Fox ESS ECS4100 4.03kWh High-Voltage Battery Module (Master) V2 Connector Type B
The Fox ESS ECM4100 (part number FE-HV-ECM-4100, supplier part number Energy Cube CM4100) is a 4.03 kWh high-voltage LiFePO₄ master battery module from the Fox ESS ECS Series. This is a Version 2 module with Connector Type B. The master module includes the system controller and is required in every ECS4100 battery stack. Each module provides 4.03 kWh, scaling up to 28.21 kWh total capacity (1 x Master + 6 x Slaves). With 90% depth of discharge, round-trip efficiency greater than 95%, and cycle life of 6,000 cycles or more, the ECS4100 Master is designed for residential and light commercial energy storage. CAN/RS485 communication, IP65 rated. Available from DECO Group, a UK-based solar wholesaler for professional trade installers.
Key Technical Details (Single Master Module)
- Part number: FE-HV-ECM-4100
- Supplier part number: Energy Cube CM4100
- Model: ECM4100 (Master)
- Version: V2.0
- Connector type: B
- Battery chemistry: LiFePO₄ (prismatic cell)
- Nominal energy: 4.03 kWh per module
- Depth of discharge: 90%
- Continuous discharge rate: 2,875 W
- Maximum discharge rate (5 minutes): 2,875 W
- Surge discharge rate (15 seconds): 2,875 W
- Maximum charge rate (5 minutes): 2,875 W
- Communication: CAN / RS485
- Display: LED x 7
- Ingress protection: IP65
- Weight: 38.25 kg
Stack Specifications (ECS4100-H2: 1 x Master + 1 x Slave)
- Nominal capacity: 8,060 Wh (8.06 kWh)
- Nominal voltage: 115.2 V
- Operating voltage: 97.2 V to 131.4 V
- Recommended discharge current: 25 A
- Maximum charge/discharge current: 50 A
- Peak discharge current: 65 A @ 30 seconds
- Round-trip efficiency: greater than 95%
- Cycle life: ≥6,000 cycles (measured at 25°C, 90% DoD, 0.5C charge/discharge)
- Scalability: Maximum 7 modules in series per stack
- Maximum stack capacity: 28.21 kWh (1 x Master + 6 x Slaves)
- Dimensions (2-module stack): 570 x 350 x 380 mm (W x H x D)
Environmental and General
- Operating temperature: -10°C to +55°C
- Storage temperature: -20°C to +55°C
- Cooling: Natural convection
- Humidity: 0% to 100% (no condensation)
- Maximum altitude: 2,000 m
- Installation: Outdoor or indoor, stand-mounted
- Ingress protection: IP65
Key Features
- 4.03 kWh per module with long-life LiFePO₄ prismatic cell chemistry
- Master module includes the system controller; one is required per stack
- 90% depth of discharge with round-trip efficiency greater than 95%
- Scalable from a minimum 2-module stack up to 7 modules (28.21 kWh)
- Cycle life of 6,000 cycles or more
- CAN/RS485 communication for system integration and monitoring
- Plug-and-play installation for fast on-site build-out
- IP65 rated for indoor or outdoor stand-mounted installation
- 12-year warranty upon registration with Fox ESS
System Compatibility
- Compatible with Fox ESS hybrid inverters and AC charger inverters
- This is the master module and is required in every ECS4100 battery stack
- Minimum configuration for H1, KH1, and H3 Smart inverters: 1 x Master + 1 x Slave (2 modules)
- Minimum configuration for H3 and H3 Pro inverters: 1 x Master + 2 x Slaves (3 modules)
- Maximum configuration: 1 x Master + 6 x Slaves (7 modules, 28.21 kWh)
- V2 Connector Type B: when upgrading an existing system, confirm it is V2 with Connector Type B before adding modules
Installation Notes
- At 38.25 kg, a two-person lift is required
- Stand-mounted stackable installation, IP65 rated for indoor or outdoor siting
- When expanding an existing stack, the connector type must match and all modules must be the same version
- Must be installed by a qualified electrician or technician in compliance with local wiring regulations
Certifications and Compliance
- IEC 62619 (Safety)
- EMC: EN IEC 61000-6-1/2/3/4
- Transportation: UN38.3
Warranty
- Standard warranty: 5 years
- Extended warranty: 12 years when the installation is registered with Fox ESS online
Common Questions
Click a question below to reveal the answer.
What is the difference between the ECS4100 Master and Slave?
The Master module (ECM4100) contains the system controller and is required in every stack. Only one Master is used per stack; additional capacity is added using Slave modules (CS4100). Both modules provide 4.03 kWh capacity. The Master has 7 LED indicators vs 1 on the Slave, and weighs 38.25 kg vs 34.8 kg.
Can the Fox ESS ECS4100 Master operate on its own?
No. The ECS4100 system requires a minimum of 2 modules (1 x Master + 1 x Slave) for H1/KH1/H3 Smart inverters, or 3 modules (1 x Master + 2 x Slaves) for H3/H3 Pro inverters.
How many ECS4100 modules can be installed in one stack?
A maximum of 7 modules per stack (1 x Master + 6 x Slaves), giving a total capacity of 28.21 kWh.
What should I check before adding ECS4100 modules to an existing stack?
Confirm the existing stack is V2 with Connector Type B. V1 and V2 batteries are not interchangeable, and connector types must match within a stack.
What is the cycle life of the Fox ESS ECS4100?
The ECS4100 is rated at 6,000 cycles or more, measured at 25°C, 90% DoD, and 0.5C charge/discharge rate.
DECO Group supplies Fox ESS ECS master and slave battery modules in both Connector Type A and Type B variants alongside compatible hybrid inverters, AC charger inverters, and system accessories. Browse our Fox ESS battery storage catalogue for complete scalable storage configurations.
About DECO Group
We supply Fox ESS high-voltage battery modules, hybrid inverters, and installation components to professional installers and electrical contractors across the UK. Our ECS range covers all capacity variants with master and slave modules in stock for flexible system sizing. Visit decogroup.co.uk for the full catalogue.
