OpenEVSEOpenEVSE provides energy monitoring architecture for Electric Vehicle Charging Stations as well as energy monitoring devices. It is a DIY kit for people wanting a charging station at home. It is one of the good ones out there, see the comparison. This device can have a Huzzah module installed to make it IP enabled.
OCPPThe goal of the Open Charge Point Protocol (OCPP) is to offer a uniform solution for the method of communication between charge point and the central system. With this protocol, it is possible to connect any central system with any charge point, regardless of the vendor. OCPP 1.6 is the most recent version released by OCA that incorporates several improvements suggested by OCA members who are working with OCPP in the field. The 1.6 version is supported by a compliance testing tool for self-testing and by a Certification Program. OCA provides OCPP. The Open Charge Alliance (OCA) is a global consortium of public and private electric vehicle (EV) infrastructure leaders that have come together to promote open standards.
Wifi ModuleHuzzah module that is based on ESP8266 is used to IP enable OpenEVSE but does not have the processing power to act as an edge computing device. So you need to choose a more powerful wifi-enabled computing module that is capable of establishing OCPP protocol with a compliant server. We used Raspberry Pi A+ for our testing. Raspberry serial ports work at 0V-3.3V while OpenEVSE supports serial TTL devices at 5V on the six-pin header. You can speak RAPI on this serial port to control or to get information from openEVSE. To connect the Raspberry Pi and OpenEVSE controller, you need a level shifter. We used a bi-directional level shifter to combine the two.
Figure 1: Raspberry Pi connected to OpenEVSE and powered by it