FOX ESS KH7 - single-phase hybrid inverter 7 kW.

FOX ESS KH7 is a single-phase hybrid inverter rated at 7 kW for high-voltage LiFePO₄ batteries in the 85–480 V range. Three independent MPPT inputs, charge and discharge current 50 A, generator support. Peak efficiency 97.8%, nominal output current 30.4 A, mass 29 kg, 5-year warranty.

Three MPPT inputs in a hybrid: an uncommon combination

Most single-phase hybrids stop at two tracking channels. Three inputs are considerably rarer, and combined with a battery they give a different level of design flexibility.

Seven kilowatts is roughly seventeen or eighteen panels. On a real roof that number almost always breaks into two or three sections with differing conditions: the main slope, a secondary aspect, possibly an extension or a garage.

In a grid-tied installation, splitting into groups affects only generation. In a hybrid it works at a deeper level: an even arrival of energy across the day lets the battery fill smoothly rather than absorbing the entire volume within two or three peak hours. For the storage's service life that is markedly better.

A wide 85–480 V battery voltage range

This is among the widest ranges in its class, and it directly affects freedom of choice in storage. The inverter works with comparatively small high-voltage stacks and with full-size cabinets alike.

The practical significance: a system can start with a minimal battery configuration and grow without running into the lower or upper edge of the inverter's working range. Narrower ranges among competitors sometimes force modules to be added in pairs or in fixed sets.

A charge and discharge current of 50 amperes at high voltage means roughly 10–20 kilowatts of flow depending on the battery configuration — so charging never becomes the bottleneck for seven kilowatts of panels.

Efficiency of 97.8%

A peak efficiency of 97.8% and a European weighted figure of 97.4% are strong results for a hybrid inverter. A hybrid is more complex than a grid-tied unit: it manages bidirectional flow and supplies loads even without the grid, so holding such efficiency is technically harder.

The gap between peak and European figures is just four tenths of a per cent. That means the unit maintains high efficiency not only at an ideal operating point but across a wide load range — which is exactly how it works in a real house, where consumption changes constantly.

Technical specifications

• three independent MPPT inputs;

• battery voltage range 85–480 V, LiFePO₄ chemistry;

• charge and discharge current 50 A in both directions;

• nominal output current 30.4 A, maximum 33.5 A;

• external generator support;

• mass 29 kg, 5-year manufacturer warranty.

Twenty-nine kilograms: plan the installation in advance

This is one of the heaviest single-phase hybrids in its class. The reason usually lies in a more substantial heatsink and a power section built for sustained operation under load — mass in itself is not a drawback.

Installation does require preparation, however. The wall must be solid: brick or concrete, and for aerated concrete through-fixings are essential. The unit needs two people to lift, and it is worth thinking through in advance exactly how it will reach the bracket — at height this is not a weight you want to be balancing.

Account also for the supply requirement: a nominal current of 30.4 amperes means a connection of at least 40 amperes, all the more so since a hybrid can power loads and charge the battery at the same time.

A seven-kilowatt hybrid with a high-voltage battery is a solution for a house that must run without restrictions through outages. Send us the load schedule and the autonomy you want: we will size the battery and check whether your supply will take full power.