LED light problem, need some input.
Patrick, Wed Apr 24 2019, 06:04PMi have a great LED light that really keeps me working through the night. really punches that circadian rhythm in the gut too.
but i got the sudden flicker of death like with the florescents'. Sure enough the LEDs were fine but the driver was near death. So thinking quickly when the driver was cold and working i measured the output in parallel with the LED strip, it was 30-33 volts when steady.
The driver put out 33 volts on the label, and was rated for 10 watts, the whole fixture would get hot too.
NOW, i bought a 34 watt mean well PS. it puts out 33 volts at 1050 mA constant current.
it lights up just fine, but the LEDs on the board get hot quick, im not sure if thats normal.
ill post a pic here:
the question: is that 1050 mA CC 3 times the needed current ? (10 watts vs 30 watts.)
Re: LED light problem, need some input.
Patrick, Wed Apr 24 2019, 06:20PM
ok ill try to put the pic here :
Patrick, Wed Apr 24 2019, 06:20PM
ok ill try to put the pic here :
Re: LED light problem, need some input.
johnf, Wed Apr 24 2019, 07:23PM
Yes that is too much current
LEDs are current driven so you are over doing it by 3X
there is little difference in forward voltage drop between 10watts and 30 watts input
you need a menawell 10 watt driver
johnf, Wed Apr 24 2019, 07:23PM
Yes that is too much current
LEDs are current driven so you are over doing it by 3X
there is little difference in forward voltage drop between 10watts and 30 watts input
you need a menawell 10 watt driver
Re: LED light problem, need some input.
Patrick, Thu Apr 25 2019, 02:13AM
i was afraid of that. but this cheap original no-name-chinese one quit due to heat, im sure.
so can i use a 1/3 on 2/3 off duty cycle at 40 kHz ? or will that cause voltage spikes ?
Patrick, Thu Apr 25 2019, 02:13AM
i was afraid of that. but this cheap original no-name-chinese one quit due to heat, im sure.
so can i use a 1/3 on 2/3 off duty cycle at 40 kHz ? or will that cause voltage spikes ?
Re: LED light problem, need some input.
2Spoons, Thu Apr 25 2019, 06:39AM
No, what you want is a CC LED driver capable of up to 35V. You do not want a fixed voltage. There are loads available from china.
2Spoons, Thu Apr 25 2019, 06:39AM
No, what you want is a CC LED driver capable of up to 35V. You do not want a fixed voltage. There are loads available from china.
Re: LED light problem, need some input.
Patrick, Thu Apr 25 2019, 04:32PM
I is confused.
Patrick, Thu Apr 25 2019, 04:32PM
I is confused.
Re: LED light problem, need some input.
2Spoons, Fri Apr 26 2019, 05:40AM
LED drivers are designed to put out a fixed, constant current, regardless of the load voltage. This is how LEDs in lamps like to be driven. They generally are not built with current limiting resistors, as these waste power. LED forward voltage doesn't vary much with current (around the normal operating point), conversely applying small change in voltage result in a large change in current (the V/I curve is very steep). The forward voltage does change considerably with temperature though - so for high power LEDs (>0.5W) a constant current supply is used. That way the LEDs wont get overfed, regardless of what their Vf is doing.
2Spoons, Fri Apr 26 2019, 05:40AM
LED drivers are designed to put out a fixed, constant current, regardless of the load voltage. This is how LEDs in lamps like to be driven. They generally are not built with current limiting resistors, as these waste power. LED forward voltage doesn't vary much with current (around the normal operating point), conversely applying small change in voltage result in a large change in current (the V/I curve is very steep). The forward voltage does change considerably with temperature though - so for high power LEDs (>0.5W) a constant current supply is used. That way the LEDs wont get overfed, regardless of what their Vf is doing.
Re: LED light problem, need some input.
2Spoons, Fri Apr 26 2019, 05:45AM
Ah sorry, did not read your OP properly. I see you have a CC supply. You can probably mess with it to set the output current to an appropriate value. There will be a feedback resistor somewhere you can swap out for a higher value one - should be fairly obvious as it will be only a few ohms.
Switching the output on and off fast will probably make the supply unstable/unpredictable.
2Spoons, Fri Apr 26 2019, 05:45AM
Ah sorry, did not read your OP properly. I see you have a CC supply. You can probably mess with it to set the output current to an appropriate value. There will be a feedback resistor somewhere you can swap out for a higher value one - should be fairly obvious as it will be only a few ohms.
Switching the output on and off fast will probably make the supply unstable/unpredictable.
Re: LED light problem, need some input.
