Recovering from a bad LED fan and heat-sink purchase

 

 

 

August 10, 2018

Ok, so you found these cooling fans and heat sinks on Ebay, 'MADE FOR 100 WATT LED CHIPS', for about eight dollars, what a deal! Well, these things were never meant to be used with LED chips. Yea, they send you the lens and reflector and show you a picture of it put all together. But if you have bought one of these, you quickly find out it was a lie.

Good news, the heat sink and fan are of decent quality. The fan blades are curved and it runs very quietly. But.....

shipped
                  fan and heatsink

You will never get this to assemble as advertised. Rather than try to get a refund I mulled over the parts and figured out how to recover from this poor purchase. First thing, push each of the screws up on the edge of your bench and snip the keepers off with a pair of dikes. Throw the springs in your spring thingy box, they won't work here. You won't need that steel bezel made to hold the lens down. There are four small tits on the bottom of the reflector, file them down until the reflector stops rocking on the LED.

Minimal tools to fix this are a coping saw and A vice would be handy. No vice? Do what you can with a clamp on the edge of your bench.

saw it

Use the lens and mark your cut. Then cut inside the mark. Role your work by quarters through your vice and this will go pretty fast. Bad photo..........

with
                  vice

Using some plastic tubing, a thin Bic pen for instance, cut four quarter inch long spacers. (Another bad pic.)

tubing

Put those spacers on the screws where the springs were, then run them up to pull your new led holder down with the all the pieces stacked like you would expect to. Smooth side must be up, the nuts are not threaded to work from the smooth side.

assembled

As you can see, I took this a bit further and tigged the power supply heat-sink and a mounting bracket to the heat-sink to make a compact package. I've seen where they vend a separate power supply for the fan. What a bulky mess. By dropping from the LED power supply to run the fan using a 7812 regulator, I've eliminated that extra power supply. It only costs ~3 watts, works for me. The wiring on the right is where I've mounted the fan's voltage regulator.

lamp

It is ok. With an eight foot ceiling you don't get a lot of coverage with this lens. But these are for my son's shop and he has 12 foot high rafters.

This was the first version

First

The pattern is much like an operating room light.

So if anything, I hope that helps with those who may have bought the 'cheap' version of the heat-sink and fan. Also, you should check your vendors LED product. As I understand it, some of these chips are whacked as far as matching the LEDs on the chip. Give the chip about a milli-amp and it should look like this:

1 milli-amp

All the LEDs should light up evenly.

 

working


I'm phasing the fluorescents out of the shop. Next, winding a 72 watt power supply for ~60 volts and adding a current limiting circuit. Six ten watt LEDs in series...

siz leds

That the spacing looks wrong is a photo optical illusion....

Thanks, Dan.

 

 

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