J1772 Charger Control

J1772 Settings

The Orion BMS now supports direct (native) integration with J1772 compatible charging stations. This means that even if the onboard vehicle charger itself does not support the popular SAE standard, the vehicle can still take full advantage of this through the BMS.

There are two components to J1772 charging: the Proximity Detect signal and the Control Pilot signal. The BMS will read and interpret both of these signals in accordance with the protocol outlined by SAE in order to determine how much power the onboard charger is allowed to use as well as whether the vehicle is actively plugged in or not.

The Orion BMS also offers advanced J1772 features, such as the ability to intelligently derate the DC output current limit for the charger based on the published AC current limit from the charging station, as well as the ability to turn off the charging station if a critical fault is detected.

These settings deal with the configuration of the SAE J1772 Charger Control interface on the Orion BMS.

Enable J1772 Interface: This option will configure the BMS to dedicate the Multi-Purpose Input 1 (MPI1) to function as the J1772 Control Pilot signal and the Multi-Purpose Input 2 (MPI2) to function as the J1772 Proximity Detect signal.

Derate DC limit based on J1772 AC current limit: This option allows the BMS to reduce the DC current limit being sent to the charger (via CANBUS) based on the measured AC current limit sent from the charging station. This is a very useful feature since most AC chargers do not provide the ability to limit the AC input current, only the DC output current.

AC Charger Efficiency (AC to DC) [%]: The BMS uses this value to determine the relationship between AC input current and DC output current for the charger. This value must be filled in for the Derate DC limit based on J1772 AC current limit option to work.

Default AC Voltage: Most chargers do not send the measured AC voltage to the BMS (J1772 does not have any way to communicate AC voltage via the pilot or proximity signals, as it is assumed that the charger will be directly connected to the AC mains voltage and can measure it directly). As a result, the BMS must assume a set AC voltage to use in the event that it does not know what it actually is. The BMS will use this value to compute power and DC current limits in this instance.

Turn Off J1772 Charging If Relay Fault Occurs: Since the BMS requires a secondary control method for the charger, an inline relay is often used to fulfill this requirement. When using J1772 charging however, the EVSE itself can act as this secondary cutoff method (such that if the primary shutoff method fails to turn the charger off, the secondary method will still protect the battey pack). A critical enforcement fault (such as current still entering the pack despite charge being prohibited) will turn the EVSE off if this option is enabled.

Turn off J1772 EVSE if charging complete: By default, the BMS will keep the EVSE powered up and running whenever the inlet plug is inserted (it is assumed that the J1772 interface may be providing power to the vehicle to charge the onboard battery, or powering the BMS via an AC/DC adapter). This option allows the BMS to turn off the EVSE after the charging of the battery pack has completed.