100 Watt LEDs?

Audioguru

Joined Dec 20, 2007
11,248
My electrical utility company gave away compact fluorescent light bulbs for free. Of course they were made in China.
They were all recalled because the manufacturer copied the certification label of a competitor. Some of the lights dripped burning plastic.
 

Thread Starter

Metalmann

Joined Dec 8, 2012
703
My electrical utility company gave away compact fluorescent light bulbs for free. Of course they were made in China.
They were all recalled because the manufacturer copied the certification label of a competitor. Some of the lights dripped burning plastic.


Had not heard of that.

I'm thinking of trying out a few of the ten Watters using the steel fluorescent light fixtures themselves, as heatsinks.
Grind off the paint, and you may have a nice, wide, thin, 4 foot long; heatsink.:confused:

Will probably have to wait till the weather warms up in the Spring, though.

Don't feel much like firing up the furnace in the shop, unless I'm making money.;):D
 

takao21203

Joined Apr 28, 2012
3,702
Today I connected a Schotty rectifier, which I built the same way as the LED lamps. 4 DPAK diodes attached to a Pentium II heatsink.

It works very well, only heats up a very little, the 6 Amps diodes actually turn very hot at 2 Amps.

And I get one more volts DC.

Tested the red lamps, 4 LEDs in series, 47V- current actually is a convenient 0.7 Amps.

So I can already run them right now, don't have to wait until the new chips arrive.

The toroid also gets hot at 100W power already. Maybe I need to put a big fan in front of the toroid box.

It is interesting to do a SMPS test at this power level.

Saw some 30W LED drivers, they cost $10 something each.
So having 6 lamps, that's just an extra 60 dollar, and they can run directly from the grid.

But this circuit isn't permanent anyway. It won't be in place for many years.
 

takao21203

Joined Apr 28, 2012
3,702
I found some humor in the "Suntan" brand of caps on the power supply. Quite fitting. :D
The blue lamps really have a thermal runaway. I had to add 4 dropper diodes in series, and since they also turn hot, 2x in parallel each.

The red lamps are connected in series directly to the toroid DC, since it has dropped to 47 volts, current is 0.7 Amps. I did not power the fans, and after some minutes, it increased to 0.8 Amps.

These lamps have only 2x 10W chips on each cooler.

The other lamps have 3 chips or one 30W chip.

The blue lamp increased to more than 1.5 Amps without dropper diodes, where I stopped, and inserted the diodes.

Temperature control seems to be the key, and choosing a lower initial current. These LEDs are still very bright at 0.7 Amps!

If many are together, air temperature will slowly rise, and current will move towards nominal 1 Amps.

I made a Schottky rectifier, which works very well, only heats up a little.

In the other photos, the 30W blue lamp, and the cooling fan voltage regulator. I feed them with more than 12 volts! These fans are interesting, until 28V, speed will increase, then it will actually decrease.
 

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