Illustration · 108 half-cut cells

Solar panelVSUN (Vietnam Sunergy)

VSUN (Vietnam Sunergy) VSUN400-108MH

Name: VSUN (Vietnam Sunergy) VSUN400-108MH
Brand: VSUN (Vietnam Sunergy)

108 half-cut cells. Power classes 390–410 W in the CEC list.

CEC listed · Jul 3, 2023UL 61730

Power class

Power (STC)400 WCEC nameplate
Efficiency≈20.5%calculated from area
%/°C Pmax−0.323CEC listing test
PTC / STC93.7%PTC 375 W (CEC)

Power classes

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · 5 models

Model	Pmax	Voc, V	Isc, A	Vmp, V	Imp, A	Efficiency	PTC	CEC listed
VSUN390-108MH	390 W	36.84	13.50	30.82	12.66	≈20.0%	365 W	Jul 3, 2023
VSUN395-108MH	395 W	37.03	13.59	31.00	12.75	≈20.3%	370 W	Jul 3, 2023
VSUN400-108MH	400 W	37.20	13.68	31.17	12.84	≈20.5%	375 W	Jul 3, 2023
VSUN405-108MH	405 W	37.36	13.78	31.36	12.92	≈20.8%	380 W	Jul 3, 2023
VSUN410-108MH	410 W	37.54	13.86	31.55	13.00	≈21.0%	384 W	Jul 3, 2023

≈ efficiency = Pmax ÷ CEC-listed area 1.95 m².

Build & dimensions

CEC PV Module List (Oct 7, 2026)

Module area1.95 m² (21 ft²)CEC-listed area
Cells108 half-cut cells
Back coverWhite backsheet
FrameWhite frame

Heat & cold behaviour

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation

	CEC listing test
Pmax coefficient γ	−0.323 %/°C
Voc coefficient β	−0.260 %/°C
Isc coefficient α	+0.047 %/°C
Operating cell temperature	NOCT 45.5 °C

Vmp coefficient ≈ γ − α (CEC); used only for the hot-roof voltage estimate.

Away from lab conditions — CEC listing test points

Class	Pmax at NOCT	Vmp × Imp at NOCT	Pmax at 200 W/m²	Low-light efficiency vs STC
390 W	294.5 W	29.27 V × 10.06 A	75.4 W	97%
395 W	298.3 W	29.44 V × 10.13 A	76.4 W	97%
400 W	302.1 W	29.61 V × 10.2 A	77.4 W	97%
405 W	305.8 W	29.79 V × 10.27 A	78.3 W	97%
410 W	309.6 W	29.97 V × 10.33 A	79.3 W	97%

Pmax = Vmp × Imp from the CEC listing; low-light efficiency = Pmax at 200 W/m² ÷ (20% of STC Pmax).

Independent reliability testing

Kiwa PVEL Scorecard · RETC PV Module Index

PVEL Scorecards

VSUN (Vietnam Sunergy) named Top Performer, 2021–2026

2025, 2026

RETC Overall Highest Achiever

VSUN (Vietnam Sunergy), manufacturer level

This exact series is not listed in published PVEL Top Performer tables. Results below are for the manufacturer.

RETC PV Module Index — VSUN (Vietnam Sunergy)

Year	Recognition
2024	Test Category High Achiever
2025	Overall Highest Achiever
2026	Overall Highest Achiever; High achievement in performance; High achievement in reliability; Performance discipline high achiever (Lid, PAN file, Temperature coefficient, Iam, Letid); Quality discipline high achiever (BOM verification); Reliability discipline high achiever (Damp heat, Pid, Sdml, Tc, Uvid)

Inverter compatibility & string sizing

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · NLR PVWatts v8 · inverter datasheets · NLR SAM inverter library · CEC Grid Support Inverter List (Oct 7, 2026)

CityColdest air, °CHottest cell, °CString inverter

39.4 V

Voc when cold

per panel

25.5 V

Vmp when hot

per panel

Max panels / string

max DC 600 V

Min panels / string

MPPT from 60 V

Defaults come from NLR TMY weather (coldest hour, hottest modeled cell). Code calculations (NEC 690.7) use the ASHRAE extreme annual minimum, which is usually colder — enter it above. β is the CEC-measured coefficient; NEC 690.7 calculations use the datasheet value.

String inverters most named in SoCal permits

Inverter	Max DC input	MPPT	Window source	Panels per string
Tesla 1538000-xx-y	600 V	60–480 V	datasheet	3–15
Solis (Ginlong) S6-EH1P10K-H-US	600 V	80–520 V	datasheet	4–15
Solis (Ginlong) Solis-1P7.6K-4G-US	600 V	100–500 V	datasheet	4–15
Qcells Q.VOLT H7.6SX	498 V	234–498 V	CEC test window	10–12

Microinverters (one per panel)

Microinverter	Recommended module power	Max DC input	MPPT	Voc cold / Vmp hot	Check	DC/AC
Enphase IQ8PLUS-72-2-US	235–440 W	60 V	29–45 V	39.4 / 25.5 V	⚠ Works; below MPPT at peak heat	1.38
Enphase IQ8X-80-M-US	320–540 W	79.5 V	43–60 V	39.4 / 25.5 V	✗ Not a match: module voltage below MPPT range	1.05
APsystems (Alt Power System) DS3-L	265–570 W	60 V	28–45 V	39.4 / 25.5 V	⚠ Works; below MPPT at peak heat	0.51
Enphase IQ8M-72-2-US	260–460 W	60 V	30–45 V	39.4 / 25.5 V	⚠ Works; below MPPT at peak heat	1.23
Enphase IQ8A-72-2-US	295–500 W	60 V	32–45 V	39.4 / 25.5 V	✗ Not a match: module voltage below MPPT range	1.15

Voltage check against the microinverter datasheets — confirm the pairing on the manufacturer’s module compatibility list. Rows appear only when the panel’s power is inside the microinverter’s recommended module power range.

