Fox ESS 4.32kWh Battery Master Module | EQ4300-M | Replaces CM4300H

Description

The Fox ESS EQ4300-M Master module is the control unit at the heart of every EQ4300 stack. It combines a 4.32kWh LiFePO₄ prismatic cell battery with the stack battery management system (BMS) and talks to your Fox ESS hybrid inverter over CAN communication. Every EQ4300 system starts with one Master, and you add EQ4300-S Slave modules to build a high-voltage stack of up to 30.24kWh. The EQ4300-M is the current replacement for the CM4300H master module from the ECS4300H range.

Designed for UK home storage, the EQ4300 is a floor-standing, plug-and-play stackable battery with 90% depth of discharge, round-trip efficiency above 95% and a cycle life of 6000 cycles or more. Rated IP65 for outdoor or indoor installation with natural convection cooling, it keeps installation quick and keeps the system quiet.

4.32kWh

Module capacity

30.24kWh

Max. stack

90%

Depth of discharge

≥6000

Cycle life

CAN

Inverter comms

IP65

Outdoor / indoor

Upgrading from an ECS4300H system?

The EQ4300 range replaces the ECS4300H battery range, and the EQ4300-M is the successor to the CM4300H master. If you already own an ECS4300H stack and want more capacity, keep your existing CM4300H master and add EQ4300-S Slave modules. Fox ESS advises checking compatibility with your original modules before ordering, and the battery warm-up function is disabled in mixed stacks.

The Master needs at least one Slave

A working EQ4300 stack is 1 Master + a minimum of 1 Slave (EQ4300-L2). Order EQ4300-S Slave modules separately to reach your target capacity, up to 6 Slaves per Master. A Master on its own will not form a system.

Key features

Built-in BMS and CAN

The Master houses the battery management system for the whole stack and links to the inverter over CAN, with 6 LED indicators on the module.

Scales to 30.24kWh

Stack up to 7 modules in series (1 Master + 6 Slaves) and grow capacity as your demand grows.

90% depth of discharge

Access 90% of rated capacity per cycle with pack round-trip efficiency above 95%.

LiFePO₄ long life

Prismatic LiFePO₄ cells rated at 6000 cycles or more (25°C, 90% DoD, 0.5C).

IP65, wide temperature range

IP65 enclosure for outdoor or indoor use, charging from 0 ~ 55°C and discharging from -10 ~ 55°C.

Plug-and-play stacking

Plug-and-play connections save installer time, and a battery warm-up function is available when the system includes both Master and Slave modules.

Recommended Fox ESS inverters

The EQ4300 Master pairs with the Fox ESS hybrid inverter range, single phase and three phase:

Fox ESS H1-G2 / AC1-G2

SINGLE PHASE | 3 ~ 6kW

Models H1-3.0, H1-3.7, H1-4.6, H1-5.0 and H1-6.0-E-G2, plus the AC-coupled AC1-G2. Supports an EQ4300 stack of 1 Master + 1 to 6 Slaves (2 to 7 modules).

Fox ESS KH / KA series

SINGLE PHASE | 7 ~ 10.5kW

The higher-power single-phase range for larger homes. Supports an EQ4300 stack of 1 Master + 1 to 6 Slaves (2 to 7 modules).

Fox ESS H3 Smart

THREE PHASE | 5 ~ 15kW

Models H3-5.0 to H3-15.0-Smart with a single battery input. Supports an EQ4300 stack of 1 Master + 1 to 6 Slaves (2 to 7 modules).

Fox ESS H3 Pro

THREE PHASE | 15 ~ 30kW

Two independent battery inputs. Each stack needs 1 Master + at least 2 Slaves (3 to 7 modules per stack), so a dual-stack system uses 2 Masters and up to 12 Slaves (14 modules).

Matching the stack to the inverter

Each stack connects to the inverter battery input over CAN through the Master module. The module count you can use depends on the inverter family, so pick the stack size from the table above, then confirm the combination against the Fox ESS inverter and battery configuration guide.

Battery power depends on stack size

Maximum charge and discharge current is 50A per stack, so the battery power you can draw depends on the number of modules and the inverter you pair them with. Check the Fox ESS configuration guide for the exact figure for your combination.

