BigBattery ETHOS Control Box

The BigBattery ETHOS Control Box Connects Your ETHOS Battery Modules to Your Inverter and Shows System Status at a Glance

The BigBattery ETHOS Control Box is the central hub of every ETHOS home battery system. It sits on top of a stack of ETHOS battery modules, manages communication between the modules and your inverter, and provides the main DC power connection to the inverter.

Its front LED interface shows system voltage, remaining capacity, BMS status codes and inverter communication settings, so you can check the health of your battery bank without a laptop. The Control Box is not a battery itself. It needs at least two 48V 5.12kWh ETHOS modules to form a working system, and it supports up to 16 modules.

BigBattery ETHOS Control Box Features

Front LED Interface

Check voltage, state of charge, BMS status codes and the active inverter protocol at a glance.

Inverter Communication

The Control Box talks to your inverter over CANBus or RS485 for closed-loop operation, so the inverter reads true state of charge instead of estimating from voltage.

Supports Up to 16 Modules

One Control Box manages up to 16 ETHOS modules, more than 80kWh of storage.

UL 9540 System Component

The Control Box is part of BigBattery's UL 9540 certified ETHOS system. Grid-tied closed-loop operation is certified with the EG4 18kPV, FlexBOSS18 and FlexBOSS21.

Cables and Rack Base Included

It comes with the controller-to-inverter power and comm cables and a battery rack base, so you have the core hardware to start a stack.

Real-World Applications

New ETHOS systems. Combine with two or more ETHOS modules to build a complete home battery.

Replacement or spare. Replace a damaged control box without changing your battery modules.

Off-grid and grid-tied homes. Use it with BigBattery APEX and EG4 off-grid inverters, or with certified EG4 hybrid inverters for grid-tied systems.

How It Compares to Common Alternatives

Versus batteries without a controller. Standalone batteries usually connect to the inverter one by one or through a bus bar. The Control Box gives the whole ETHOS stack one power connection and one communication link.

Is This ETHOS Control Box the Right Fit

• Batteries. At least two ETHOS 48V 5.12kWh modules, up to 16.
• Inverter. 48V inverters. UL 9540 grid-tied systems with closed-loop communication are certified with the EG4 18kPV, EG4 FlexBOSS18 and EG4 FlexBOSS21. For off-grid installations that do not require UL 9540, ETHOS communicates with all BigBattery APEX inverters and all EG4 inverters.

This may be a good fit if

• You are building an ETHOS system from individual modules
• You need a replacement ETHOS controller
• You want closed-loop communication with your inverter

Common Questions

Is the Control Box a Battery?

No. It is the controller for ETHOS modules and must be paired with at least two of them.

How Many Modules Can It Manage?

Up to 16 ETHOS modules.

Which Inverters Does It Work With?

UL 9540 grid-tied systems with closed-loop communication are certified with the EG4 18kPV, EG4 FlexBOSS18 and EG4 FlexBOSS21. For off-grid installations that do not require UL 9540, ETHOS communicates with all BigBattery APEX inverters and all EG4 inverters.

What Comes With It?

The Control Box, a battery rack base, two controller-to-inverter power cables and one controller-to-inverter comm cable.

What's Included

• 1 x BigBattery ETHOS Control Box
• 1 x ETHOS Battery Rack Base
• 2 x Controller to Inverter Power Cables (red and black, 4.9 ft)
• 1 x Controller to Inverter Comm Cable (4.9 ft)

The Hub of Your ETHOS System

The BigBattery ETHOS Control Box links your ETHOS modules to your inverter and keeps you informed with its front display. At Outbound Power, we help customers choose the right parts for their solar and battery systems. If you have questions, our team is happy to help.

BigBattery ETHOS Control Box Manual