GoodWe GW8.5K-MS-G40 - single-phase grid-tied inverter 8.5 kW.

GoodWe GW8.5K-MS-G40 is a single-phase grid-tied inverter rated at 8.5 kW with three independent MPPT inputs. Nominal current 37 A, maximum output 40.7 A, peak efficiency 97.7%. Mass 19 kg, dimensions 441 × 507 × 210 mm, IP65 protection, 5-year warranty.

Forty amperes of output: what that means for the supply

A maximum output current of 40.7 amperes is the level at which a standard domestic supply ceases to be adequate. Full operation requires a connection of at least 50 amperes.

It is not only the breaker in the board that needs checking. Three things matter: the main device rating, the capacity permitted by your agreement, and the cross-section of the cable from the pole to the house. That last point most often turns out to be the bottleneck in older developments — the cable was laid for entirely different loads.

If the supply cannot cope there are two routes: increasing the connected capacity through the network operator, or moving to a three-phase connection. The second option often proves the wiser one at precisely this power level.

When to consider a three-phase inverter instead

An eight-kilowatt installation on a single phase creates noticeable imbalance in the network. All generation goes into one conductor while household consumption is usually spread across three.

If you already have a three-phase supply, in most cases it makes more sense to fit a three-phase inverter of the same rating. It distributes generation evenly, removes the imbalance question and allows consumption to be offset more precisely on each phase.

A single-phase 8.5 kW model makes sense when there is no three-phase supply and bringing one in is expensive, or when the site's configuration specifically calls for a single-phase scheme.

Three MPPT inputs for a large array

Eight and a half kilowatts is around twenty to twenty-two panels. Across such an area there are almost always sections with differing conditions: different slopes, partial shading at different hours, varying tilt angles.

Three independent groups allow those differences to be accommodated. Each works in its own optimal regime, and a local problem in one section does not affect the rest of the installation. Over a year the difference in generation compared with a single group can reach appreciable percentages.

Technical specifications

• peak efficiency 97.7%, European weighted 97.2%;

• three independent MPPT inputs, tracking accuracy above 99%;

• maximum input voltage 600 V, start-up voltage 80 V;

• output harmonic distortion below 3%;

• noise level under 30 dB, natural-convection cooling;

• operation from −25 to +60 °C, humidity to 100%, altitude to 4000 m.

Installation and protection

A mass of 19 kg and dimensions of 441 × 507 × 210 mm require a solid wall and two-person installation. Space must be left around the unit for natural convection — the inverter cools without fans, and obstructing the airflow directly affects output in hot weather.

The equipment has an integrated DC switch, Type II surge protection on both sides, earth fault monitoring, and protection against reverse polarity and short circuit. IP65 protection permits outdoor installation.

Monitoring over Wi-Fi or wired LAN through the SEMS Portal app, integration via Modbus TCP/RTU, Home Assistant support. Certification: CE, IEC 62109-1/2, IEC 62116, IEC 61727, EN 50549.

At this power level the choice between a single-phase and a three-phase solution often matters more than the choice of model. Send us your supply details — we will cost both options and show which is better value once connection costs are taken into account.