SolarEdge and other optimizer-based systems size strings by the optimizer rules — use the manufacturer’s designer. Reference inverters: most named in SoCal permits since Oct 2024.

Expected production in Southern California

NLR PVWatts v8 · Cali-Graf calculation

PanelsCity for chartSystem size

City	kWh / kW / yr	kWh / panel / yr	kWh / system / yr	Sun, kWh/m²/day
Los Angeles	1,676	670	12,067	6.08
Palmdale	1,835	734	13,212	6.69
Chula Vista	1,696	678	12,211	6.11
Huntington Beach	1,643	657	11,830	5.89
Riverside	1,696	678	12,211	6.21
Santa Clarita	1,724	690	12,413	6.28

Estimate for comparison, not a quote: shading, roof orientation and local losses change real output. Roof mount, 20° tilt, south, 14% system losses.

Compare with similar 400 W panels

CEC PV Module List (Oct 7, 2026) · Qcells datasheet · Kiwa PVEL Scorecard · building permits

Panel	Pmax	Efficiency	γ Pmax (CEC)	Voc, V	Isc, A	PVEL (product / brand)	SoCal permits (series)
VSUN (Vietnam Sunergy) VSUN400-108MH	400 W	≈20.5%	−0.323	37.2	13.68	brand 6×	—
Qcells Q.PEAK DUO BLK ML-G10+ 400	400 W	≥20.4%	−0.362	45.3	11.14	product 2022, 2023	221
JA Solar JAM54S31-400/MR	400 W	≈21.1%	−0.329	37.07	13.79	product 2023, 2024	152
REC Group REC400AA Pure	400 W	≈22.3%	−0.256	48.8	10.25	brand 9× (2016–2025)	66

Same fields from the same sources for every row; ≈ efficiency is calculated from the listed area. Comparable series: other brands, same product group, power range covering this class.

About VSUN (Vietnam Sunergy)

CEC PV Module List (Oct 7, 2026) · Kiwa PVEL Scorecard · RETC PV Module Index · building permits

ManufacturerVSUN (Vietnam Sunergy)
Listed in CEC asVietnam Sunergy Joint Stock Company
Websitevsun-solar.com
PVEL Top Performer (manufacturer)6 Scorecards (2021–2026)
RETC PV Module Index2024, 2025, 2026
Current panel series in CEC list82

Other series by SoCal permits

VSUNxxxN-108BMH-BB · 4VSUNxxxN-108MH-BB · 3VSUNxxxN-144MH · 1VSUNxxx-108BMH · 1VSUNxxx-108M-BB · 1VSUNxxxN-108BMH

Questions & answers

How efficient is the VSUN (Vietnam Sunergy) VSUN400-108MH?

Calculated from the panel area (1.95 m²): about 20.5% for the 400 W class. 400 W over 1.95 m² equals about 205 W per square meter.

How much energy does one panel produce in Los Angeles or Palmdale?

PVWatts v8 with typical-year weather gives about 670 kWh per year per 400 W panel in Los Angeles and about 734 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.323 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 16.7% below the STC rating.

How many panels fit on one string?

With the Tesla 1538000-xx-y (max DC 600 V, MPPT from 60 V, datasheet) in Los Angeles the calculator gives 3–15 panels per string (Voc at 2 °C = 39.4 V, Vmp at 74 °C cell = 25.5 V). Final design must follow the inverter manual and NEC 690.7.

Has this panel been reliability-tested?

This exact series is not in published PVEL Top Performer tables; VSUN (Vietnam Sunergy) was named a Top Performer in 6 Scorecards (2021–2026). RETC named VSUN (Vietnam Sunergy) Overall Highest Achiever in 2025, 2026.

Sources

California Energy Commission — Solar Equipment Lists, PV Module List, Inverter List (snapshot Oct 7, 2026).
Qcells — manufacturer datasheet “Q.PEAK DUO BLK ML-G10+ ENDURING HIGH PERFORMANCE”.
Kiwa PVEL — PV Module Reliability Scorecard, Top Performer lists 2021–2026.
RETC — PV Module Index reports 2024–2026.
NLR (formerly NREL) — System Advisor Model CEC inverter library (version 2026.7.3).
NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Chula Vista, Huntington Beach, Riverside, Santa Clarita.
Inverter datasheets — APsystems (Alt Power System), Enphase, Solis (Ginlong), Tesla (manufacturer documents).
Building permits — Southern California permit portals. Equipment matched from permit descriptions.
Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).