Patrick, Fri Apr 26 2019, 05:37PM
i cut the meanwell open, unfortunately , being well made its totally potted in soft silicone. so finding and modifying a resistor is a dead end.
Patrick, Fri Apr 26 2019, 05:37PM
i cut the meanwell open, unfortunately , being well made its totally potted in soft silicone. so finding and modifying a resistor is a dead end.
Re: LED light problem, need some input.
Patrick, Sat Apr 27 2019, 03:44AM
ok the silicone separates quite easily. i see aa 0.05 ohm 1 watt resistor, i think thats it.
pic:
i think i should put in a 0.15 ohm resistor? right ?
Patrick, Sat Apr 27 2019, 03:44AM
ok the silicone separates quite easily. i see aa 0.05 ohm 1 watt resistor, i think thats it.
pic:
i think i should put in a 0.15 ohm resistor? right ?
Re: LED light problem, need some input.
2Spoons, Sat Apr 27 2019, 09:47AM
That would seem about right.
2Spoons, Sat Apr 27 2019, 09:47AM
That would seem about right.
Re: LED light problem, need some input.
Patrick, Sat Apr 27 2019, 03:36PM
were going to try this :
Patrick, Sat Apr 27 2019, 03:36PM
were going to try this :
Re: LED light problem, need some input.
johnf, Sat Apr 27 2019, 07:48PM
Yes if that is the right resistor then your value is correct
try it
You have nothing to lose
and report back
johnf, Sat Apr 27 2019, 07:48PM
Yes if that is the right resistor then your value is correct
try it
You have nothing to lose
and report back
Re: LED light problem, need some input.
Patrick, Sat Apr 27 2019, 07:57PM
29.9 volts x 360 ma = 10.7 watts
ill boost the heat sink on the LEDs too. i think the cheap chinese PS took up some of its radiating ability too. which may have led to its own death.
im printing a PLA case since it seems flame resistant and ill pot it as it was in its original case in my Henkle SI 5606 silicone.
Patrick, Sat Apr 27 2019, 07:57PM
29.9 volts x 360 ma = 10.7 watts
ill boost the heat sink on the LEDs too. i think the cheap chinese PS took up some of its radiating ability too. which may have led to its own death.
im printing a PLA case since it seems flame resistant and ill pot it as it was in its original case in my Henkle SI 5606 silicone.
Re: LED light problem, need some input.
Conundrum, Sat Jun 01 2019, 01:21PM
The LEDs are *not* supposed to get hot!
Yes it sounds like the old driver had a current regulator, you could possibly use something like an LM317T in CC mode.
Conundrum, Sat Jun 01 2019, 01:21PM
The LEDs are *not* supposed to get hot!
Yes it sounds like the old driver had a current regulator, you could possibly use something like an LM317T in CC mode.
Re: LED light problem, need some input.
radiotech, Sun Jun 02 2019, 10:25AM
You need to measure the power input to the ballast at 120 volts 60 HZ with a watt meter. Your new power supply is not
a ballast.
If you reverse engineer the fixture, good luck. But that backward R U on the label means it has been tested
to prevent it from causing a number of ills, that are under the umbrella of safety.
radiotech, Sun Jun 02 2019, 10:25AM
You need to measure the power input to the ballast at 120 volts 60 HZ with a watt meter. Your new power supply is not
a ballast.
If you reverse engineer the fixture, good luck. But that backward R U on the label means it has been tested
to prevent it from causing a number of ills, that are under the umbrella of safety.
Re: LED light problem, need some input.
Patrick, Wed Jun 12 2019, 03:48AM
haven't burned the house down, been using it constantly. seems to use the right power.
Patrick, Wed Jun 12 2019, 03:48AM
haven't burned the house down, been using it constantly. seems to use the right power.
Re: LED light problem, need some input.
Signification, Sun Jul 28 2019, 05:14AM
I did something similar, and to my surprise, successfully, with a potted HeNe laser PS once...(Sam's LASER FAQ was of great help):
Can you install a good heatsink, with grease, and have metal that is well thermally connected to the main sink sticking out the sides of the re-potted, re-sealed PS? Do a good job of resealing and you can cool things many ways from outside! Remember, I don't have a great image of exactly what needs to be done.
Signification, Sun Jul 28 2019, 05:14AM
I did something similar, and to my surprise, successfully, with a potted HeNe laser PS once...(Sam's LASER FAQ was of great help):
Can you install a good heatsink, with grease, and have metal that is well thermally connected to the main sink sticking out the sides of the re-potted, re-sealed PS? Do a good job of resealing and you can cool things many ways from outside! Remember, I don't have a great image of exactly what needs to be done.
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