Des Posted April 14, 2012 Report Share Posted April 14, 2012 (edited) I bought a 12v 10watt LED light off ebay. Plugged it in and it came on and lit up the shed then burnt out i guess. I msged the seller and told them what happened and they said the light only requires 2 amps other wise it 'll burn out. Well they didnt tell me this so they have sent me another for free. What do i need to do so i don't burn the next one out ? Edited April 14, 2012 by Des Quote Link to comment Share on other sites More sharing options...
jono1986 Posted April 14, 2012 Report Share Posted April 14, 2012 (edited) Sounds like you need a resistor to limit the amount of current going through the LED, do you have a link to the ebay page? Edited April 14, 2012 by jono1986 Quote Link to comment Share on other sites More sharing options...
Des Posted April 14, 2012 Author Report Share Posted April 14, 2012 http://www.ebay.com.au/itm/260980847688?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 I don't know much about LED's but i know they suck less juice and thats what i need. Quote Link to comment Share on other sites More sharing options...
jono1986 Posted April 14, 2012 Report Share Posted April 14, 2012 Ah yeah, a car battery isn't 12volts. It's just over, and when the engine is running the voltage is at 13.8 to 14.4 which is too much for that LED. What you need is a 12V regulator or power supply....something like this would do it: http://www.jaycar.com.au/productResults.asp?keywords=mc78t12&keyform=KEYWORD&SUBMIT.x=0&SUBMIT.y=0 1 Quote Link to comment Share on other sites More sharing options...
Des Posted April 14, 2012 Author Report Share Posted April 14, 2012 Ah yeah, a car battery isn't 12volts. It's just over, and when the engine is running the voltage is at 13.8 to 14.4 which is too much for that LED. What you need is a 12V regulator or power supply....something like this would do it: http://www.jaycar.co....x=0&SUBMIT.y=0 How does that sucker wire up ? Quote Link to comment Share on other sites More sharing options...
jono1986 Posted April 14, 2012 Report Share Posted April 14, 2012 (edited) Here's a layout of the regulator itself, will have to check if other parts are needed but the basic layout is there at the moment. Just read the Data Sheet for this regulator and it states that the input voltage must remain 2.2 volts above the output voltage. You may just get away with a resistor that will drop the voltage to the LED.....will come back with a value. Edited April 14, 2012 by jono1986 2 Quote Link to comment Share on other sites More sharing options...
Jono.C Posted April 14, 2012 Report Share Posted April 14, 2012 Marty wires up a resistor in this Mighty Car Mods Ep. If it's easier to follow http://www.youtube.com/watch?v=SHiOt4hmmS4 1 Quote Link to comment Share on other sites More sharing options...
jono1986 Posted April 14, 2012 Report Share Posted April 14, 2012 Ok did a circuit in a special simulator with a resistor but the figure looks incorrect, found another regulator that will do it but will wait to see if anyone else has a better idea. Quote Link to comment Share on other sites More sharing options...
Trev Posted April 15, 2012 Report Share Posted April 15, 2012 That light is meant to run on a downlight transformer, the voltage isn't the issue so capping it won't help. Quote Link to comment Share on other sites More sharing options...
jono1986 Posted April 15, 2012 Report Share Posted April 15, 2012 That light is meant to run on a downlight transformer, the voltage isn't the issue so capping it won't help. Correct me if I'm wrong but isn't a downlight transformer just a device that converts AC to DC and changes an input voltage of 240 to 12 volts? Quote Link to comment Share on other sites More sharing options...
Trev Posted April 15, 2012 Report Share Posted April 15, 2012 Correct me if I'm wrong but isn't a downlight transformer just a device that converts AC to DC and changes an input voltage of 240 to 12 volts? Yes but also controls the amp output. Quote Link to comment Share on other sites More sharing options...
Des Posted April 16, 2012 Author Report Share Posted April 16, 2012 Yes but also controls the amp output. So what do i need to cap amps to ? Quote Link to comment Share on other sites More sharing options...
Trev Posted April 16, 2012 Report Share Posted April 16, 2012 So what do i need to cap amps to ? I would be trying to adapt it to a lighter socket plug that puts out 12v and 2amps, you can get these fairly easy, you could even get a USB car charger and modify it. Quote Link to comment Share on other sites More sharing options...
jono1986 Posted April 17, 2012 Report Share Posted April 17, 2012 (edited) did have a reply, but had to delete it Edited April 17, 2012 by jono1986 Quote Link to comment Share on other sites More sharing options...
ke70dave Posted April 17, 2012 Report Share Posted April 17, 2012 (edited) hang on a sec. it sais 10watts of power power = voltage x current 10 = 12 x Current current = 0.83 amps therefore, that light, at 12V will draw 0.83amps. you can't control the current, you can't "output 2 amps", the thing draws as much current as it needs too based on its resistance. so the selller isnt very tech savy... especially considering that it sais on the ebay advert "- Input Voltage: DC 9-12V 50/60Hz".....DC doesnt fluctuate at 50/60hz. it is the power supply that has the capacity of X amps, which allows it to draw X amps. for example, if you had a 12V power supply that had the capacity to run say...0.5A, and you connect that thing, you would likely blow up the power supply before the LED light, as the LED light would just keep drawing 0.83amps, over loading the power supply. LEDs are highly sensitive, if you have supplied it with more than 12V, which you probably have if you were using an unregulated power source, or the car battery with the engine running, thats why it blew up. jono is in the right idea with that regulator, just make sure the regulator can handle 0.83amps @ 12V and youll be laughing. pretty sweet little light though, and for 17bucks......maybe ill buy one. Edited April 17, 2012 by ke70dave Quote Link to comment Share on other sites More sharing options...
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