This SAE Recommended Practice SAE J2847-2 establishes requirements and specifications for communication between plug-in electric vehicles and the DC Off-board charger. Where relevant, this document notes, but does not formally specify, interactions between the vehicle and vehicle operator.

This applies to the off-board DC charger for conductive charging, which supplies DC current to the vehicle RESS of the electric vehicle through a SAE J1772™ Hybrid coupler or SAE J1772™ AC Level 2 type coupler on DC power lines, using the AC power lines or the pilot line for PLC communication, or dedicated communication lines.

The specification supports DC energy transfer via Forward Power Flow (FPF) from source-to-vehicle.

This is the 1st version of this document and completes step 1 effort that captures the initial objectives of the SAE task force. The intent of step 1 was to record as much information on "what we think works" and publish. The effort continues however, to step 2 that allows public review for additional comments and viewpoints, while the task force also continues additional testing and early implementation. Results of step 2 effort will then be incorporated into updates of this document and lead to a republished version.

Purpose

The primary purpose of SAE J2847-2 is to provide the communication to achieve RESS pack charging control irrespective of RESS pack variations or energy storage technology.

SAE J2847-1 identifies the functional messaging for the Plug-In Electric Vehicle (PEV) to connect to the utility for Level 1 2 AC energy transfer. This document identifies the additional messages for DC energy transfer to the PEV.

The specification supports DC energy transfer via Forward Power Flow (FPF) from grid-to-vehicle, and DC Reverse Power Flow (RPF) from vehicle-to-grid is included in SAE J2847-3.¹ DC Forward Power Flow is used to charge the vehicle's rechargeable energy storage system (RESS).

¹ In this specification, we use the terms FPF and RPF as precisely defined, and avoid the term V2G because its meaning has become ambiguous through divergent common usages.