Greentubes SL12/6500.

Posted by Marcel van der Steen in Lamps, Light measurements No Comments»

greentubes_silverline Greentubes BV presents a 120 cm long tube light. It is a small fluorescent tube in a transparent plastic outer tube which serves as the housing. At the back side of the inner fluorescent tube a reflector is seated with a white color. At the back side (against the inner back side of the outer tube) a heat sink is positioned. The heat sink is seated inside the transparent plastic outer tube.

This article shows the measurement results. Many parameters are also found in the Eulumdat file.

See this overview for a comparison with other light bulbs.

Summary measurement data

parameter meas. result remark
Color temperature 6629 K Cold white
Luminous intensity Iv 473 Cd Measured straight underneath the lamp
Beam angle 181 deg 181º for the C0-C180 plane (crosses the length direction of the tube), and 107º for C90-C270 plane (along the length direction of tube).
Power P 25.2 W Follow the link for more electrical and temperature properties.
Power Factor 0.93 For every 1 kWh net power consumed, there has been 0.4 kVAhr for reactive power.
Luminous flux 2036 Lm
Luminous efficacy 81 Lm/W
EU-label classification A The energy class, from A (more efficient) to G (least efficient).
CRI_Ra 84 Color Rendering Index.
Coordinates chromaticity diagram x=0.3080 and y=0.3436
Fitting FL-tube This energy saving retrofit T5 tube is connected directly to the 230 V grid.
PAR-value 4.3 μMol/s/m2 The number of photons seen by an average plant when it is lit by the light of this light bulb. Value valid at 1 m distance from light bulb.
PAR-photon efficacy 0.7 μMol/s/We The toal emitted number of photons by this light, divided by its consumption in W. It indicates a kind of efficacy in generating photons.
S/P ratio 2.3 This factor indicates the amount of times more efficient the light of this light bulb is perceived under scotopic circumstances (ow environmental light level).
D x L external dimensions 32 x 1196 mm External dimensions of the lamp (D = diameter, L = Length without pins).
L x W x H luminous area 1107 x 30 x 7 mm Dimensions of the luminous area (used in Eulumdat file). This is equal to the surface of area of the reflector and the height is the top hald of the fluorescent tube.
General remarks The ambient temperature during the whole set of measurements was 23.5-25 deg C. The average temperature of the tube light gets about 16 degrees hotter than ambient. The maximum temperature point was 25 degrees warmer.
Warm up effect: during the warm up time the illuminance increases to more than 200 % of the initial value.

Voltage dependency: the power consumption and illuminance do linearly depend on the voltage when it is varied from 200 – 250 V.

Measurement report (PDF) olino-pdf
Eulumdat file olino_eulumdat Right click on icon and save the file.

Overview table


The overview table is explained on the OliNo website. Please note that this overview table makes use of calculations, use this data with care as explained on the OliNo site. E (lux) values are not accurate, when within 5 x 1107 mm ≈ 5500 mm. Within this distance from the lamp, the measured lux values willl be less than the computed values in this overview as the measurements are then within the near field of the lamp.

Note II: the illuminated area (ø 50%) in the C0-C180 plane is not relevant as the beam angle there is >= 180º.

EU Energy label classfication

With the measurement results of the luminous flux and the consumed power the classification on energy of this lamp is calculated. This information is requested in the EU for certain household lamps, see also the OliNo site that explains for which lamps it is requested, how the label looks like and what information it needs to contain.

Herewith the labels for this lamp in color and black and white.

EU energy label of this lamp

Label in black and white.

Eulumdat light diagram

This light diagram below comes from the program Qlumedit, that extracts these diagrams from an Eulumdat file. It is explained on the OliNo site.


The light diagram giving the radiation pattern.

It indicates the luminous intensity around the light bulb. The direction C90-C270 has a smaller beam than the C0-C180. This latter emits in a wide angle.

Illuminance Ev at 1 m distance, or luminous intensity Iv

Herewith the plot of the averaged luminous intensity Iv as a function of the inclination angle with the light bulb.


The radiation pattern of the light bulb.

This radiation pattern is the average of the light output of the light diagram given earlier. Also, in this graph the luminous intensity is given in Cd.

These averaged values are used (later) to compute the lumen output.


Intensity data of every measured turn angle at each inclination angle.

This plot shows per inclination angle the intensity measurement results for each turn angle at that inclination angle. There normally are differences in illuminance values for different turn angles. However for further calculations the averaged values will be used.

When using the average values per inclination angle, the beam angle can be computed, being 181º for the C0-C180 plane (crossing the length direction) and 107º in the C90-C270 plane (along the length direction).

Luminous flux

With the averaged illuminance data at 1 m distance, taken from the graph showing the averaged radiation pattern, it is possible to compute the luminous flux.

The result of this computation for this light spot is a luminous flux of 2036 Lm.

Luminous efficacy

The luminous flux being 2036 Lm, and the power of the light bulb being 25.2 W, yields a luminous efficacy of 81 Lm/W.

Electrical properties

A power factor of 0.93 means that for every 1 kWh net power consumed, a reactive component of 0.4 kVAr was needed.

Lamp voltage 230 VAC
Lamp current 118 mA
Power P 25.2 W
Apparent power S 27.1 VA
Power factor 0.93

Of this light bulb the voltage across ad the resulting current through it are measured and graphed. See the OliNo site how this is obtained.


