As 'Cousin stated here is the diagram of my unit using the ZEVA. The BMS takes it's power from the Lithium pack and not a separate power source. The ZEVA has a "Sleep" function that I use. I simply turn off the switch and the power to the BMS and monitor is shutdown while the BMS still retains it's settings.
I think this may help and if you don't understand something, ask away. In my build I think I ask about a billion questions.
