|geoffrey ||8th December 2007 16:06 |
Rechargeable 'Shake' Led Lamp
Some of you might know the following type of lamp:
The Forever Flashlight uses no batteries or bulbs. Instead it uses Faraday's Principle of Magnetic Induction and a bright LED to produce light without batteries. The flashlight is shaken for about 30 seconds to recharge a capacitor and it will then provide about 5-7 minutes of light. How does this happen? As the flashlight is shaken, a magnet passes through a metal coil which, when you shake, "induces" voltage in the coil generating electricity. During prolonged use it can be shaken for 10-15 seconds every 2 or 3 minutes for bright light. The light requires no maintenance so it can be left in your home or car for years, but will still be ready to produce light. The bright LED will last for thousands of hours and does not burn-out like a typical lightbulb- it should never need replacement. Great for home, car, camper, boat, or emergencies. Imagine exploring without of fear of ever running out of light. No need to worry about light if your car dies during a dark and stormy night. You'll be in great shape even if you have to signal for help in the pouring rain because it's 100% waterproof and it even floats! It gives you a powerful beam of light visible for up to a mile. This is a flashlight that never needs batteries, replacement parts or even bulbs for that matter. Now that's peace of mind. Features: Super bright blue/white LED bulb. Powered by principles of Faraday's Principle of Induction. Never needs batteries, vever needs bulbs, maintenance free. Save money- never have to buy batteries. 100% Waterproof case & even floats in water. Light visible for up to one mile. Great for cars, boats, campers, homes, cottages and all emergency kits. 30 seconds of shaking powers LED for 5-7 minutes.
Inside you'll find a single bright white LED which is being feed via a handy rechargeable 'coil-magnetic core' device. In order to be able to switch on the lamp, just shake with it, the magnetic core will then travel through the inside of the coil which will produce electricity. At least, that's the theory behind it.
Our sample functioned great over longer periods of time, even after 1h the power circuit remained its charge. This got me thinking, can I upgrade my lamp with more LED's so that it will produce more light? So, I opened up the lamp, which is transparent, and inside I found a black 'thing' which was what I thought a capacitor which stores the produced energy. I removed the black cover, hoping to get a view on what kind of capacitor was being used, but inside I found nothing more then two small batteries.
We've been fooled! We measured the shaking device, in slow movements we got around 0,02mV out of it which is far from very usable to charge a capacitor. Besides that we found no tool which switches polarity in order to get direct current, this thing was never made to work, at least not without the batteries :)
Our tool was very cheap and seemed to be an excellent bargain, but in real life it did not offer enough light to be of good use and it's 'no-battery' label is just a simple lie. Another "beware with what you buy", just wanted to share though, hope you got not fooled like us.
PS: Regarding shake lights, it seems like those things really exist, but their use is still questionable over normal rechargeable lights, if you got some input I'd be glad to listen to your story.