FoxESS 8kW Hybrid HV 3 phase + 12kWh HV Heated energy storage bundle

FoxESS 8kW Hybrid HV 3-Phase + 12kWh HV Heated Energy Storage Package

This is a pre-configured system consisting of a FoxESS P3-8.0-SH three-phase hybrid inverter and an EP12 high-voltage (HV) heatable energy storage unit (approx. 12 kWh rated capacity). The inverter is the “brain” of the system—it manages the solar panels, the grid, the battery, and the emergency power supply. The EP12 is the battery itself: it stores energy that has been generated but not used for use in the evening and morning. The package falls into the hybrid inverter + HV battery energy storage system (BESS) category, designed for single-family homes and small business systems.

FoxESS 8kW Hybrid HV 3-Phase + 12kWh HV Heated Energy Storage Package

This is a pre-configured system consisting of a FoxESS P3-8.0-SH three-phase hybrid inverter and an EP12 high-voltage (HV) heatable energy storage unit (approx. 12 kWh rated capacity). The inverter is the “brain” of the system—it manages the solar panels, the grid, the battery, and the emergency power supply. The EP12 is the battery itself: it stores energy that has been generated but not used for use in the evening and morning. The package falls into the hybrid inverter + HV battery energy storage system (BESS) category, designed for single-family homes and small business systems.

What is it used for?

It is primarily intended for three-phase single-family homes, typically where there is a heat pump, an electric vehicle charger, or a significant simultaneous load. It is also well-suited for smaller commercial and industrial (C&I) installations—such as stores, offices, and workshops—where electricity is consumed both during the day and in the evening.

The main goal is to maximize self-consumption—instead of feeding the energy generated during the day back into the grid at a low rate, you store it and use it in the evening. It also provides emergency power supply (EPS), ensuring that designated loads continue to operate during a power outage. This is not the right choice for single-phase grids.

How does it work?

The inverter converts the direct current from the solar panels into three-phase alternating current and makes real-time decisions: it first supplies the house with the generated energy, charges the battery with the surplus, and feeds only the remainder into the grid. If there is little sunlight, it makes up for the shortfall from the storage system or the grid. In the event of a power outage, it switches to emergency mode and supplies power to critical loads via the backup circuit.

The EP12 uses high-voltage LFP (lithium iron phosphate) cells. Thanks to a 90% depth of discharge, approximately 10.4 kWh of the roughly 12 kWh capacity is actually usable, and the cycle efficiency is ≥95%—meaning very little of what you charge is lost. The term “heated” is key here: with its built-in preheating function, the battery can be charged at temperatures as low as -25 °C, ensuring reliable operation even in winter and during outdoor installation.

Technical and System-Level Benefits

The inverter features 3 independent MPP trackers, allowing you to install the solar panels on up to three separate roof planes or in different orientations, even in the presence of partial shading. The DC-side input PV power thus provides significant headroom for the 8 kW AC output. The entire system has an IP65 rating and can be installed outdoors; the 8 kW model features passive (fanless) cooling, making it virtually silent.

At the system level, the high-voltage architecture is the main advantage: higher voltage means lower current and lower losses. The EP12 can be expanded later to up to 4 units in parallel, allowing the storage capacity to scale up to 46 kWh without having to replace the inverter. It also offers robust communication capabilities (SG Ready, DRM, meter, RS485, Ethernet, FoxCloud V2.0), making it easy to integrate into energy management, heat pump control, or smart home systems.

Differences

The 8 kW model is in the mid-range of the P3-S family (5–15 kW). For an average three-phase single-family home, this is the “sweet spot”: the 5–6 kW models are designed for homes with lower energy consumption, while the 10–15 kW versions are better suited for larger commercial and industrial (C&I) systems. Furthermore, the 8 kW model features passive cooling, whereas the 12 and 15 kW models are fan-cooled.

Compared to traditional low-voltage (LV) solutions, the HV battery offers better efficiency and simpler, higher-performance scalability—which is why this inverter is specifically paired with an HV storage system.

Important to know

A single EP12 unit has a continuous charge/discharge capacity of approximately 11.5 kW (30 A), which comfortably powers the 8 kW inverter. However, if higher storage capacity or longer runtime is required, it is advisable to include additional units in the system.

A three-phase power supply is required here—this package cannot be used with a single-phase connection. A heated battery is the right choice if you’re installing the storage unit outdoors, in a cold garage, or in an unheated room; charging HV batteries without preheating typically only begins above 0 °C, which is a real limitation during Hungarian winters.

SOLARKIT Reviews

We recommend this package for three-phase single-family homes equipped with a heat pump or EV charger, where there is a genuine need for emergency power. It’s also suitable for small businesses with continuous power consumption throughout the day and evening. The 8 kW + 12 kWh ratio is well-balanced—it’s not oversized, but it does offer some reserve capacity.

It’s worth paying extra for the heated battery if the storage unit will be installed outdoors or in an unheated space; for indoor, temperature-controlled installations, this feature is less necessary. And if you expect your energy consumption to increase (due to a new car, air conditioning, or growing heat pump demand), this system is easy to plan for the long term thanks to the storage unit’s expandability up to 4 units—you won’t have to replace the inverter in a few years.