1. ESE 441: Solar Lantern
Christopher Howell, Salo Thiongane, & Danny Ventura
Prof. Eisaman
2. Goal
1. Goal to provide people in third world countries safer way to illuminate
their homes
1. Current option includes dangerous indoor kerosene lamps.
1. 1.6 billion people go into darkness when sun goes down since they are
without access to modern electricity.
1. Research concludes that kerosene is both inefficient and hazardous to
one’s health.
3. Project Objective:
Build a solar powered rechargeable LED lantern. Requirements:
1. Full battery charge provided by 10 hours of charging in sunlight.
2. Full battery charge yields 6 hours of LED light.
3. Illuminance of at least 100 lux at a distance of 2 feet from the lantern.
4. Battery lifetime of over 1000 charge-discharge cycles.
5. Ability to charge a cellphone.
6. Mechanical design to allow ease of use as a room light, table lamp, reading light, or flashlight.
7. Ability to withstand rain and humid environments.
8. Cost less than $100.
9. Modular: Can be shipped in pieces and assembled on site.
10. Can withstand being dropped from 10 ft.
11. Weighs less than 3 lbs.
12. Built in data logger for charge discharge cycles.
4. Design Approach:
● The first requirement to meet was the lux requirement,
the LEDs must be able to illuminate an area 2 feet away
with 100 lux.
● The battery was based off of how much current would be
needed to drive the LEDs at that illumination for six
hours.
● Then the solar panel could be chosen to fully charge that
battery with ten hours of sunlight.
5. High Power LED
● The forward voltage for this LEDs is rated at ~9V
● The LEDs generates a lot of heat
● A good heat sink is primordial in this case
● A heat sink is needed to make sure that the temperature
is being monitored.
6. High Power LED
● This LED contains multiple LEDs in itself
● These LEDs are used to build landing lights for aircraft
● It can output up to 500 lumens
● Illuminance of at least 100 lux at a distance of 2 feet from
the lantern.
7. Battery
Battery must be able to maintain the LEDs
for at least 6 hours. The battery chosen:
● Capacity of 5200 mAh.
● Discharge rate of 1C5A (discharge in 1 hour if 5A is being
drawn)
● Will allow for LEDs to be driven for 52 hours without
current being drawn anywhere else (with LEDs driven at
100mA)
● Voltage 3.7V
8. Final Battery
Final decision on battery was to connected three in series; this
will:
● Add the voltage to a total of 11.1V which will allow for a
simple voltage drop to drive the LEDs
● The current from the solar panel will flow thru each of
the batteries and will maintain 5200 mAh capacity
● A PCM which regulates the battery voltages between 2.4V
and 4.2V to protect from overcharging and over
discharging.
9. Solar Panel
Max Power Pmax 7.20W
Rated Voltage Vmax 15.0V
Rated Current Imax 0.48A
Open Circuit Voltage Voc 19.5V
Short Circuit Current Isc 0.52A
Dimensions (mm) 193 X 320 X 27.4
Weight lbs about 2.2 lbs
