Sukhbinder Posted December 7, 2005 Report Share Posted December 7, 2005 Hi guys, i just saw on the net at http://cgi.ebay.co.uk/Induction-Charged-LED-Torch-No-Batteries-Ever-NEW_W0QQitemZ8730468431QQcategoryZ117110QQcmdZViewItema LED torch which used no batteries. I've seen such devices earlier also , they shake the torch to charge it up and it work for 15-20mins. Using a LED reduces the current drain. I got one like it at fair but it was a duplicate one with 2 3V lithium batteries powering it. There is a coil in it but not conected. I need to add a magnet but i need some one to suggest a way to store the charge. if i connect a capacitor to the coil, the cap will be charged a bit by the coil when i shake it but will it not also discharge through the coil when the torch is stationary. Also when the magnet moves in one direction and then in the other direction won't the direction of voltages generated be opposite (more like AC and don't Capacitors act as short circuit to AC voltages) I f one needs DC we need to rectify it but how to rectify small voltages with common diodes. How to store the charge and let the discharge be gradual as from my previous experieces if u connect an LED to a charged cap, the led gives a flash of light and then glows dimly until the cap is completly discharged. Any ideas for this? since i have the enclosure fitted with a single white LED, a reflector and a convex lens glass in the front, i may be able to make a working prototype with help from u guys. :D Quote Link to comment Share on other sites More sharing options...
Sukhbinder Posted December 7, 2005 Author Report Share Posted December 7, 2005 sorry guys the working time is 5 mins as per this site but i remember seeing 15 min at some other site. u need to shake it for 15-30 sec and u get a working time of 5 mins.:D Quote Link to comment Share on other sites More sharing options...
Ldanielrosa Posted December 7, 2005 Report Share Posted December 7, 2005 My dad has one that looks very similar to that one. He was very proud of having a torch that needs no batteries. I looked inside and guess what- I found two lithium coin cells (non-rechargeable type) hidden inside. Quote Link to comment Share on other sites More sharing options...
Sukhbinder Posted December 7, 2005 Author Report Share Posted December 7, 2005 Same was the case with me Ldanielrosa. i found two lithium coin cells in mine. There was coil in it but it was not connected and for the magnet they just put in a metal stud. these cheats... they sure dupe the customers well. >:( Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 7, 2005 Report Share Posted December 7, 2005 I tried one in the store. I shook it until my arm fell off then it lighted dimly for a few seconds.I didn't see any battery inside, but if it had one then it must have been dead like my arm.The new ones have a crank-driven generator. I didn't try it. ;D Quote Link to comment Share on other sites More sharing options...
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