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{{short description|Flashlights powered by solar energy}}
[[File:Solar radio 3.jpg|thumb|right|200px|A solar flashlight with built-in radio]]
[[File:Solar radio 3.jpg|thumb|right|200px|A solar flashlight with built-in radio]]
'''Solar powered flashlights''' are [[flashlight]]s that can be powered through [[solar energy]] using [[solar cell]]s as well as through [[Battery (electricity)|batteries]]. Most of these flashlights run on [[LED]] lights<ref>{{cite web|url=http://www.ledlights.org/LED-Flashlights/LED-Flashlight-Torch.html|title=LED Flashlight Torch|publisher=ledlights.org|accessdate=2011-07-08|work=}}</ref><ref>{{cite web|url=http://flashlightnews.org/story1204.shtml|title=Solar LED Flashlight with 20-Lumen Brightness|publisher=flashlightnews.org|accessdate=2011-07-08|work=}}</ref> due to the low energy consumption cost.<ref name=spf>{{cite web|url=http://www.solarpoweredflashlight.org/|title=Solar Powered Flashlight|publisher=solarpoweredflashlight.org|accessdate=2011-07-08|work=}}</ref>
'''Solar powered flashlights''' ([[American English]]) or '''solar powered torches''' ([[British English]]) are [[flashlight]]s powered by [[solar energy]] stored in rechargeable [[Battery (electricity)|batteries]]. Most of these flashlights use [[LED lighting|light-emitting diodes]] lamps<ref>{{cite web|url=http://www.ledlights.org/LED-Flashlights/LED-Flashlight-Torch.html|title=LED Flashlight Torch|publisher=ledlights.org|access-date=2011-07-08}}</ref><ref>{{cite web|url=http://flashlightnews.org/story1204.shtml|title=Solar LED Flashlight with 20-Lumen Brightness|publisher=flashlightnews.org|access-date=2011-07-08}}</ref> since they have lower energy consumption compared to [[incandescent light bulb]]s.<ref name=spf>{{cite web|url=http://www.solarpoweredflashlight.org/|title=Solar Powered Flashlight|publisher=solarpoweredflashlight.org|access-date=2011-07-08|url-status=dead|archive-url=https://web.archive.org/web/20120311221325/http://www.solarpoweredflashlight.org/|archive-date=2012-03-11}}</ref>


== Features ==
== Features ==
A typical flashlight can penetrate darkness to about 50 meters and the glow from the flashlight can be seen from upto 2 kilometers. The solar cells in the flashlight is capable of performing for 20 years. They can provide upto 6 hours of light when charged to about 6 hours.<ref name=spf/> Flashlights designed to be used in remote locations are shockproof and weatherproof<ref name=spf1/> in addition to being able to float.<ref>{{cite web|url=http://www.y2knorth.com/sunmate_flash.html|title=Solar-Powered Flashlight|publisher=y2knorth.com|accessdate=2011-07-08|work=}}</ref>
Solar powered flashlights vary in features and capabilities. A typical solar flashlight can give useful levels of illumination on objects up to 50 metres away, and beam may be visible for much longer distances. The solar cells used for battery charging have an indefinite life expectancy. A solar powered flashlight may give several hours of light after being charged during the day.<ref name=spf/> These flashlights may be designed to be impact resistant, weatherproof, and to float.<ref name=spf1/><ref>{{cite web|url=http://www.y2knorth.com/sunmate_flash.html|title=Solar-Powered Flashlight|publisher=y2knorth.com|access-date=2011-07-08}}</ref>


