Illustration · 13 cells

Solar panelOver Easy Solar

Over Easy Solar OES64-EU

13 cells, bifacial, glass (dual-glass module). 64 W in the CEC list.

CEC listed · May 21, 2026UL 61730Bifacial

Power (STC)64 WCEC nameplate
Efficiency≈17.8%calculated from area
%/°C Pmax−0.258CEC listing test
PTC / STC95.2%PTC 61 W (CEC)

Electrical ratings (STC)

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

Model	Pmax	Voc, V	Isc, A	Vmp, V	Imp, A	Efficiency	PTC	CEC listed
OES64-EU	64 W	9.75	8.04	8.24	7.74	≈17.8%	61 W	May 21, 2026

≈ efficiency = Pmax ÷ CEC-listed area 0.36 m².

Build & dimensions

CEC PV Module List (Oct 7, 2026)

Module area0.36 m² (3.9 ft²)CEC-listed area
Cells13 cells
Back coverGlass (dual-glass module)

Heat & cold behaviour

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

	CEC listing test
Pmax coefficient γ	−0.258 %/°C
Voc coefficient β	−0.237 %/°C
Isc coefficient α	+0.053 %/°C
Operating cell temperature	NOCT 43.6 °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
64 W	50.5 W	7.8 V × 6.48 A	12.9 W	101%

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

Certifications

CEC PV Module List (Oct 7, 2026)

UL 61730IEC 61215

UL 61730CEC listing
IEC 61215design qualification on file with CEC · Sep 25, 2025

Inverter compatibility & string sizing

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · NLR PVWatts v8

CityColdest air, °CHottest cell, °C

10.3 V

Voc when cold

per panel

7 V

Vmp when hot

per panel

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.

Microinverter tables are not shown for panels under 200 W.

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	107	11,692	6.08
Palmdale	1,835	117	12,801	6.69
Chula Vista	1,696	109	11,831	6.11
Huntington Beach	1,643	105	11,462	5.89
Riverside	1,696	109	11,831	6.21
Santa Clarita	1,724	110	12,027	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.

Questions & answers

How efficient is the Over Easy Solar OES64-EU?

Calculated from the panel area (0.36 m²): about 17.8% for the 64 W class. 64 W over 0.36 m² equals about 178 W per square meter.

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

PVWatts v8 with typical-year weather gives about 107 kWh per year per 64 W panel in Los Angeles and about 117 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.258 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 13.4% below the STC rating.

Is it bifacial?

Yes. Rear gain depends on mounting height and ground reflectance.

Sources

California Energy Commission — Solar Equipment Lists, PV Module List (snapshot Oct 7, 2026).
NLR (formerly NREL) — System Advisor Model CEC module 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.
Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).