Objective

A client was interested in developing a dual-port electric vehicle supply equipment (EVSE) for residential use within North America. The product would need to be high power in order to allow two cars to charge in tandem, cost competitive, visually appealing, and meet all safety regulations. Additionally, the product would need to have the ability to incorporate a future Wi-Fi add-on module for additional functionality.

Approach

The design was based around the ATmega328 microprocessor due to it's low cost and simplicity. Use of a heavy copper pour PCB for power distribution was bread-boarded, which would offer a significant cost savings over a more traditional terminal-based power relay approach. Upon successful breadboard testing, safety regulations were researched and a full prototype was designed and fabricated. Verification consisted of a blend of controlled testing per UL 2594:2016 and real-world EV charging. Vendor selection was performed in parallel to ensure that all critical components were certified to their respective standards.

Result

One round of bread-boarding and two rounds of prototyping were performed, resulting in a final prototype that meets all necessary safety standards including SAE J1772:2017, UL 2594:2016, and NFPA 70:2020 requirements. The prototype has successfully undergone informal UL testing, and is awaiting additional fundraising before moving towards pilot production.