Other models include a wide variety of other features including a built in [[solar cell phone charger]]<ref>{{cite web|url=http://www.ecoseed.org/living-green/consumer-goods/article/48-consumer-goods/1743-solar-powered-torch-and-phone-charger-offered|title=Solar-powered torch and phone charger offered|publisher=ecoseed.org|accessdate=2011-07-08|work=}}</ref> AM/FM radio that has a high sensitivity the built-in FM antenna, a built in siren to call for help during an emergency, hand crank dynamo charging for use in night time etc., which can be used during outdoor activities and blackouts.<ref>{{cite web|url=http://flashlightnews.org/story862.shtml|title=Survival Center’s New Solar Powered Disaster Preparedness Flashlight/Radio|publisher=flashlightnews.org|accessdate=2011-07-08|work=}}</ref>
Other models include features such as a [[solar cell phone charger]],<ref>{{cite web|url=http://www.ecoseed.org/living-green/consumer-goods/article/48-consumer-goods/1743-solar-powered-torch-and-phone-charger-offered|title=Solar-powered torch and phone charger offered|publisher=ecoseed.org|access-date=2011-07-08|url-status=dead|archive-url=http://arquivo.pt/wayback/20160515215257/http://www.ecoseed.org/living-green/consumer-goods/article/48-consumer-goods/1743-solar-powered-torch-and-phone-charger-offered|archive-date=2016-05-15}}</ref> an AM/FM radio, or a siren to call for help in an emergency. Some models include a hand crank dynamo for charging at night.<ref>{{cite web|url=http://flashlightnews.org/story862.shtml|title=Survival Center's New Solar Powered Disaster Preparedness Flashlight/Radio|publisher=flashlightnews.org|access-date=2011-07-08}}</ref> An experimental solar flashlight the size of a credit card features a white LED powered by 16 solar cells.<ref>{{cite web|url=http://www.rsc.org/chemistryworld/News/2011/August/08081101.asp|title=A torch to fit in your back pocket|publisher=rsc.org|access-date=2011-08-08}}</ref>


== Comparison with primary battery flashlights ==
== Battery life ==
⚫
Solar powered lights need not be manually recharged as in the case of conventional battery operated flashlights.<ref name=spf/> Pollution from discarded batteries used in normal flashlights is eliminated.<ref name=spf1>{{cite web|url=http://www.solarpoweredflashlight.org/how-to-pick-the-best-solar-powered-flashlight/|title=How to Pick the Best Solar Powered Flashlight|publisher=solarpoweredflashlight.org|access-date=2011-07-08}}</ref> Solar powered flashlights can be used in remote locations where it is impossible to find any source of electricity except for solar power.<ref name=spf1/>
To maximize your battery life on the solar flashlight, it is recommended that the battery be fully drained at least once a month. Doing so would erase any [[battery memory]] that is created from half-charges.<ref name=spf/>


A built-in solar cell array in a hand-held product has a very small capacity. The light output and run time of the solar flashlight are limited by the amount of energy that can be absorbed in a day. Flashlights are usually stored indoors or otherwise out of direct sunlight; consumers may find it inconvenient to remember to place the flashlight in full sunlight for several hours before use. Rechargeable cells self-discharge, so unless the flashlight is stored in a sunny location, the light may not function in an emergency. Rechargeable cells have a finite charge/discharge cycle life, and when the cells wear out it may be difficult for the consumer to replace them. Some of these disadvantages can be mitigated by separating the solar cell array from the flashlight, but then the simplicity of automatic charging is lost.<ref>http://escholarship.org/uc/item/2714q6kz#page-10 Kristen Radecsky, ''Solid-State Lighting on a Shoestring Budget: The Economics of Off-Grid Lightign for Small Businesses in Kenya'', Lawerence Berkeley National Laboratory, 2009</ref>{{citation needed|date=January 2012}}
== Innovations ==
A group of scientists from [[Denmark]] and the [[US]] have developed a solar flashlight no larger than a credit card. It features a white LED powered by 16 solar cells. When tests were conducted on the flashlight to determine its efficiency and study the effects of humidity on its performance, it was concluded that the general efficiency of the flashlight is at 89%.<ref>{{cite web|url=http://www.rsc.org/chemistryworld/News/2011/August/08081101.asp|title=A torch to fit in your back pocket|publisher=rsc.org|accessdate=2011-08-08|work=}}</ref> However, manufacturing the flashlight is a complicated procedure that involves up to 35 steps, and the flashlight is not ready for consumer manufacturing.

