Among the best - PV Magazine

Applications & Installations
Among the best
PV+Test: IBC Solar has now subjected its products to the challenges of the testing
program of TÜV Rheinland and Solarpraxis. The 240 watt monocrystalline module
performed very well in the TÜV chambers.
Photo: TÜV Rheinland
The new solar simulator at TÜV Rheinland: measuring the performance of modules under standard test conditions.
A crushing vice, a jolt of electricity, blinding
light, high humidity, and merciless
temperatures between -40°C and more
than 80°C – for solar modules, the laboratories
at TÜV Rheinland are more
like a modern torture chamber. The testing
procedure has pushed some modules
Test: IBC Monosol 240 ET
IBC Solar’s Monosol 240 ET is available in five different
performance classes; from 230 to 250 watts. The module
contains 60 Bosch solar cells and is built for IBC Solar by Solarwatt
in Dresden. IBC controls the quality of the modules
according to its own standard through regular audits and
quality control inspection. According to the manufacturer,
the modules are ideally suited for use on single-family
homes whose owners care about the good looks and
efficient use of their roofs. They are also installed on commercial
buildings and industrial roofs.
The module has been on the market since 2007 and is now
certified for all of the European markets. Since it began
selling them, IBC says that it has sold some 300,000 units
of this module type. Hollow chamber aluminum frames
ensure the stability of the panels. Their resistance to ammonia
and saltwater makes the modules well-suited for use
in agricultural or coastal applications.
past their limits. But the ones who make
it through are among the best of the best.
With 89.8 total points and an overall rating
of “good +”, the IBC Monosol 240 ET
is now a member of that class.
As can be expected from a module with
a “good +” rating, there was not much
Photo: IBC Solar
to complain about. To the contrary, all
five of the modules purchased by mystery
shoppers on the open market far exceeded
the performance data provided by
the manufacturer – by an average of 1.2
watts. This attested to the manufacturer’s
positive sorting claim. The module
is also very well made. The TÜV testers
searched in vain for sharp edges, foreign
material inclusions or bubbles. An examination
using electroluminescence imagery
found no faults either.
The load tests too were uneventful for
the most part. The testing regime includes
a thermal cycling test, two damp
heat tests, and two mechanical load tests,
parts of which far exceed the standards
for PV modules. After testing, the IBC
Monosol 240 ET panels that underwent
the tests showed no significant outward
signs of damage. In only one case, a few
bubbles formed on the product label of
one of the modules. The relative performance
degradation after testing was also
rather slight. The greatest damage was apparent
after the first mechanical load test
with 2,400 pascals. After that test, relative
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04 / 2012 | www.pv-magazine.com

Applications & Installations
performance degradation was measured
at a mere -0.81 percent. Many of the other
modules previously tested at the facility
showed a higher degree of performance
degradation. In the worst case, following
a mechanical load of 2,400 pascals, one
of these other modules dropped 4.3 percentage
points.
Low resistance
A few small faults had to be overcome,
however. One of the areas where the module
lost points was insulation resistance.
The initial value of 23 gigaohms square
meter was not bad, but after the 1000 hour
damp heat test, the value plummeted to
200 megaohms square meter (MΩ∙m²).
Because the final value was more than
50 percent lower than the initial measurement,
the module was docked three
points. An insulation resistance of 200
MΩ∙m² is still acceptable according to the
requirements of the product standard,
which stipulates a limit of 40 MΩ∙m².
That is the minimum requirement, however.
PV+Test sets the bar higher.
Andreas Cox, who is responsible for
photovoltaic module qualification and
for PV+Test at TÜV Rheinland, explains
why: “While evaluating PV systems, we
found cases where central inverters sometimes
shut themselves down as a result of
low insulation resistance.”
That can happen, for instance, when
modules with a low insulation resistance
are exposed to dew in the morning. When
that happens, the weakest module in the
string determines what happens next. “If
the insulation resistance of the modules
PV+Test: List of the best modules
Scoring system – Modules tested: 13
drops dramatically as a result of exposure
to moisture, as we simulate in the
damp heat test, it is taken into account
in the evaluation,” Cox explains, “Even if
the absolute value still meets the requirements
of the standard and despite the fact
that the effect can be reversible.”
