10W LED chip on 7W LED driver?

primuspaul

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Jan 25, 2018
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What happens if I hook up a 10W LED chip to a 7W LED driver? The voltage of the driver is within the specs of the LED chip (12V), but obviously the driver is underpowered. I'm thinking one of two things will happen, but don't know which:

1. The driver will simply provide insufficient current/voltage to run the chip at full brightness, but neither component will break.
2. The LED driver will provide full brightness to the LED chip until the driver overheats and breaks.
 

parametrek

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The first one. You may notice a slight change in tint form the LED but everything should be fine as long as the voltages line up and the driver is a constant current driver. Where as LED strip drivers are usually constant voltage and in that case things are more complicated.
 

primuspaul

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The first one. You may notice a slight change in tint form the LED but everything should be fine as long as the voltages line up and the driver is a constant current driver. Where as LED strip drivers are usually constant voltage and in that case things are more complicated.
Good. I heard reports of driver "resetting" resulting in an annoying flicker rather than a dimmed, but constant LED glow.

I was actually trying to save $ by getting a cheaper, lower wattage driver and at the same time increasing LED chip life by reducing power/light/heat. I guess I'll try it since you're saying that's basically what will happen.
 

Julian Holtz

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I was actually trying to save $ by getting a cheaper, lower wattage driver and at the same time increasing LED chip life by reducing power/light/heat. I guess I'll try it since you're saying that's basically what will happen.
This is what will happen. Since chinese high-power LEDs are quite cheap, I only run them at half the rated power. In my desklamp, I run the 50W chips at 20W.
http://www.candlepowerforums.com/vb...IS-desk-lamp-modding-with-2x-50W-Epistar-LEDs
This way, they run more efficient and last for ages. The driver does not care much. As the Vf of the led is a little lower at lower currents, the driver has to work a little less hard, so it's win-win for both components.
 

MeMeMe

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Aug 27, 2018
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No.It only means the LEDS will be at"70%" 'brightness'

Well not that is not really true. The driver is 7W and has a voltage range that covers the LED, so the maximum driver voltage (at which it will be rated 7W) is likely to be higher than the voltage at which the LED has a 10W rating ... which is of course at best nominal. The brightness will be < 70%. How much? Impossible to know without knowing the drivers output current.
 
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