Download Solar Lamps Evaluation

Evaluation Objective:
The objective of this report is to evaluate the D1 Solar Lamp Light and measure the light output in
lumens.
This evaluation report is an independent review of light output of Dlight solar lights. It is suggested to
refer to the manufacturer’s product specification for specific product data.
Author: Cheryl Champagne
Date: 07/02/2012
Revised 10/03/2012
1. Scope: To measure the light output in lumens of two solar lamps, the D1 small and D1 tall.
2. Definition:
Brightness is a description of light output, which is measured in lumens (not watts).
Two important measurements of white light (sunlight) quality are correlated color temperature (CCT) and color rendering
index (CRI).
CCT describes whether white light appears warm (reddish), neutral, or cool (bluish). The standard definitions of CCT
allow a range of variation in color that can be readily discerned by viewers even when the CCT value is the same.
On a scale of 0 (worst) to 100 (best), CRI measures the ability of a light source to reproduce the colors of objects faithfully
in reference to an ideal light source — the sun. Most office, retail, educational, medical, and residential spaces require a
minimum CRI of 70 – 90. Many white-light LED lighting fixtures available today achieve CRIs of 80 or better.
The color of light (hue) may also affect how bright a light appears, even if the lumens are the same. Light closer to the
color of daylight ( the Sun,color temperatures above 3000K) may appear brighter because the color of the light is pure
white. Where a light falls on the Chromacity chart will show how close to natural sun light the measured light is at. It is a
subjective view, some folks prefer a more yellow light (incandecent) some more of a blue. The attempt here is to show
how close to natural daylight the solar lamps are.
Wave length of UV light falls under 360 nm as IR wavelengths are above 750 nm on the light spectrum.
3. Material/Equipment:
3.1 D Tall solar Lamp
3.2 DSmall solar lamp
3.4 GigahertzOptik Model BTS256-LED measuring instrument and software
3.5 Dell Laptop
4. Purpose
1.1 The purpose of this evaluation is to verify the Solar Lamp Light Output in lumens of two models of the
D1 solar lamps.
5. Analysis
Measure the Light Output via integrating sphere and record data in numeric and graphical form for
evaluation report.
Small:
Ra is the average CRI = 87.3
Light Output = 36 Lumens
wavelength of LED light
Chromacity
Large:
Ra is the average CRI =86.5
Lumens = 36
wavelength of LED light
Chromacity
5. Results:
The light output of both lamps equal 36.9 Lumens which is equivalent to approximately a 3.9 watt incandescent bulb.
INCANDESCENT
BULBS
(WATTS)
25
40
60
75
100
125
150
MINIMUM LIGHT
OUTPUT
(LUMENS)
250
450
800
1,110
1,600
2,000
2,600
The CRI level are within .5 at 86.5 and 87.2 between the two lamps. A CRI above 70 is considered acceptable white light.
On the small lamp, the wavelengths did not drop off (below zero) at 720-750 nm range as they did on the larger lamp. It
would not be recommended to look directly into the light of the small lamp. The wavelength for IR on the larger lamp
drops off at 650 nm. The UV wavelength for both lamps is at or near zero.
The Chromacity level of the small lamp is closer to natural white light (sunlight) than the larger one. The larger one has a
bit of yellow hue.
6.
Conclusion:
Either lamp will light a small area such a an entry way or very small room for a few hours.