Fox ESS ECS4100 4.03kWh High-Voltage Battery Module (Slave) V2 Connector Type B
The Fox ESS CS4100 (part number FE-HV-ECS-4100, supplier part number Energy Cube CS4100) is a 4.03 kWh high-voltage LiFePO₄ slave battery module from the Fox ESS ECS Series. This is a Version 2 module with Connector Type B. Each slave module adds 4.03 kWh to an ECS stack, 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 is designed for residential and light commercial energy storage. CAN/RS485 communication, IP65 rated for indoor or outdoor stand-mounted installation. This is a slave module and must be installed with a compatible ECS master. Available from DECO Group, a UK-based solar wholesaler for professional trade installers.
Key Technical Details (Single Slave Module)
- Part number: FE-HV-ECS-4100
- Supplier part number: Energy Cube CS4100
- Model: CS4100 (Slave)
- 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 1
- Ingress protection: IP65
- Weight: 34.8 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)
- Weight (2-module stack): 74.3 kg
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
- 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
- This is a slave module and must be installed with a compatible ECS master to form a working 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 34.8 kg per module, a two-person lift is required
- Stand-mounted stackable installation, IP65 rated for indoor or outdoor siting
- Incorrect installation or incompatible module expansion can cause faults; always verify version and connector type before adding to an existing stack
- 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.
Can the Fox ESS ECS4100 Slave operate on its own?
No. The CS4100 is a slave module and must be installed with a compatible ECS master module to form a working stack.
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 is the minimum configuration for H3 and H3 Pro inverters?
H3 and H3 Pro inverters require a minimum of 3 modules (1 x Master + 2 x Slaves). H1, KH1, and H3 Smart inverters require a minimum of 2 modules (1 x Master + 1 x Slave).
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 are a UK-based solar and energy storage wholesaler supplying high-voltage battery modules, hybrid inverters, and installation components to professional installers and electrical contractors. Our Fox ESS 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.
