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Resun Solar Brand review

RS6I-390M

390 Wp Monocrystalline
ComparePV verdict

Middle of its segment, modest efficiency

Rank 12,341 of 14,005
Compare panels Datasheet PDF
Power (Wp)
390
Weak · bottom 20%
Efficiency (%)
19.38
Weak · bottom 12%
Density (Wp/m²)
193.8
Weak · bottom 13%
Temp (%/°C)
-0.340
Typical · median -0.300
Weight (kg)
22.5
Weak · bottom 22%
Warranty (yrs)
30
Typical · median 30 yrs

The RS6I-M series from Resun Solar consists of monocrystalline modules built on half-cut cell technology paired with a 9-busbar metallization grid, addressing one of the most common issues in PV installations: power loss caused by cell microcracks and partial shading. Splitting the cells in half and increasing the busbar count reduces internal current losses within the module and minimizes the risk of hot-spot formation, resulting in higher and more stable energy output under real-world operating conditions. The panels stand out for their high resistance to PID, which limits power degradation over time and keeps the levelized cost of energy (LCOE) lower throughout the module's service life. The use of tempered glass with high light transmittance delivers solid low-light performance, while certified resistance to salt mist and ammonia makes the series suitable for both rooftop installations and large-scale PV farms in harsh environmental conditions. An additional advantage is the high mechanical strength of the frame against wind and snow loads, improving installation safety. The RS6I-M series is a good fit for investors looking for proven, reliable technology at a reasonable budget, without having to reach for premium TOPCon or HJT solutions.

Ranking

6,208 panels in the 290-490 W band, all technologies
Metric This panel Median Position in segment Overall rank
Module efficiency 19.38% 21.26% Weak · bottom 12% 12,769
Power density 193.8 212.5 Weak · bottom 13% 12,738
Temperature coefficient -0.340 -0.300 Typical 8,778
Weight per kWp 57.7 53.3 Weak · bottom 22% 11,364
Performance warranty 30 yrs 30 yrs Typical 21
Colour key Strong - top 25% Typical - middle 50% Weak - bottom 25%

Signals from the data

0 positive · 3 caution
Best for

Residential, commercial and shaded-installations.

Not ideal for

Tight roof space, roofs where every square metre has to count and weight-limited structures.

Watch-outs
19.38% module efficiency

Bottom 12% of the 290-490 W band, against a median of 21.26%.

193.8 watts per square metre

Bottom 13% of the 290-490 W band, against a median of 212.5.

57.7 kg per kWp

Bottom 22% of the 290-490 W band, against a median of 53.3.

Notes from the database
  • At 19.4% efficiency, this panel is 2.4pp below the database median of 21.8%
  • Power density of 193.8 W/m² is 24.3 W/m² below database median (218.1 W/m²) - needs more roof space
  • Temperature coefficient of -0.34%/°C is 0.04pp worse than database median (-0.30%/°C) - higher losses in summer heat
  • At 22.5 kg, this panel is 4.0 kg lighter than database median (26.5 kg) - easier handling during installation
  • #12769 for efficiency, #8778 for temperature performance out of 14005 panels

Specifications

Open datasheet PDF
Nominal power (Pmax) 390 Wp Nameplate at 1000 W/m², 25 °C
Module efficiency 19.38 % Weak Segment median 21.26%
Vmpp · Impp 39.70 V · 9.82 A Operating point at max power
Voc · Isc 49.00 V · 10.15 A Sizes the string length
Max system voltage 1500 V Longer strings than 1000 V modules
Dimensions 2008×1002×35 mm · 2.01 m² of roof
Weight 22.5 kg Weak Weak · bottom 22%
Cells 144 Monocrystalline
Coefficient Pmax -0.340 %/°C Typical median -0.300 of its segment
Coefficient Voc · Isc -0.320 · 0.050 %/°C
NOCT 45 °C At 800 W/m², 20 °C ambient
Product warranty 12 years Hardware defects only
Performance warranty 30 years Typical median 30 yrs · median 30 yrs
Degradation 0.50 % Per year after the first

Simulations

Live - change any input
Lifetime output & value
30 years at 1200 kWh/kWp/year and €0.50 per kWh
Power in year 30
-
Lifetime energy
-
Energy value
-

Degradation from this panel's own datasheet figures. No inverter, soiling or shading losses.

