Sometimes the Quattro 12/3000 (v209 latest firmware) doesn't switch on via the Cerbo, this gets fixed after a reboot of the Cerbo (v3.00)
There's nothing else connected in the VE.Bus system, only a BMV connected to the Cerbo.
Most of the times it works flawless. There's no difference between full or empty batteries, I've already tried that. I've used an original VE.Bus cable for the connection.