9. Communication Protocols
9.1. Modbus Protocol Support
Nuvation Energy BMS implements the SunSpec battery models defined in the Modular Energy Storage
Architecture (MESA) as the top-level Modbus interface to the product. Specifically the BMS
implements the MESA Draft 3 Storage models (800 Series)
These specifications are available for download at
http://mesastandards.org/mesa-device
MESA Draft 3 is currently implemented on Nuvation Energy BMS. Be sure to
download the correct draft of the standard from the MESA website.
A system-level summary of all of the MESA standards can be found at
9.1.1. Modbus TCP
This protocol is used for communications over TCP/IP networks. A single Modbus TCP connection is
supported over port 502 for read and write access. Additionally, the Battery Control Panel supports as
many as 16 read-only Modbus TCP connections on port 11503.
9.1.2. Implemented MESA Models
The MESA standards contain a number of 'models' that can be implemented by vendors to describe a
storage device at various levels of detail. The models implemented by Nuvation Energy BMS are
described in the sections below.
Detailed register maps for all Draft 3 models are found in the document
MESA-Energy-Storage-
Information-Models_Draft_3.xlsx
found at the Nuvation Energy technical resources located at
https://www.nuvationenergy.com/technical-resources
9.1.2.1. Common Model
This model primarily contains information to identify the device (e.g. manufacturer, model, serial
number) as well as the version of software running on the device. A full description of the Common
Model can be found in the SunSpec specification bundle.
9.1.2.2. S801
This model describes an energy storage device at the highest possible level. State of charge and
overall alarm and warning states are found here. All mandatory points are implemented. The Modbus
address of this model is 40070.
9.1.2.3. S802
This model describes a battery storage device. At this level, the critical operational information
Nuvation Energy Battery Control Panel - Product Manual
Document ID: NE-PM-005
74
Rev 1.1, 2020-10-14
Curie Update 2