Heat losses
-0.340 %/°C against a segment median of -0.300
-

Alternatives

All Resun Solar panels
Filter these
Size
Panel Power Eff. Temp. Weight Difference
Resun Solar RS6I-390M 390 W 19.38% -0.340 22.5 kg You are here
LX-440M/182-108+GG 440 W 23.07% -0.240 23.6 kg +50 W, cooler, +3.7 pp
GKA210M340W 340 W 23.00% - 16.2 kg -50 W, lighter, +3.6 pp
GKA210M360W 360 W 23.00% - 16.2 kg -30 W, lighter, +3.6 pp
GKA210M380W (1/4*4*38) 380 W 23.00% - 17.1 kg -10 W, lighter, +3.6 pp
GKA210M400W (1/2*4*20) 400 W 23.00% - 18.0 kg +10 W, lighter, +3.6 pp
GKA210M400W (1/4*4*40) 400 W 23.00% - 18.0 kg +10 W, lighter, +3.6 pp
GKA210M380W (1/2*4*19) 380 W 23.00% - 17.1 kg -10 W, lighter, +3.6 pp
JT440SYK(B) 440 W 22.90% -0.240 23.0 kg +50 W, cooler, +3.5 pp
RS6I-395M 395 W 19.63% -0.340 22.5 kg +0.2 pp
RS6I-400M 400 W 19.88% -0.340 22.5 kg +10 W, +0.5 pp
RS6I-405M 405 W 20.13% -0.340 22.5 kg +15 W, +0.8 pp
RS6I-410M 410 W 20.38% -0.340 22.5 kg +20 W, +1.0 pp
RS6I-415M 415 W 20.63% -0.340 22.5 kg +25 W, +1.2 pp
RS6I-420M 420 W 20.87% -0.340 22.5 kg +30 W, +1.5 pp
SPR-MAX7-475 475 W 24.00% -0.270 21.1 kg +85 W, +4.6 pp, +10 yr warranty
SPR-MAX7-470 470 W 23.70% -0.270 21.1 kg +80 W, +4.3 pp, +10 yr warranty

Found 135 panels of the same or similar size to this one, within ±10 mm. See them here Found 206 panels of the same or similar size to this one, within ±25 mm. See them here Found 318 panels of the same or similar size to this one, within ±50 mm. See them here Found 791 panels of the same or similar size to this one, within ±100 mm. See them here

Common questions

6 answered
Is the Resun Solar RS6I-M series still available for purchase?
The RS6I-M series has been discontinued by Resun Solar and replaced by newer models. It can currently be purchased only from remaining distributor stock, while supplies last. It's worth checking current availability with a seller, since once existing batches sell out, no further units will be produced.
What warranty comes with Resun Solar RS6I-M panels?
The manufacturer provides a 12-year product warranty covering material and workmanship defects, plus a 30-year linear power output warranty. This means the module should retain a guaranteed minimum generation level even after many years of use, giving installers and owners a predictable return on investment.
How does half-cut technology in the RS6I-M differ from standard full-size cells?
Half-cut technology splits cells in half, reducing internal current losses and resistance within the module. This helps the RS6I-M handle partial shading better - covering half a cell string doesn't knock out the entire row from production, unlike older full-cell designs. The 9-busbar metallization grid further reduces microcrack risk and improves long-term power stability.
Are RS6I-M panels suitable for harsh environments, such as coastal installations?
Yes, the RS6I-M series is certified for resistance to salt mist and ammonia corrosion, making it suitable for coastal installations and agricultural sites exposed to nitrogen compounds. High PID resistance further limits power degradation caused by leakage current, which is common in humid and salty environments.
What is the maximum power output of the RS6I-M, and is that competitive for a monocrystalline panel?
RS6I-M modules reach up to 420 Wp of maximum power. This is a solid result within the standard monocrystalline PERC half-cut segment, though lower than the latest TOPCon or HJT modules. For a typical rooftop installation, this offers a good power-to-area ratio at a reasonable purchase price.
Is it worth choosing RS6I-M over more expensive TOPCon or HJT panels?
RS6I-M is a proven, budget-conscious choice for investors who want reliability without paying premium prices - its high PID resistance and solid power warranty ensure stable performance over the years. TOPCon or HJT panels offer higher efficiency and better high-temperature performance, but at a higher cost. RS6I-M is a good fit where investment cost matters more than maximum output per square meter.
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