== Advantages ==
* Solar powered lights need not be manually recharged as in the case of conventional battery operated flashlights.<ref name=spf/>

⚫
* Pollution from discarded batteries used in normal flashlights is eliminated.<ref name=spf1>{{cite web|url=http://www.solarpoweredflashlight.org/how-to-pick-the-best-solar-powered-flashlight/|title=How to Pick the Best Solar Powered Flashlight|publisher=solarpoweredflashlight.org|accessdate=2011-07-08|work=}}</ref>

* Solar powered flashlights can be used in remote locations where it is impossible to find any source of electricity except for solar power.<ref name=spf1/>


== Significance ==
== Significance ==
Solar powered flashlights have been distributed to countries where there is either none or erratic power supply, helping people feel safer leaving their homes at night, and giving children the opportunity to study after sunset.<ref>{{cite web|url=http://lighthaiti.org/press/USAA_Mag_SunNight.pdf|title=Lighting the world|publisher=lighthaiti.org|accessdate=2011-07-08|work=}}</ref><ref>{{cite web|url=http://www.tanzanianchildrensfund.org/wish_list.htm|title=Wish List for the Rift Valley Children’s Village|publisher=tanzanianchildrensfund.org|accessdate=2011-07-08|work=}}</ref> A dual purpose solar flashlight, which also functions as a lamp has helped families in such countries spend more time together, surgeries to be performed during power outages and people to travel in the dark under a halo of light.<ref>{{cite web|url=http://m.rockfound.org/uploads/files/b016baf0-79ab-41b1-94c3-15088e6d5771-sunnight.pdf|title=Case study: SunNight solar|publisher=m.rockfound.org|accessdate=2011-07-08|work=}}</ref><ref>{{cite web|url=http://edge.rit.edu/content/P08427/public/Business%20Plan.pdf|title=Green Power - Business Plan|publisher=edge.rit.edu|accessdate=2011-07-08|work=}}</ref><ref>{{cite web|url=http://edweb.sdsu.edu/sdpca/back_issues/v21n1.html|title=Scaling for the Poor - The task of turning good ideas into greater good|publisher=edweb.sdsu.edu|accessdate=2011-07-08|work=}}</ref>
Solar powered flashlights have been distributed to countries where there is either no or erratic power supply, helping people feel safer leaving their homes at night, and giving children the opportunity to study after sunset.<ref>{{cite web|url=http://lighthaiti.org/press/USAA_Mag_SunNight.pdf|title=Lighting the world|publisher=lighthaiti.org|access-date=2011-07-08}}</ref><ref>{{cite web|url=http://www.tanzanianchildrensfund.org/wish_list.htm|title=Wish List for the Rift Valley Children's Village|publisher=tanzanianchildrensfund.org|access-date=2011-07-08}}</ref> A dual purpose solar flashlight, which also functions as a lamp has helped families in such countries spend more time together, surgeries to be performed during power outages and people to travel in the dark under a halo of light.<ref>{{cite web|url=http://m.rockfound.org/uploads/files/b016baf0-79ab-41b1-94c3-15088e6d5771-sunnight.pdf|title=Case study: SunNight solar|publisher=m.rockfound.org|access-date=2011-07-08}}</ref><ref>{{cite web|url=http://edge.rit.edu/content/P08427/public/Business%20Plan.pdf|title=Green Power - Business Plan|publisher=edge.rit.edu|access-date=2011-07-08}}</ref><ref>{{cite web|url=http://edweb.sdsu.edu/sdpca/back_issues/v21n1.html|title=Scaling for the Poor - The task of turning good ideas into greater good|publisher=edweb.sdsu.edu|access-date=2011-07-08}}</ref>


== See also ==
== See also ==
⚫
{{Portal|Renewable energy|Energy}}
* [[Flashlight]]
* [[Self-powered equipment]]
* [[Self powered equipment]]
* [[List of solar powered products]]
* [[Solar cell phone charger]]


== References ==
== References ==
{{Reflist}}
{{Reflist|2}}

== See also ==
⚫
{{Portal box|Renewable energy|Energy}}
* [[Solar cell phone charger]]
* [[Solar notebook]]
* [[Solar powered calculator]]
* [[Solar powered fountain]]
* [[Solar powered radio]]
* [[Solar fan]]
* [[Solar street light]]
* [[Solargoose]]



{{Photovoltaics}}
{{Photovoltaics}}


{{DEFAULTSORT:Solar Powered Flashlight}}
{{DEFAULTSORT:Solar Powered Flashlight}}
[[Category:Photovoltaics]]
[[Category:Applications of photovoltaics]]
[[Category:Flashlights]]

