Most of the zero use two signal to enable or disable the battery operation with the bike. one is called " Battery Throttle Enable" or "Throttle engage" and the second one is "ON signal To BMS"
Both are comunicating the the MBB .Usually both of these signal can control the power pack use
These are ON/OFF, no data signal type.
The ON signal to BMS will activate the battery BMS wich usually control the contactor. Bike OFF = 0V sent to the BMS and bike on = V+ batt sent to the BMS... well on the 2011 model at least...
The THorttle engage signal is the signal that protect the battery to be overdisharged. Moto ON = V+ and moto OFF= 0v and also if thge BMS detect one or more cell bank discahrged to LVC, it will fall to 0v too This signal is sent from the battery to the MBB.
The battery throttle engage is a signal that come from the powerpack and that goes to the MBB.
ON some zero the contactor is inside the battery and on some it is outside. all model of 2012 and previous use contactor. The 2013 use Solid state i think.
The contactor is controlled by the MBB, not directly from the BMS. BUt the BMS have to send signal to the main bike board to to let it be able to activate the contactor.
I discovered that after hours of testing every single wires on the zero harness
Then i tried to activate a battery output by faking the mbb simple signal and it worked. Wich mean the battery is protected and can be used seperatly.
what i think is that you will have to add some diode to parallel these signal and to avoid one interfere with the other.
Doc