GoodWe GW8000-ET-G2 - three-phase hybrid inverter 8 kW.

GoodWe GW8000-ET-G2 is a three-phase hybrid inverter rated at 8 kW with two MPPT inputs and a high-voltage LiFePO₄ battery at 180–600 V. Efficiency 98.2%, nominal output current 11.5 A per phase, three CAN channels, generator support. IP65, passive cooling, 5-year warranty.

Eight kilowatts of backup for a three-phase house

A hybrid inverter is mostly bought not to save on the tariff but so that the house does not stop during outages. The key figure here is therefore not annual generation but the power available in island mode.

Eight kilowatts means that during a fault it is not a 'critical group' that runs but effectively the whole house. Heating with its circulation pumps, the borehole, the water heater, refrigerators, the kitchen, lighting and appliances — all at once.

The difference in experience is fundamental. A three- or four-kilowatt system forces you to plan: switch off the oven first, then start the washing machine. Eight kilowatts removes that necessity — you learn about the outage from the news, not from the behaviour of your appliances.

Phase balance in island mode

This is the nuance rarely explained before purchase, and it surfaces only after installation. A three-phase inverter in island mode forms all three phases itself, and the load across them should be more or less even.

In a real house the distribution is seldom ideal: the kitchen is usually on one phase, the boiler room on another, the garage and outbuildings on a third. While running from the grid this does not matter, but in backup the imbalance becomes noticeable.

It is therefore worth reviewing the distribution of circuits in the consumer unit before installation. It is inexpensive work, done in a few hours, but it markedly raises the real power available in island mode.

We always draw attention to this during selection — details of exactly this kind separate a system that works as intended from one that constantly disappoints.

Technical specifications

• rated power 8 kW, apparent power 8000 VA, three phases 380/400 V;

• two MPPT inputs, tracking efficiency 99.9%;

• MPP range 200–850 V, maximum input voltage 1000 V;

• LiFePO₄ battery 180–600 V, nominal voltage 500 V;

• BMS communication: three CAN channels;

• efficiency 98.2% peak, 97.8% European weighted;

• output current 11.5 A nominal, 12.6 A maximum;

• AC voltage range 310–480 V, THD below 3%;

• IP65, passive cooling, -25 to +60 °C, up to 4000 m;

• dimensions 415 × 516 × 180 mm.

Efficiency of 98.2% and what stands behind it

A peak efficiency of 98.2% with a European weighted figure of 97.8% matches the best grid-tied inverters, and for a hybrid that is a serious achievement.

A hybrid unit is more complex: it manages bidirectional flow through the battery, holds its own grid in island mode and switches regimes constantly. Each of those functions adds elements to the power path, and every element means losses.

The gap between peak and European figures is just four tenths of a per cent. That means high efficiency is held across a wide load range rather than at one ideal point — which is exactly how the unit works in a real house.

Over a year, a one-per-cent difference in efficiency for an eight-kilowatt installation is around eighty kilowatt-hours. Not much, but it is clean saving requiring no action on your part.

The generator and the winter scenario

Generator support turns the system into three tiers: sun, battery, fuel. In winter that is not a luxury but a necessity — daylight is short and the panels often cannot keep the storage topped up.

The inverter starts the generator automatically according to state of charge and stops it once the threshold is reached. The generator runs in short sessions at high load, which is the best regime both for fuel consumption and for engine life.

Importantly, for a three-phase house the generator must be three-phase too — otherwise only part of the loads receive power. This is worth allowing for at the planning stage, not once the generator has already been bought.

Eight kilowatts is the level of backup at which an outage stops affecting daily life. Tell us about the circuit distribution in your consumer unit and your list of loads: we will calculate the battery capacity and advise how to balance the phases before installation.