Field reference for EV charging technicians. 9 entries, taken from the PlugWatt app.
Reference notes from PlugWatt, the offline field toolkit for electric vehicle charging installation and service technicians. It works with no cell signal, because the sites do not have any.
Get PlugWatt on the App StoreThe J1772 pilot is a 1 kHz square wave between plus 12 V and minus 12 V. Its DC level names the state; its duty cycle advertises available current. Every AC session and the front door of every DC session runs on it.
heading: Pilot states
heading: Duty cycle to current
heading: Field checks
International mode language for how a vehicle takes power. North American equipment maps cleanly onto it, and European built chargers report faults in these terms.
heading: The four modes
A DC session is a staged negotiation. Knowing which stage died localizes the fault faster than any other single fact.
heading: Stages in order
heading: Reading the stage from behavior
The high level language on top of the pilot. Plug and Charge signs the session with certificates so authorization is automatic; vehicle to grid rides the same protocol.
heading: Certificate chain in one breath
heading: Field diagnosis
heading: Vehicle to grid
OCPP is the charger to backend protocol. Version and profile agreement between charger and backend is a commissioning item, not an afterthought.
heading: Version comparison
heading: Field notes
The dozen messages that explain almost every log line a field tech reads, with the 1.6 names networks still speak.
heading: Charger to backend
heading: Backend to charger
heading: Common error codes in StatusNotification
The handful of settings that connect a charger to its operator. Record them at commissioning; they answer most NOC questions.
heading: The record that matters
heading: Connectivity hygiene
Well configured chargers keep serving drivers through network trouble. What that looks like is operator policy, and knowing the policy prevents wrong diagnoses.
heading: What good offline behavior looks like
heading: Diagnosis implications
The defining skill: an EV charger is a two sided communication node. Down to the car, up to the backend. Decide which side is sick before touching anything.
heading: The two sided model
heading: Ten second discrimination
Reference notes from PlugWatt, the offline field toolkit for electric vehicle charging installation and service technicians. It works with no cell signal, because the sites do not have any.
Get PlugWatt on the App StoreThese notes are a field aid, not a substitute for the governing codes, the stamped drawings, the authority having jurisdiction, or manufacturer manuals. Verify against the current documentation for your installed equipment.