Reduced insulation values following
the damp heat test are nothing new for
the TÜV testers. The standard specifies
a measurement window of two to four
Ranking Points Score Manufacturer Module type
1 94.3 excellent Solon Solon Blue 230/07-235W
2 91.3 excellent (-) Schott Solar Schott Poly 290
3 90.7 excellent (-) Sharp NU-180E1
4 89.8 good (+) IBC Solar IBC Monosol 240 ET
5 89 good (+) Mitsubishi Electric PV-TD185MF5
6 88.1 good (+) Conergy PowerPlus 225P
7 84.3 good Sovello SV-X-195-fa1
8 80 good (-) Perfect Solar PS230-6P-TOP
excellent excellent (-) good (+) good good (-) satisfactory (+) satisfactory poor very poor
1 3 4 2 1 0 1 1 0
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Applications & Installations
PV+Test results
Made in
Size (millimeters)
Weight
Cell type
Module type
Performance parameters
Specified power
IBC Solar
IBC Monosol 240 ET
Germany (OEM: Solarwatt)
1,680 mm x 990 mm x 50 mm
24.0 kg
monocrystalline 6’’ cells
Glass/EVA/cell/EVA/foil
240 watts
Output tolerance (negative / positive, in percent) 0/+2.1
Deviation of measured performance from specified performance +1.21
Measured performance within the specified performance tolerance
Efficiency under STC (1000 watts of solar radiation per m 2 , 25 °C, measured) 14.5
Efficiency reduction at low light levels (200 watts of solar radiation per m 2 ) -2.5
Temperature coefficient (percent) -0.465
Efficiency reduction at 50 degrees (temperature coefficient measured) -11.63
Fill factor 76.2
Evaluation of performance variance +++
Evaluation of low-light behavior +
Evaluation of temperature behavior -
Evaluation performance parameters (20%) ++
Aging behavior
Thermal cycling test (power degradation in percent) -0.38
Damp heat test, 1000 h (power degradation in percent) 1.3
Damp heat test, 1500 h (power degradation in percent) 0.0
Mechanical load test, 2400 Pascal (power degradation in percent) -0.8
Mechanical load test, 5400 Pascal (power degradation in percent) -0.5
Evaluation of the thermal cycling test ++
Evaluation of the damp heat test, 1000h +
Evaluation of the damp heat test, 1500h +++
Evaluation of the mechanical load test (2400 pascals) +++
Evaluation of the mechanical load test, very high load (5400 pascals) +++
Irregularities
Evaluation aging behavior (25%) ++
Documentation
IEC 61215/IEC 61730/CE label +/+/+
Irregularities
Evaluation documentation (15%) +++
Electrical safety
Results meet requirements of safety standard IEC 61730
Irregularities
Yes
Bubbles on the product label after the damp heat test
Information on materials, deviations P max , and protection
class were insufficient; instructions for grounding were
inadequate.
Yes
None
Evaluation electrical safety (25%) +++
Processing
Sharp edges (test according to UL)
Visible irregularities
None
Electroluminescence +++
Evaluation processing (10%) +++
Warranty and ease of installation
Product warranty
Performance guarantee 90% / 80%
Irregularities
Comments
Partly overlaying adhesive frame tapes, soldering was not
always perfect.
10 years
Evaluation warranty and ease of installation (5%) +++
Overall evaluation
Results within the requirements of IEC 61215 and IEC 61730
Overall evaluation (maximum 100 points) 89.8
12 years/25 years
Score good (+)
Installation, dismantling, and transport are not covered.
Relatively heavy (24 kg)
Yes
hours after the conclusion of the test because
moisture can diffuse back out of the
modules over time. That was also the case
with the IBC module. Subsequent measurements
showed that the insulation
value had returned to normal.
The precise point at which inverters
switch off varies from manufacturer to
manufacturer. Furthermore, the overall
concept of a photovoltaic system and the
size of the solar generator also determine
the resulting insulation resistance for the
system. Thus, the module is only one of a
number of possible factors.
“That is why PV+Test generally gives
higher evaluations to modules with
higher resistance,” says Cox. Nevertheless,
at no time during the testing procedure
did the IBC modules ever show
a worrying insulation value. If that were
the case, PV+Test would have drastically
lowered the overall score.
“The IBC modules merely showed
a strong relative decline which cost it
three points in the individual category,”
Cox said.
Documentation problem addressed
The module also lost points in a subevaluation
due to occasional imprecision
in the technical documentation. At
the time the tests were performed, some
data about the materials used in the modules,
potential deviations from the nominal
output, and information about the
protection class were missing. Furthermore,
as is the case with many other
manufacturers, instructions for grounding
the modules were inadequate. In the
interim, IBC Solar has responded and has
revised both the product specification
sheet and the installation instructions,
and now the documentation is comprehensive.
u
Mirco Sieg
Overview and contact
Every measurement is assigned a score
of between zero and ten points which
is weighted and incorporated into the
overall score. The table does not contain
all of the measurements underlying the
overall score. You’ll find a detailed description
and all of the PV+Test results at:
www.pv-magazine.com/pv-test
PV+Test is a registered trademark.
The table may only be reproduced or
distributed with the express consent of
Solarpraxis AG and TÜV Rheinland.
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04 / 2012 | www.pv-magazine.com