Deye SUN-35K-G04 (35 kW) - three-phase grid-tie inverter

Three trackers and nine strings in the thirty-kilowatt housing

The SUN-35K-G04 delivers 35 kW and accepts an array of up to 45.5 kW spread across three independent MPPT trackers with three strings each — nine rows of panels in total. The housing and weight are identical to the SUN-30K-G04 (item 2051) at 647.5 × 537 × 303.5 mm and 44.5 kg, so the same installation effort buys 5 kW more output and an extra tracker. Nine strings is a level of flexibility rarely seen in the domestic segment: an east slope, a west slope and a separate ground-mounted section can all be served at once, each group running at its own maximum power point. On sites with awkward layouts — a farm with several roofs, a plant with carport canopies, an estate with outbuildings — this solves the problem with one device instead of two. The inverter is grid-tie: there is no battery inside, and when grid voltage disappears it stops along with it.

Why full power is available from just 292 volts

Three trackers of 40 A give 120 A of DC together, so delivering 35 kW requires an array voltage of only about 292 V — the lowest threshold among all three-phase grid-tie models in this catalogue. The practical consequence is that short strings of eight or nine modules work here, whereas on the SUN-25K-G05 (item 2049) with its threshold near 480 V they would be hopeless. That is exactly what makes this model convenient for roofs where a long row has nowhere to go: dormer windows, chimneys, slopes of unequal length. An MPP range of 200 to 850 V with a 250 V start voltage means an early wake-up in the morning and late operation in the evening, when neighbouring models have already stopped. The 60 A short-circuit rating per tracker leaves room for three parallel strings of modern high-current modules with no current limiting.

A 45.5 kW array on a 35 kW inverter: oversizing as the norm

The array-to-rating ratio here is 1.3, and that is not marketing but the recommended working regime for Ukrainian latitudes. Panels produce their nameplate figure only at twenty-five degrees and full sun, while in reality they spend most of the year at 60–75 % of it. A thirty percent surplus compensates for precisely that gap: in winter and under cloud the system yields noticeably more, while in summer the inverter clips the peak to 35 kW for a few hours a day, sacrificing only single-digit percentages of annual yield. If you plan zero export to the grid — the only permitted mode for many commercial sites in Ukraine — oversizing becomes even more worthwhile, because it flattens the daily curve to match your own consumption. Going beyond 45.5 kW is not advisable: that exceeds the manufacturer's warranty conditions and loads the input stages beyond their design figures.

Fifty-three amps per phase: the line and the switchboard

Rated output current is 53 A per phase at 380 V and 50.7 A at 400 V, with a maximum of 58.3 A, so the line is designed around a three-phase 80 A breaker and 25 mm² copper cable. At this current voltage drop becomes a real factor: if the run from inverter to main board is thirty or forty metres, the cross-section must be calculated rather than taken from a table of minimums. The AC side uses an IP65 connector and the DC side MC4 plugs, so no separate junction box is needed beneath the inverter. Thirty-five kilowatts is already commercial territory: the private household ceiling in Ukraine is 30 kW, so the site must be registered as a company or a sole trader with a matching connection agreement. Check the permitted generation capacity in your utility contract before ordering, because that figure, not the hardware, determines how much you can actually export.

Mounting forty-four kilograms and preparing the wall

A weight of 44.5 kg with a width of almost seventy centimetres demands a load-bearing base: concrete, solid brick or a welded steel frame on footings. Two installers can lift the unit to standard height without machinery, but only with the mounting rail already fixed and checked for level. Air clearance around the case is essential — at least thirty centimetres above and to the sides, because active cooling relies on airflow rather than radiation. A protection board with a breaker and an AC surge arrester has to sit alongside, so allow at least a metre and a half of wall. Noise of up to 50 dB makes a utility room or garage a better choice than a corridor in the living part of the house.

Nine curves in monitoring: diagnosis without a ladder

Each of the nine strings reports its own current and voltage curve to the cloud over Wi-Fi, LAN, RS485 or RS232, while the 240 × 160 graphic display shows summary figures on the case itself. On a site with three groups of panels at different orientations this is the only way to tell a normal east-west difference from a genuine fault. The typical scenario: all three strings on the south tracker match, but one sits a quarter lower — the cause is local, and only that row needs inspecting. Ground fault monitoring runs continuously and registers deteriorating insulation long before it triggers an emergency shutdown. The event log preserves the reason for every stoppage, which is the decisive argument in a dispute with the utility if the inverter keeps disconnecting on grid parameter deviations.

98.7 % efficiency and the real annual loss

Peak efficiency of 98.7 % and a European weighted figure of 98 % put this unit among the best of its class, and the gap between the two numbers describes its behaviour at partial load. For a 45.5 kW array, annual generation in central Ukraine comes to roughly 47 MWh, and conversion losses at 98 % amount to around 950 kWh — less than a single megawatt-hour. MPPT efficiency above 99 % means the algorithm keeps up with fast cloud movement and does not lose the short peaks that occur dozens of times on a summer day. Night consumption below 1 W totals under ten kilowatt-hours a year, a figure ignored in any calculation. Harmonics below 3 % matter on industrial sites: a clean sine wave adds no extra heating in motors and does not upset variable-frequency drives.

How it differs from its neighbours in this catalogue

The SUN-30K-G04 (item 2051) in the identical housing has two trackers and six strings at 30 kW — it is cheaper to install only on paper, since weight and dimensions are the same. The SUN-50K-G03 (item 2072) also weighs 44.5 kg but offers four trackers and 50 kW with a 65 kW array, so where the roof area exists, jumping straight to it beats the intermediate options. The SUN-60K-G (item 2066) and SUN-80K-G (item 2069) move to a 700 × 575 mm housing at 60 kg, which means a crew and lifting gear. The smaller SUN-25K-G05 (item 2049), with four strings and a weight of 20 kg, remains the choice for a simple roof with long rows. All of these are equally helpless during an outage: if autonomy is required, look at the three-phase LP3, SM2 or HP3 hybrids and keep the grid-tie inverter for sites where only the economics matter.

Send us a site plan showing every roof plane along with your connection agreement, and we will tell you whether nine strings are genuinely needed and whether the fifty-kilowatt model in the same housing is the smarter buy.