India has a young population that will continue growing, with over 29% under 14 years old in 2011. For India to grow fast, its young people need good education. The document proposes a solution called SOUL, a solar-powered LED lamp, to provide lighting for studying. It details the design of the lamp's LED, housing, battery, solar panel, and electronics to efficiently provide 6-7 hours of 280-lux light daily from a small, inexpensive system. The proposed design aims to empower children through access to light for studying.

3. Introduction
India is a Young country
• July 2011-Population = 1189 million of which
– 0-14 years: 29.7%
– 15-64 years: 64.9%
– 65 years and over: 5.5%
• Dependency ratio of 0.6; 2030-0.4
• 2020 Average Age: India-29; China-37; Japan-48:
 India will have youngest working age population in world
 With this young population India ‘can’ grow fast, provided
the young population is well-educated and well-trained

4. Continued…..
“Right to Education” successfully implemented by
Government of India through “Sarva Sikhsha Abhiyan”
Need to implement “Right to Clean Light”
LED based Solar Urja Lamp (SOUL) is a Solution to “Right
to Clean Light”
The power consumption for SOUL whole year is even less
than a 1 unit

5. DPerodsuicgt Dnes igPn rospective:
Light Right Design
Electrical Design
Solar Panel Design

6. Product Design
LED
Housing
LED
Gooseneck
Base of Lamp
1 feet
height
SOUL product model

7. Light Design
The standard lux level for general purpose lighting is 150 lux and that for
studying is 250 lux according to the international standards for lighting.
The LED is a 150 lumen per watt
Mode Powe
r
(W)
Table for Lux level calculations:
Lumen Exposed
Area under
lamp
(m2)
Lux
(Lumen/
m2)
Standard Light
level
(Lux)
1 0.192 28.8 0.185 155 150 (general)
2 0.352 52.8 0.185 285 250 (study)
Mode 1: low intensity
Mode 2 : high intensity

8. Battery Electronics
Controller
Electrical Design
Solar Panel
LED
Sun
SOUL basic electrical model

9. 1. LED Technical Specifications:
Operating Voltage Power Consumption (Pmax) Luminance
3.2 V 0.5 Watts 75 lumen
2. Design Table for calculation of battery capacity
Mode Volt
(V)
Current
(A)
Power
(W)
Energy
(Whr)
Efficiency
(%)
Energy
(Whr)
Battery
voltage
(V)
Charge
(mAh)
Electrical Design (Cont..)
DoD
(%)
Capacity
(mAh)
1 3.2 0.06 0.192 1.54 85 1.81 2.4
(NiMH)
753 80 941
2 3.2 0.11 0.352 1.76 85 2.07 2.4
(NiMH)
863 80 1078
1 3.2 0.06 0.192 1.54 85 1.81 3.7
(Li Ion)
490 80 611
2 3.2 0.11 0.352 1.76 85 2.07 3.7
(Li Ion)
560 80 700

10. Design Table for calculation of Solar Panel capacity
3. Design Table for calculation of Solar Panel capacity
Mode Energy
(Wh)
Battery
Efficiency
(%)
Energy
(Wh)
Sunshine
Hours
(H)
Power
(W)
Fill
Factor
(%)
• Nearest available capacity of battery is 1200 mAh NiMH
• Peak Power rating of solar module can be 1 approximated to
1 Wp
Electrical Design (Cont..)
Peak
Power
(Wp)
1 1.81 90 2.01 4.5 0.447 70 0.64
2 2.07 90 2.30 4.5 0.511 70 0.73

11. Solar cell parameters:
Power O/P of Solar Panel : 1 W
Voltage : 0.47 V
Current density : 30 mA/m2
Temp : 25 C.
Voltage Coefficient : 2.3 mV/ C
Vmp (STC)
V
Temp coefficient
mV/ C
Temp difference
C
Voltage drop per cell
Solar Panel Design
V
Net Voltage
per cell
V
0.47 2.3 40 0.092 0.378
• Battery voltage : 2.4 V
• Charging voltage : 2.4 + 1.4 = 3.8 V
• No. of Cells = 3.8 V ÷ 0.378 V = 10 numbers
(approx.).

12. No. of Cells = 3.8 V ÷ 0.378 V = 10 numbers (approx).
Power Rating /Cell = 1 W ÷ 10 = 0.1 W.
Current Rating /Cell = 0.1 W ÷ 0.47 V = 0.212 A = 212
mA.
Area of each Cell = 212 mA ÷ 30 mA/sq. cm. = 7 sq. cm.
Total area of 10 Cells = 10 x 7 sq. cm. = 70 sq. cm.
Packaging density = 50 %
Area of panel Panel = 70 sq. cm. ÷ 0.5 = 140 sq. cm
Solar Panel Design (cont…)

13. A powerful component of design for need which looks at the
user needs, service needs , distribution issues and most
important the empowerment of children .
The design using the best technology for various components
and deploying it in system
The proposed solar study lamps will have
◦ 0.5 Wp solar panel
◦ 0.5 Watt LED
◦ 1200 mAH of battery storage
◦ Provides light intensity of about 280 Lux (good enough for
Conclusion:
study)
◦ 6 to 7 hours of daily service.

14. Thanks For your attention ! 