Quick Answer
RS485 can handle the data transmission requirements of large solar systems but may not be the best choice for power requirements due to limitations on current and voltage handling.
Communication Protocol Limitations
RS485 is a popular communication protocol used in many industrial applications, but it has its limitations when it comes to power handling. The standard RS485 protocol can handle a maximum voltage of 12V and a maximum current of 1A. For larger solar systems, this can be a bottleneck, especially when considering the high currents and voltages involved in battery management systems (BMS).
Voltage and Current Handling in Large Systems
In large solar systems, the battery bank voltage can reach up to 48V or even higher, and the current can exceed 100A during charging or discharging. RS485 may not be able to handle these high currents and voltages, which can lead to signal degradation, noise, and even damage to the communication equipment.
Alternative Solutions for Large Solar Systems
For large solar systems, it’s recommended to use alternative communication protocols and equipment that can handle higher voltages and currents. Some options include MODBUS over RS485 with current-limited transceivers, or even switching to more robust protocols like Ethernet or CAN bus. Additionally, using communication equipment with built-in current limiting and surge protection can help mitigate some of the risks associated with high currents and voltages.
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