Victron Energy BMS-CAN Type-A Cable for Victron GX Device Communication with Lithium Batteries

About the Victron BMS-CAN Type A Cable

When you connect a third-party lithium battery to a Victron system, the GX device (Cerbo GX or Ekrano GX) needs to communicate with the battery's BMS over CAN bus. The problem is that most lithium batteries put their CAN signals on different RJ45 pins than Victron expects. A standard ethernet cable plugs in fine on both ends but puts the data on the wrong pins, and the devices never talk to each other.

The Type A cable solves this by remapping the CAN bus signal pair from pins 4/5 on the battery side to pins 7/8 on the Victron GX side. That's it. It's a pin crossover in an RJ45 cable. But getting the pinout wrong (or assuming a regular patch cable will work) is one of the most common commissioning failures on DIY Victron builds with non-Victron batteries. This cable eliminates that problem entirely.

Compatible Batteries

This cable works with batteries that use the Pylontech CAN protocol (or compatible variants) with CAN signals on RJ45 pins 4/5. Confirmed compatible batteries include the SOK 48V SK48v100, EG4 48V LL-S, EG4 24V LL, EG4 12V LL, EG4 48V Wallmount, and Pytes 48V V5.

Many other lithium batteries using the Pylontech protocol will also work with this cable. Check your battery's manual for its CAN bus RJ45 pinout. If CAN H and CAN L are on pins 4 and 5, the Type A cable is the correct choice. If they're on pins 7 and 8 (matching Victron's native layout), you need a standard ethernet cable instead.

Extending the Cable

If the 15 ft cable isn't long enough for your installation, you can extend the run with a standard ethernet cable and an RJ45 coupler between the battery and the Type A cable. The standard cable moves the port closer without remapping anything, and the Type A cable handles the pin crossover at the GX end.