Installation and safety

Install only through a qualified electrician or MCS-registered installer in line with BS 7671 and the manufacturer manual, and notify the DNO under G98/G99 where required. Fox ESS EQ series guidance specifies 10 ~ 16mm² battery cable and a 63A battery breaker for overcurrent protection.

Specifications

Module

Model

EQ4300-M (Master)

Replaces

CM4300H master module (ECS4300H range)

Module role

Master: battery plus BMS, one per stack

Battery type

LiFePO₄ prismatic cell

Module capacity

4.32kWh

Communication

CAN

Display

6 × LED

Electrical characteristics (stack level)

Depth of discharge

90%

Battery pack round-trip efficiency

>95%

Cycle life

≥6000 cycles (25°C, 90% DoD, 0.5C charge and discharge)

Recommended discharge current

37.5A

Max. charge / discharge current

50A

Peak discharge current

65A for 60 seconds

Scalability

Max. 7 modules in series (1 Master + 6 Slaves), up to 30.24kWh

Operating conditions

Installation location

Outdoor or indoor (floor stand)

Operating temperature

Charge: 0 ~ 55°C | Discharge: -10 ~ 55°C

Charge derating

Applies between 0°C and +15°C

Storage temperature

-10 ~ 40°C

Cooling method

Natural convection

Humidity

5 ~ 95% (non-condensing)

Altitude

Max. 2,000m

Certificates and protection

Ingress protection

IP65

Safety

IEC 62619

EMC

IEC 61000-6-1/2/3/4

Transportation

UN38.3

EQ4300 stack configurations

Every configuration below uses one EQ4300-M Master plus the number of EQ4300-S Slaves shown.

Stack

Composition

Nominal capacity

Nominal voltage

Operating voltage

W × H × D (mm)

Weight

EQ4300-L2

1 Master + 1 Slave

8.64kWh

115.2 V

97.2 ~ 131.4 V

570 × 368 × 380

78.5 kg

EQ4300-L3

1 Master + 2 Slaves

12.96kWh

172.8 V

145.8 ~ 197.1 V

570 × 506 × 380

115.5 kg

EQ4300-L4

1 Master + 3 Slaves

17.28kWh

230.4 V

194.4 ~ 262.8 V

570 × 644 × 380

152.5 kg

EQ4300-L5

1 Master + 4 Slaves

21.60kWh

288 V

243 ~ 328.5 V

570 × 782 × 380

189.5 kg

EQ4300-L6

1 Master + 5 Slaves

25.92kWh

345.6 V

291.6 ~ 394.2 V

570 × 920 × 380

226.5 kg

EQ4300-L7

1 Master + 6 Slaves

30.24kWh

403.2 V

340.2 ~ 459.9 V

570 × 1058 × 380

263.5 kg

Frequently asked questions

Does the EQ4300-M replace the CM4300H master?

Yes, as a product replacement: the EQ4300 range has superseded the ECS4300H range, so the EQ4300-M is the current CM4300H master equivalent. To expand an existing ECS4300H stack, keep your CM4300H master and add EQ4300-S Slave modules, after checking compatibility with your original modules.

What does the Master do compared with a Slave?

The EQ4300-M is a battery plus the stack BMS, and it is the unit that communicates with the inverter over CAN. The EQ4300-S Slave is a battery module only that adds capacity. Each stack needs exactly one Master.

Can I buy the Master on its own?

The Master is the starting point, but a stack needs at least 1 Slave to operate (EQ4300-L2). For an H3 Pro with a three-phase system, the minimum per stack is 1 Master + 2 Slaves.

How big can an EQ4300 stack be?

Up to 7 modules in series: 1 Master + 6 Slaves, giving 30.24kWh nominal capacity. An H3 Pro has two battery inputs, so it can take two stacks, each with its own Master.

Which Fox ESS inverters work with the EQ4300?

The H1-G2 / AC1-G2, KH / KA, H3 Smart and H3 Pro ranges. Confirm the module count for your inverter against the Fox ESS configuration guide.

Can I install it outdoors?

Yes. The EQ4300 is rated IP65 for outdoor or indoor floor-standing installation, with operating temperatures of 0 ~ 55°C for charging and -10 ~ 55°C for discharging. Charge derating applies between 0°C and +15°C.

What cable and breaker does the battery need?

Fox ESS EQ series guidance specifies 10 ~ 16mm² cable and a 63A battery breaker. Always follow the manufacturer manual and BS 7671.

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