Dyness Knowledge | Application of repeater in multi-battery module communication

Introduction

In multi-battery module energy storage systems, we can often see a small green box connected between the battery and the inverter. This is the device we are going to introduce today - the repeater. So under what circumstances are repeaters generally used, and how are they used? You should have the answer after reading this article.

Repeater usage scenarios

In energy storage systems, the usage scenarios of repeaters can usually be divided into two major categories. The first category is CAN within the shield, and the second category is baud rate conversion.

Shielded CAN

Shielding CAN means shielding the CAN communication messages inside the battery, and only retains the messages communicating with the inverter. This greatly reduces the data processing of the inverter, thus improving the reliability of communication. This principle can be understood as "only the key points". In-shield CAN applications are commonly used with Solis and Schneider inverters.

Convert baud rate

When the number of parallel batteries in the energy storage system approaches or reaches the theoretical parallel limit, communication will tend to become unstable. At this time, we need to modify the battery dialing code and change the default 500K baud rate to 250K baud rate to improve communication stability. This principle can be understood as "speak slower". The function of the repeater is to convert the 250K baud rate of the battery to a 500K baud rate again to maintain communication with the inverter.

Production and use of repeaters

Repeater production

Repeater production requires the use of GCAN-206 CAN Repeater, two standard resistors, a drain wire and a standard network cable. Complete the wiring as shown in the picture above. When connecting the network cable, you need to pay attention to the corresponding relationship between the wire core and CAN_H and CAN_L. The network cable core and resistor pins should not be too long or short.

Repeater usage

When in use, the repeater power cord is connected to the dry contact of the battery host (different battery wiring positions will be different and need to be distinguished according to the definition of BMS dry contacts), and the network cable on the same side as the power cord is connected to the battery host CAN IN network port, the network cable on the other side is connected to the main inverter, so that the battery and inverter can communicate through the repeater.

Conclusion

Repeaters are used more frequently in multi-battery module systems and can effectively improve the stability of system communication. In the field environment, stable communication of up to 48 B3 units has been achieved, and its role is self-evident. I hope this article’s introduction to repeaters can help you gain something.

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