upgrade metal halide fixture to led

[oreo57]

Originally Posted by Jadran

This was dismissed by my tech and explained to me that it would be dumb to go that way.. because it will lower the output (32v x 2A --> 64W) .

That goes against probably 90% of those that DIY and

because it will lower the output

That is a choice based on COST alone. Plenty of AC/DC constant current drivers w/ enough amps set point to do that..
ELG-100-36 will output up to 36V (voltage ramps till Amp setpoint is reached) and 2.66 "controlled" amps..95.76W..


I've only known like one or 2 people who use "native" switching power supplies as the only "control circuit".


See given enough heat (say dead fan) and the diodes pull a lot more current at a lower voltage creating "thermal runaway" that will fry the diodes..

Basically you are just hoping the voltage runs out before the diodes go into self destruct current mode........

suppose, since I'm being picky, you barely have control in the 5 channels.. since current is shared over them w/ no accounting for differences in diode electrical characteristics..

[Jadran]

Originally Posted by oreo57

I've only known like one or 2 people who use "native" switching power supplies as the only "control circuit".


See given enough heat (say dead fan) and the diodes pull a lot more current at a lower voltage creating "thermal runaway" that will fry the diodes..

These other folks that use native ps.. what are their experiences...any long run success stories?

About dead fan and thermal runaway.. --> but weve got temp switch on each heatsink.. as soon as the temp reaches 47C it will shut down the plucks power feed...that should keep us in the clear wont it?



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[oreo57]

Sorry never kept track and most were freshwater and frankly knew the diodes were disposable at like 10/$1...

There are a lot of things that work contrary to "best practices".. just not my cup of tea.

One thing though is I consider it an obligation to mention "alternate views" to people who have little to zero understanding of what they are doing..

https://www.powerelectronicsnews.com...iver-selection

Like I said, you can "properly" run those chips but adds about $100 to the cost.
In a sense you are putting a lot of faith in very cheap components..there is very little stability to begin with..

to end this let's just say that is not the way "I'D" do it..

OK key point if one could THEORETICALLY tailor the voltage output to the chip as to only allow a safe current flow (sadly ignoring each row will be electrically different to begin with) it is possible to run err "driverless" with success both short and long term.

Problem is components never stay the same and it doesn't take much of a change to have diodes "pull" more current than they are designed for especially if you are already running at the edge.
https://www.waveformlighting.com/pcb...ting-resistors



On the upside, don't see you burning down your house...

Bottom Line:
LED devices are inherently current-controlled devices, and do not respond well to fluctuations in voltage.
If you are building an LED system using constant voltage power sources, you must absolutely be prepared to use current limiting resistors to ensure stable and safe operation of LED devices.

[Jadran]

Originally Posted by oreo57

Like I said, you can "properly" run those chips but adds about $100 to the cost.
In a sense you are putting a lot of faith in very cheap components..there is very little stability to begin with..

to end this let's just say that is not the way "I'D" do it..

OK key point if one could THEORETICALLY tailor the voltage output to the chip as to only allow a safe current flow (sadly ignoring each row will be electrically different to begin with) it is possible to run err "driverless" with success both short and long term.

Thank you for your explanations, highly appreciated. That is all very eloquently said and when layed down in such form I simply cant disagree that it is in my interest to have safe and reliable fixture. Of course it is my prespective to cut down on costs ( thats why I wont buy Giesemann or Maxspect in a first place) but not blindly and with intentional acceptance or risks. 100usd is surely gladly acceptable extra if its going to provide long life to my diodes.

it was just persented to me that drivers are not needed and the stuff that man makes speaks for itself. I dont see my friend gaining anything by ill advising me,,, thats all.

[oreo57]

He didn't "ill advise" you exactly. Just a matter of technique so to speak..