlugWatt is the offline field toolkit for EV charging technicians: the people who commission, maintain, and troubleshoot Level 2 stations and DC fast chargers at public networks, fleet depots, and highway corridors. Every charger is a two sided communication node. It talks down to the car over the J1772 control pilot and the CCS or NACS handshake, and up to its network backend over OCPP. Almost every field failure is one of three things: a power electronics fault, a vehicle handshake failure, or a backend problem. PlugWatt is built around helping you localize which one, fast, and then finish the paperwork before you leave the site. Everything works with zero signal. No account, no login, no ads, and no data collection. Ever. CALCULATORS WITH THE MATH SHOWN • Continuous load sizing, the 125 percent rule of NEC 625.42 • EVEMS managed demand comparison, including the 2026 exception in NEC 625.48 • Service and panel capacity checks, with and without load management • Conductor and overcurrent device sizing with temperature and conduit fill derating • Voltage drop for feeders and long DC runs • DC fast charger power, current, and session time estimates • Disconnect requirement helper and unit conversions • Every result shows the formula, the steps, and the code citation, with your choice of NEC edition from 2017 to 2026 TROUBLESHOOTING THAT LOCALIZES THE FAULT • Six guided decision trees: no charge, ground or insulation fault, contactor and precharge, thermal, connector and pilot, network and OCPP • Fault families with symptoms, likely causes, diagnosis steps, and the safe response • Manufacturer fault codes for the brands that publish them, each with what the code means and then an ordered list of what to check, most likely cause first • Brand library covering ChargePoint, ABB, Tritium, Alpitronic, Tesla and NACS, BTC Power, Kempower, and Signet • Charger anatomy from the AC input to the connector in your hand • Safety critical items render red and unmissable COMMS AND OCPP, FINALLY IN ONE PLACE • Control pilot states and duty cycle tables • The CCS and NACS handshake stage by stage, and what each stage failing means • ISO 15118 and Plug and Charge certificates in plain language • OCPP 1.6 versus 2.0.1 versus 2.1, a message quick reference, and offline authorization behavior SITE PAPERWORK, DONE ON SITE • Commissioning and site acceptance testing with the UL 2231 trip test • Preventive maintenance, LOTO and energized work permits, PPE assessment and glove log, work orders, OCPP configuration records, and JHA tailboards • Company, crew, and site profiles prefill every form • Photos and signatures captured in the field • Whole site packets export as one combined PDF and queue in the outbox until signal returns SAFETY FIRST • High voltage DC and arc flash awareness built on NFPA 70E • Lockout tagout guidance including DC link capacitor discharge • Glove certification rules per OSHA and ASTM D120 SUBSCRIPTION DETAILS The reference library and core calculators are free. PlugWatt Pro unlocks the full calculator suite, all guided trees, and the forms module: $6.99 monthly, $49.99 annually with a 7 day free trial for first time subscribers, or a one time $99.99 lifetime purchase. Payment is charged to your Apple account at confirmation of purchase, or when the free trial ends. Subscriptions renew automatically unless cancelled at least 24 hours before the current period ends; manage or cancel in your Apple account settings. Any unused portion of the free trial is forfeited when you purchase. PlugWatt is a field aid, not a substitute for the NEC, UL standards, manufacturer manuals, or the site engineered drawings. A qualified person must verify all results. Privacy Policy: https://thrasherapps.com/plugwatt/privacy.html Terms: https://thrasherapps.com/plugwatt/terms.html Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Support: https://thrasherapps.com/plugwatt/support.html