Low Voltage LED Lights Flickering

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Old 06-03-13, 07:21 PM
Justin Smith's Avatar
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Low Voltage LED Lights Flickering

I installed some 12V DC LED MR16's in some pendant lights today. Because they wanted DC, I installed a rectifier for each lamp in the canopy where the electronic transformer is. (Each fixture has its own transformer) Now I got an issue of flickering. I'm assuming I should add a resistor somewhere, but should it be before or after the xfrmr? I will be going back there tomorrow morning.
 
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Old 06-03-13, 08:07 PM
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What did you install as a rectifier.....a single diode or a bridge rectifier ?

After you rectify the A/C you'll end up with almost 17 vdc. You would need to know the wattage of the lamp to compute a resistor value and it would go between the rectifier and the lamp.
 
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Old 06-03-13, 08:49 PM
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I used a bridge rectifier and 6W lamps. The self-ballasted kind.
 
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Old 06-04-13, 12:46 AM
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If it's an "electronic transformer" as you say, you may be facing compatibility issues with the LEDs. It may be they are too small a load for the transformer to work properly. What wattage halogen bulb are the fixtures rated for?

The increased (over) voltage from the rectifying could also be causing the flickering, as a reaction from the electronics in the LED bulb.
 
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Old 06-04-13, 10:31 AM
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Justin, I would be cautious doing your own design work. Once you install anything other than UL approved products, you and your insurance company own them and any future problems. I suspect, if asked, your insurance co would prefer approved appliances. If you can't find an off-the-shelf solution, don't.

Bud
 
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Old 06-04-13, 07:50 PM
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I ended up returning the DC ones and bought some other ones which are AC rated and working fine.
 
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Old 06-05-13, 01:16 AM
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Wasn't that easy?

No rework to worry about.
 
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Old 06-05-13, 02:33 AM
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Justin, don't feel bad, I have had to avoid the quick fix so many times for the same reason. Even electronic repairs carry a risk that any component substitution other than an OEM part can lead to a liability. And they will often say it must be installed by an approved technician. I always made sure my insurance company was comfortable with my business.

What I would recommend would be continuing this at home. As a learning project, you have a problem that you need to understand more, and LEDs are going to be presenting many unique problems.

Bud
 
 

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