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Last Updated: June 06, 2011

Driving High Power Leds

High power leds from 1 watt up to 5o watts of power needs a constant current driver in order to gain a respectful efficiency, than just using those big bulky white coated limiting resistors, that not just only robs the total power of your leds, but produces poor efficiency that kills the potential of your LEDS.

A 1 watt high power leds in my opinion needs at least a 350mah constant current driver to produce its total luminance, whereas a 3 watts needs 700mah, a 5 watts needs a 1A driving current and so on and so forth.

In the picture above, is a 3 watts X 3 watts high power leds made by SEOUL semicon model P4 i ordered online. It been driven at a selectable switch in a 350mah and 700mah constant current configuration, using a switching mode type circuit. Commonly known circuit that can be used are, NCP3063 by ON semiconductor
LM3404 by national , the cheaper MC34063 by motorola...etc etc.

sample circuit as shown here:

Colliminating lens are also needed in obtaining proper beam angle of your high power leds, and also depends on your intented application..They come in a  variety of angle that will produce a narrow beam, wide beam, or spot beam.

I used the spot beam collimating lens due to the limited space of my headlight assembly as shown.

those 5mm super bright leds are for my amber signal lights.

And this is how it perform during night time and in a very dark place, with stock headlight at off position, Highpower leds at full drive settings of 700mah.

Remember to use adequate heatsink on your power leds, because of it generate enough HEAT that can destroy and or shorten the life of the led.

Prior to posting this project in my bike, its been fitted with this kind of led 2 years ago, and its working like as if it was fitted the first time.

Battery consumption was  way too low, i even tested it On for one whole day, engine off.

Just don't use resistor alone to drive this high POWER leds in order for them to last longer than the specified 50,ooo working hours. Longevity of this leds depends on the current supplied to them, Switching mode constant current driver is the only way to work on this type of leds. ARTICLES are all over the net. just browse, download and experiment.


Lawrence said...

Sir, were would I attach the heat sink? How big is the heatsink you used? Can you email me your answers sir.

THanks :)

LEI said...

every HPL has an aluminum hexagonal form heatsink to where it will be soldered like on my recent post about HPL, link is here

you can use those motherboard chipset heatsink like this one..

just attached the HPL with hex aluminum holder and your on the go