This looks like an interesting solar camping light project.
“The unit contains a solar controller board from the Electronics Goldmine that turns the light on at dusk and off at dawn. The batteries are two lithium 3.6 v cells in series, providing 7.2 v @ 1.1 amp hours. The two white LEDs are in series and draw 20ma. The only other parts used are a switch and power connector for the solar panel connection. I would have preferred a white box for the project since it is in the sun for charging.
The board contains a 358 dual op amp. One op amp is used to turn the light on at dusk and off at dawn and the second is used to turn off the light when the battery drops to about 5.5 volts. The CDS cell pokes through a hole drilled in the box. There are various ways to mount the LEDs. Not having any mounting hardware at the time, I mounted them to a circuit board which I bolted to the box.”
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I Would like to warn about the way he’s charging the Litium-Ion Cells. He has taken a mobile phone battery apart, removing what he “thinks” is charging circuitry, but actually safety-electronics, and VERY vital for the batteries. Lithium-Ion batteries is like explosives, if handled wrong. If you charge OR discharge it too much the internal chemistry can become unstable and a thermal meltdown is possible. making this construction with the safety electronics in place is more safe. for say two nokia 3310 or equal cells in their housing is safe. if you do something the battery doesn’t like, it’s just disconnected from the terminals by the safety electronics. say you short circuit it, nothing happens. as soon as a valid charging voltage appears on the terminals, the electronics open up again.
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Litium-Ion cells are very dangerous without special charge protection circuits. I don’t see any protection in this project. The author mentions discharge protection but the major danger is with overcharging.
Maybe this works OK becasue the solar panel does not provide any current at the charged voltage of the batteries. Readers that may want to create their own version need to be extreamly carful with battery and solar cell selection.
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The G4601 controller is sold out.
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but why do you need a light if there is sunlight? 😛
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I’ve been working on something similar for my backpack, charges my cellphone, mp3 player, and laptop, when one gets fully charged it cuts off, leds in the strap of the bag, along with a wifi sniffer’s leds.
Always great so see another solar project 🙂
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It is brilient project. solar powered camping lights in your outdoor activities is one way you can make a difference in the future of the planet. This solar powered campinf light is save the electricity.
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John Smith
http://www.goinggreenbuzz.com