This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
I note that the 0V connections of both VE CAN and VE Direct are directly connected to the battery negative terminal on an MPPT. Does this not cause problems when there is voltage drop in the power cables? e.g the voltage difference between two MPPT negatives is directly connected across the 0V connections in the CAN and VE Direct cables.
Does it not create a hazard if a Battery negative connection were lost from an MPPT in that the entire MPPT current would go down the RJ45 cable?
You raised a valid point.
But you can avoid that as long as you have a galvanic isolated communication.
And in the latest hardware revisions I've saw that Victron has started to migrate towards galvanic isolation for its interfaces.
Generally speaking the CAN has no need for a GND wire as it's a differential type of communication and the Victron VE.Direct interfaces are with galvanic isolation.
Whilst CAN may not need a ground, it doesn‘t cope with its data lines at Batt+ voltage, which would happen if a negative battery connection was lost.
VE direct is isolated, but being isolated at the transmit end leaves the data input to connected equipment as a big antenna in amongst all the noise of an MPPT. And the transmit current is rather too feeble for any decent length of cable.
The newer cerbos have isolated can bus.