Latest revision as of 14:30, 24 October 2023

A solar flashlight with built-in radio

Solar powered flashlights (American English) or solar powered torches (British English) are flashlights powered by solar energy stored in rechargeable batteries. Most of these flashlights use light-emitting diodes lamps[1][2] since they have lower energy consumption compared to incandescent light bulbs.[3]

Eigenschaften

[edit]

Solar powered flashlights vary in features and capabilities. A typical solar flashlight can give useful levels of illumination on objects up to 50 metres away, and beam may be visible for much longer distances. The solar cells used for battery charging have an indefinite life expectancy. A solar powered flashlight may give several hours of light after being charged during the day.[3] These flashlights may be designed to be impact resistant, weatherproof, and to float.[4][5]

Other models include features such as a solar cell phone charger,[6] an AM/FM radio, or a siren to call for help in an emergency. Some models include a hand crank dynamo for charging at night.[7] An experimental solar flashlight the size of a credit card features a white LED powered by 16 solar cells.[8]

Comparison with primary battery flashlights

[edit]

Solar powered lights need not be manually recharged as in the case of conventional battery operated flashlights.[3] Pollution from discarded batteries used in normal flashlights is eliminated.[4] Solar powered flashlights can be used in remote locations where it is impossible to find any source of electricity except for solar power.[4]

A built-in solar cell array in a hand-held product has a very small capacity. The light output and run time of the solar flashlight are limited by the amount of energy that can be absorbed in a day. Flashlights are usually stored indoors or otherwise out of direct sunlight; consumers may find it inconvenient to remember to place the flashlight in full sunlight for several hours before use. Rechargeable cells self-discharge, so unless the flashlight is stored in a sunny location, the light may not function in an emergency. Rechargeable cells have a finite charge/discharge cycle life, and when the cells wear out it may be difficult for the consumer to replace them. Some of these disadvantages can be mitigated by separating the solar cell array from the flashlight, but then the simplicity of automatic charging is lost.[9][citation needed]

Significance

[edit]

Solar powered flashlights have been distributed to countries where there is either no or erratic power supply, helping people feel safer leaving their homes at night, and giving children the opportunity to study after sunset.[10][11] A dual purpose solar flashlight, which also functions as a lamp has helped families in such countries spend more time together, surgeries to be performed during power outages and people to travel in the dark under a halo of light.[12][13][14]

See also

[edit]

References

[edit]
  1. ^ "LED Flashlight Torch". ledlights.org. Retrieved 2011-07-08.
  2. ^ "Solar LED Flashlight with 20-Lumen Brightness". flashlightnews.org. Retrieved 2011-07-08.
  3. ^ a b c "Solar Powered Flashlight". solarpoweredflashlight.org. Archived from the original on 2012-03-11. Retrieved 2011-07-08.
  4. ^ a b c "How to Pick the Best Solar Powered Flashlight". solarpoweredflashlight.org. Retrieved 2011-07-08.
  5. ^ "Solar-Powered Flashlight". y2knorth.com. Retrieved 2011-07-08.
  6. ^ "Solar-powered torch and phone charger offered". ecoseed.org. Archived from the original on 2016-05-15. Retrieved 2011-07-08.
  7. ^ "Survival Center's New Solar Powered Disaster Preparedness Flashlight/Radio". flashlightnews.org. Retrieved 2011-07-08.
  8. ^ "A torch to fit in your back pocket". rsc.org. Retrieved 2011-08-08.
  9. ^ http://escholarship.org/uc/item/2714q6kz#page-10 Kristen Radecsky, Solid-State Lighting on a Shoestring Budget: The Economics of Off-Grid Lightign for Small Businesses in Kenya, Lawerence Berkeley National Laboratory, 2009
  10. ^ "Lighting the world" (PDF). lighthaiti.org. Retrieved 2011-07-08.
  11. ^ "Wish List for the Rift Valley Children's Village". tanzanianchildrensfund.org. Retrieved 2011-07-08.
  12. ^ "Case study: SunNight solar" (PDF). m.rockfound.org. Retrieved 2011-07-08.
  13. ^ "Green Power - Business Plan" (PDF). edge.rit.edu. Retrieved 2011-07-08.
  14. ^ "Scaling for the Poor - The task of turning good ideas into greater good". edweb.sdsu.edu. Retrieved 2011-07-08.
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