FoxESS EP6 6kWh HV energy storage

Fox ESS EP6 – High-voltage battery module

The EP6 is an LFP (lithium iron phosphate) based, high-voltage battery module used in solar storage systems in conjunction with Fox ESS hybrid inverters. A single unit provides a nominal capacity of 5.76 kWh, but up to 4 units can be connected in parallel, bringing the total system capacity to 23.04 kWh. This makes it suitable for both smaller residential and larger high-consumption properties.

What is it used for?

The EP6 is primarily designed to increase self-consumption from solar panels: it charges during the day and can be used in the evening or at night. Typical applications:

• Single-family homes with typical daily consumption of 10–20 kWh, where the owner wants to minimize grid draw
• Periodic backup needs – if supported by the inverter, part of the consumption can remain operational even during a power outage
• Expansion of a solar system with an existing Fox ESS inverter, where greater storage capacity must be planned for now

How does it work?

The EP6 is a high-voltage (HV) design – it operates at a nominal voltage of 192 V, with an operating range of 174–219 V. This means that the battery connects directly to the inverter via the HV bus; no DC/DC converter is required as an intermediate step. The result is better round-trip efficiency: the system operates with over 95% round-trip efficiency.

The 90% depth of discharge (DoD) means that of the 5.76 kWh, ~5.18 kWh is actually usable capacity—this is a stable value for LFP cells that can be maintained over the long term.

Communication between units takes place via CAN bus. The battery features a 5-LED status indicator, and the specifications include a built-in fire protection function.

Technical and System-Level Benefits

The EP6 is suitable for both indoor and outdoor installation—its IP65 rating protects against rain, dust, and moisture. Cooling is passive (natural convection), so there is no fan, no moving parts, and no noise.

In terms of installation flexibility: it can be mounted on walls or floors and fits in both orientations where other units cannot. Its dimensions are 380 × 640 × 185 mm, and it weighs 51 kg—it can be handled by one installer, but two people are recommended.

Scalability is a major design advantage: if you start with 1 module now but want to expand the system in the future, the EP6 handles this natively—no need for a new controller or rewiring, up to a maximum of 4 units.

Important to know

• Compatible only with Fox ESS HV inverters—cannot be integrated into other systems
• The recommended charging current is 15 A, with a maximum of 30 A—the inverter manages this automatically, but it’s worth considering during design
• By default, it does not charge below 0°C; there is an optional "warm-up" function that allows charging down to -25°C – if you install it in a cold environment (garage, storage room), this must be clarified in advance during system configuration

SOLARKIT review

The EP6 is a good choice if you’re planning to use a Fox ESS inverter and system scalability is important—you don’t have to start with maximum capacity right away, but you leave the door open for future expansion. Thanks to its IP65 rating and passive cooling, it’s a reliable option for outdoor or garage-installed systems.

Who we recommend it for: installers and end-users who operate or plan to install a Fox ESS hybrid system and are considering storage capacities between 6 and 23 kWh. Thanks to the LFP cells, a long cycle life can be expected, and the system requires no special maintenance.