How to Configure Master-Slave Communication Between Batteries

August 29,2025

In multi-battery systems—especially when batteries are connected in parallel—configuring master-slave communication allows coordinated operation and unified control across the pack. The master battery handles all external communication with the inverter, EMS, or host PC, while the slave batteries synchronize their operating states internally. This arrangement enhances overall system stability and safety.

I. What does master-slave communication accomplish?

Its primary purpose is to designate one battery as the “master” or “controller” that communicates externally (e.g., with the inverter or monitoring equipment), while the remaining batteries act as “slaves”, synchronizing key parameters such as SOC, current, and voltage. This prevents data conflicts and spurious alarms.

33% Off
ECO-WORTHY 48V 100AH Server Rack Battery 5.12kwh LiFePO4

ECO-WORTHY 48V 100Ah Server Rack Battery | 5.12kWh V3 Lithium Battery | UL1973 | UL9540A | 10-Year Warranty

$899.99
$1,299.99

(43 ratings)

(Buy Battery Get Free Monitor & Rack)

 
Battery Communication Cable
RS232/RS485 to USB Adapt Cable for Server Rack Battery & PC Communication
RS232/RS485 to USB Adapt Cable for Server Rack Battery & PC Communication
RS232/RS485 to USB Adapt Cable for Server Rack Battery & PC Communication
RS232/RS485 to USB Adapt Cable for Server Rack Battery & PC Communication

RS232/RS485 to USB Adapt Cable for Server Rack Battery & PC Communication

$15.99
Battery Communication Cable

Typical use cases

Parallel connection of multiple battery modules
Title

Integration with closed-loop inverters (e.g., Growatt, Deye)
Title

EMS platforms that require a unified SOC report
Title
Title

Subscribe

Get an Exclusive $10 Off Your First Purchase

Thanks for contacting us. We'll get back to you as soon as possible.

Main Article

Decoding the Multi-Dimensional Communication Capabilities of the ECO-WORTHY 48V100Ah Server Rack Battery

May 29,2025

Related Articles

How to Use the Host PC Software

September 8,2025
Title

How to Connect the Mobile App

September 11,2025
Title

Which inverter brands are supported? What is closed-loop communication?

September 19,2025
Title

How to Configure the Battery for Closed-Loop Communication with an Inverter?

September 19,2025
Title

Closed-Loop vs. Open-Loop Communication

September 22,2025

Core Topic

The core theme of this article series is “Intelligent Battery Communication,” focusing on the communication functions and technologies of the 48V 100AH server rack battery and its related devices. It covers master-slave communication, upper computer communication, mobile APP communication, and inverter communication, aiming to help users understand and apply these technologies.

II. Setting Up Master-Slave Communication

1.

Master-slave communication is currently supported on the Server Rack series batteries (48V 100 Ah and 48V 50 Ah).

Use the supplied RS485 cable to daisy-chain the RS485-2 ports between batteries

RS232 to USB 

RS485 to USB

The RS232 to USB cable is primarily used to connect devices with an RS232 interface to those with a USB interface . It can convert signal levels and communication protocols, allowing these two different types of interfaces to be compatible.

 

The RS485 to USB communication cable is a device for interface conversion. It can convert data from the RS485 protocol to the USB protocol, and vice versa. In this way, a computer can communicate with devices that support the RS485 protocol, such as  48V(51.2V) 100AH Lithium Iron Phosphate (LiFePO4) server rack battery, via the USB interface. This allows for operations like connecting to a host computer or SolarAssistant, reading battery data, and updating battery firmware.

2.

Address assignment via DIP switch

Master battery address is set as 1

Slave batteries addresses are assigned sequentially from 2 to 32

3.

If communication with the AIO is required, select the correct protocol in Mobile App, Host PC software and External display ESM-100 .

Once the addresses are configured and the wiring is complete, individual battery data can be viewed through the App, host PC software, or ESM-100 display.

III. Common Issues & Solutions

Q: The slave unit is not recognized / battery details cannot be viewed

A: Address conflict or improper wiring. Please verify the DIP-switch address of each battery and confirm that the RS485 cables are connected in the correct daisy-chain order.

Q: Data between batteries is out of sync

A: Cell imbalance or cable interference. Please inspect the RS485 cables for damage and ensure all batteries have undergone simultaneous charge/discharge cycles.

……

…

Master-slave communication is a critical step in building a highly stable battery system. Proper configuration not only enables coordinated operation among batteries, but also lays the groundwork for subsequent closed-loop control and seamless integration with host PCs and mobile apps.

Title

Related Products