Voltage across and current through the lightbulb

This waveforms have been checked on requirements posed by the norm IEC 61000-3-2:2006 (including up to A2:2009). See also the explanation on the OliNo website.


Harmonics in in the current waveform and checked against IEC61000-3-2:2006

There are limits for the harmonics for led lighting equipment > 25 W. Some of these limits are not met, see the image for the indication of the frequencies. Further it will be shown that the 230 V grid voltage used is slightly out of required norm specification, which will have a deteriorating effect on the resulting current harmonics. Therefore this result of the harmonics in the current must not be interpreted as definite, but as a serious indication.

The used grid voltage is also checked against the requirements in the norm.


The norm harmonic limits and the check of the voltage used

The used grid voltage has slightly more harmonic content than the current prescribes. As the voltage ha smore harmonic content, then it will negatively affect the harmonics in the resulting current. The harmonic content in the current must therefore be seen as a serious indication.

The Total Harmonic Distortion of the current is computed as 33 %.

Temperature measurements lamp


Temperature image  (warmest side) of the light bulb

Tape is put on the hottest side. The square in the image shows the temperature area on this tape. Also a measurement point is given of the hotspot near the tube end.

status lamp > 2 hours on
ambient temperature 24 deg C
reflected background temperature 24 deg C
camera Flir B-CAM Western S
emissivity 0.95(1)
measurement distance 0.20 m
IFOVgeometric 0.7 mm
NETD (thermal sensitivity) 100 mK

(1) The emissivity of the masking tape is used which is about 0.95. The masking tape is so thin that it quickly takes the same temperature as the light bulb’s heat sink.

The tube on its hotttest side (approximately 40 degrees) gets no warmer than warm-to-the-touch. The hotspot seen gets to 49 deg C.

Color temperature and Spectral power distribution


The spectral power distribution of this light bulb, energies on y-axis valid at 1 m distance.

The measured color temperature is about 6625 K which is cold white.

This color temperature is measured straight underneath the light bulb. Below a graph showing the color temperature for different inclination angles.


Color temperature as a function of inclination angle.

The measurement of CCT is measured for inclination angles up to 70º since then the illuminance value was decreased to very low values (< 5 lux).

The beam angle for the C0-C180 is 181º, meaning a 90.5º inclination angle. In this area the majority of the light is present. The variation in correlated color temperature in this area is < 1 %.

The beam angle for the C90-C270 is 107º, meaning a 53.5º inclination angle. In this area the majority of the light is present. The variation in correlated color temperature in this area is ≈ 1 %.

PAR value and PAR spectrum

To make a statement how well the light of this light bulb is for growing plants, the PAR-area needs to be determined. See the OliNo website how this all is determined and the explanation of the graph.


The photon spectrum, then the sensitivity curve and as result the final PAR spectrum of the light of this light bulb

parameter value unit
PAR-number 4.3 μMol/s/m²
PAR-photon current 18.6 μMol/s
PAR-photon efficacy 0.7 μMol/s/W

The PAR efficiency is 65 % (valid for the PAR wave length range of 400 – 700 nm). So maximally 65 % of the total of photons in the light is effectively used by the average plant (since the plant might not take 100 % of the photons at the frequency where its relative sensitivity is 100 %).

S/P ratio

The S/P ratio and measurement is explained on the OliNo website. Here the results are given.

The power spectrum, sensitivity curves and resulting scotopic and photopic spectra (spectra energy content defined at 1 m distance).

The S/P ratio is 2.3

More info on S/P ratio can be found on the OliNo website.

Chromaticity diagram


The chromaticity space and the position of the lamp’s color coordinates in it.

The light coming from this lamp is at a distance from the Planckian Locus (the black path in the graph).

Its coordinates are x=0.3080 and y=0.3436.

Color Rendering Index (CRI) or also Ra

Herewith the image showing the CRI as well as how well different colors are represented (rendered). The higher the number, the better the resemblance with the color when a black body radiator would have been used (the sun, or an incandescent lamp). Practical information and also some critics about the CRI can be found on the OliNo website.

Each color has an index Rx, and the first 8 indexes (R1 .. R8) are averaged to compute the Ra which is equivalent to the CRI.


CRI of the light of this lightbulb.

The value of 84 is higher than 80 which is considered a minimum value for indoor usage.

Note: the chromaticity difference is 0.0074 indicates the distance to the Planckian Locus. There is no norm yet that states what the max deviation from white light is allowed to be.

Voltage dependency

The dependency of a number of lamp parameters on the lamp voltage is determined. For this, the lamp voltage has been varied and its effect on the following light bulb parameters measured: illuminance E_v [lx], the lamppower P [W], the (Correlated) Color Temperature [K] and the luminous efficacy [Lm/W].


Lamp voltage dependencies of certain light bulb parameters, where the value at 230 V is taken as 100 %.

The illuminance and consumed power do vary when the voltage is varied, in a linear matter.

When the voltage at 230 V varies with + and – 5 V, then the illuminance varies 2 %, so when abrupt voltage changes occur this effect is not visible in the illuminance output.

Warm up effects

After switch on of a cold lamp, the effect of heating up of the lamp is measured on illuminance E_v [lx], color temperature CT or correlated color temperature CCT [K], the lamppower P [W] and the luminous efficacy [lm/W].



Effect of warming up on different light bulb parameters. At top the 100 % level is put at begin, and at bottom at the end.

The warm up time is about 5 minutes. During that time the illuminance increases to about 2.3 x the initial value.

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