Three networks, three cable types, and connectors that physically fit ports they do not belong in. This is one of the most common sources of confusion in a Victron system, and Victron's own manual opens the topic with a caution: do not confuse the VE.Bus ports on a GX device with the Ethernet or VE.Can ports.
Here is what each network is for and how to wire it correctly.
The one-paragraph summary
VE.Direct is point to point. One cable, one device, one port. VE.Bus connects inverter/ chargers and uses RJ45. VE.Can is a CAN-bus network, also uses RJ45, and must be terminated at both ends or it will not work properly.
The RJ45 similarity is the trap. VE.Bus and VE.Can both use ordinary-looking network cable and the plugs fit either socket.
VE.Direct
Point-to-point communication for a single device.
Typical users: battery monitors such as the BMV and SmartShunt, the smaller SmartSolar and BlueSolar MPPT charge controllers, and Phoenix inverters in VE.Direct versions.
Each device needs its own cable to its own port on the GX device. There is no daisy chaining and no splitting. If you have four VE.Direct devices, you need four ports.
Buy the right shape. In a tight electrical bay, a VE.Direct cable with a right-angle connector on one end is often the difference between a cable that seats properly and one that gets bent against a wall.
One exception worth knowing. On the Inverter RS, Inverter RS Solar and Multi RS, the VE.Direct port cannot be used to connect to a GX device. Those must connect over VE.Can, and their VE.Direct port exists only for programming through a VE.Direct to USB adapter. The MPPT RS is the exception to the exception and can use either.
VE.Bus
The network for Multis, Quattros and inverters. Victron refers to all of them collectively as VE.Bus products.
Uses standard RJ45 UTP cable.
Connecting one unit: plug into either VE.Bus port on the GX device.
Connecting several: for parallel, split-phase or three-phase systems, connect the first or last unit in the chain to the GX device's VE.Bus port. The units chain to each other; the GX device joins at one end.
The warning that matters: leave unused VE.Bus ports open. Victron states explicitly that you must not insert the blue RJ45 VE.Can terminators into VE.Bus ports. They fit. They are wrong. This is the single most common wiring error in mixed systems, because the terminators arrive in the box with a VE.Can product and there is a spare RJ45 socket sitting right there.
Only one VE.Bus system can connect to the built-in ports. If you need a second, an MK3-USB interface makes it visible, with real limitations: only the directly connected system feeds the overview pages, and the MK3-USB system is not under DVCC control and follows its own internal configuration. All systems do appear in the device list and in VRM energy statistics.
Remote on/off has a generation split. On Multis, Quattros and EasySolars, the remote on/off header cannot be used together with a GX device; keep the factory wire link between the left and middle terminals and use the Safety Switch Assistant if you need a disable function. That limitation does not apply to the MultiPlus-II, Quattro-II and EasySolar-II, which support remote on/off alongside a GX device.
Firmware matters. The earliest VE.Bus firmware a Cerbo GX supports is 111. Reading the microprocessor number, the first two digits are the processor version and the last three the firmware version. Units starting 18 are not supported.
If you want Bluetooth on a VE.Bus product that does not have it, the VE.Bus Smart Dongle adds it.
VE.Can
A CAN-bus network, used by the larger MPPTs in VE.Can versions, the Lynx Shunt VE.Can, Lynx Smart BMS, Skylla-i chargers, the RS range, and CAN-bus BMS batteries.
Uses standard RJ45 UTP cable, available with straight or elbow connectors.
Terminate both ends. This is not optional and it is the reason most VE.Can problems happen. Victron's instruction is direct: terminate the VE.Can network at both ends using VE.Can terminators. A bag containing two terminators ships with every VE.Can product, and additional ones are available separately under part number ASS030700000.
A bus that is unterminated, or terminated at one end only, may appear to work and then behave erratically. If you have a VE.Can device dropping in and out, count your terminators before anything else.
Power comes from the devices. All VE.Can devices supply power to the VE.Can network, so no separate power supply is needed. Protocol converters are the exception: a VE.Bus to VE.Can interface or a BMV to VE.Can interface does not power the network. A bus made only of converters will not come up.
The Cerbo GX has two independent CAN-bus interfaces, each with two RJ45 ports. Independent means devices on one do not see devices on the other, which is what lets you run a BMS on one interface and other VE.Can equipment on the other.
One firmware note: the MPPT 150/70 needs firmware v2.00 or newer to work with a GX device.
Quick reference
| Device | Network | Cable |
|---|---|---|
| SmartShunt, BMV-70x | VE.Direct | VE.Direct cable |
| Smaller SmartSolar and BlueSolar MPPTs | VE.Direct | VE.Direct cable |
| MPPTs in VE.Can versions | VE.Can | RJ45 UTP + terminators |
| MultiPlus, Quattro, Phoenix inverters | VE.Bus | RJ45 UTP |
| Inverter RS, Multi RS | VE.Can only | RJ45 UTP + terminators |
| MPPT RS | VE.Direct or VE.Can | Either |
| Lynx Shunt VE.Can, Lynx Smart BMS | VE.Can | RJ45 UTP + terminators |
| CAN-bus BMS battery | VE.Can / BMS-Can | RJ45 UTP + terminators |
| BMV-600 series | VE.Direct | VE.Direct to BMV-60xS cable |
| DC Link Box | — | RJ12 cable |
Cables: RJ45 UTP for VE.Bus and VE.Can, RJ12 UTP where a product specifies it, and VE.Direct for everything point to point.
The four mistakes worth avoiding
- A VE.Can terminator plugged into a spare VE.Bus port. Leave unused VE.Bus ports open.
- An unterminated VE.Can bus. Two terminators, one at each end, every time.
- Trying to reach a GX device over VE.Direct on an Inverter RS or Multi RS. Those need VE.Can. The VE.Direct port there is for programming only.
- Expecting a second VE.Bus system on an MK3-USB to behave like the first. It will not be under DVCC control, and it will not feed the overview pages.
Planning the ports before you buy
Count your VE.Direct devices against the ports your GX device actually has, because each one needs a dedicated port. Where you are short, moving a device onto VE.Can, if it has a VE.Can version, is usually cheaper than adding hardware.
The Cerbo GX MK2 is the usual hub. On the MK2, the RJ45 sockets are rotated compared with the earlier version specifically to make cables easier to remove in a tight installation.
If you send us a list of the Victron devices in your system, we will tell you which network each one belongs on and what cables you need before you order. Everything ships from Upland, California.