Bridgelux Vero 29 Se, Possible Heat Issues, Not sure what it can be

[john073]

Good Day

I have the following setup

8 x vero29se's the 36v Version on CPU heatsinks with active cooling
2 x LRS350-36 power supplies, 9A each
1 x LRS150-12 power supply for the cpu heatsink fans

4 cobs on each power supply, currently at 35.5v

When i bump the voltage up to 36.5v where the cobs will pull more AMPs then something start smelling like electrical burn.

I am using 18awg wire with this setup

I am using that blue thermal tape between the COB and the HEATsink currently can it be that?

Thanks

 

[Ryante55]

Good Day

I have the following setup

8 x vero29se's the 36v Version on CPU heatsinks with active cooling
2 x LRS350-36 power supplies, 9A each
1 x LRS150-12 power supply for the cpu heatsink fans

4 cobs on each power supply, currently at 35.5v

When i bump the voltage up to 36.5v where the cobs will pull more AMPs then something start smelling like electrical burn.

I am using 18awg wire with this setup

I am using that blue thermal tape between the COB and the HEATsink currently can it be that?

Thanks

Pictures? Could the burning be from the fans?

 

[Ryante55]

Also wired parallel or series? I haven't messed with cobs in a while but 18a sound like alot for those

 

[john073]

Also wired parallel or series? I haven't messed with cobs in a while but 18a sound like alot for those

Nope not the fans it only starts smelling funky when i push up the volts on the 36v meanwells, at 37v the cobs are supposed to pull 2.1A each, and 4 cobs on each power supply makes that they will pull 8.4A together on the power supply that can supply 9A.

 

[john073]

Some Pics

 

[Ryante55]

Nope not the fans it only starts smelling funky when i push up the volts on the 36v meanwells, at 37v the cobs are supposed to pull 2.1A each, and 4 cobs on each power supply makes that they will pull 8.4A together on the power supply that can supply 9A.

You can adjust the voltage on those drivers? Have you checked the power draw?

 

[john073]

You can adjust the voltage on those drivers? Have you checked the power draw?

Yeah you can adjust the voltage on the power supplies a little bit about a volt or 2 yes, i must still measure the amperage usage and workout the power draw.

 

[Ryante55]

Yeah you can adjust the voltage on the power supplies a little bit about a volt or 2 yes, i must still measure the amperage usage and workout the power draw.

Some Pics

Is everything grounded? Looks like the drivers aren't on the frame maybe you just have a short somewhere? I'm not very familiar with those drivers I almost always use constant current drivers and I mount them to the frame to ground

 

[john073]

Is everything grounded? Looks like the drivers aren't on the frame maybe you just have a short somewhere? I'm not very familiar with those drivers I almost always use constant current drivers and I mount them to the frame to ground

The drives are not on the frame they are lying on a piece of wood away from the frame, not grounded no, would that be a problem?

 

[HalfBee]

The problem is the driver... the LRS-36 puts out 9A this doesn't matter if there is 1 or 5 cobs.
I ALWAYS use LDD- buck drivers to limit the current to the cobs. This lets me wire up individual
spots and not deal with parallel circuits.
(but the 3v LDD needs means having to go up to the LRS 48

 

[john073]

The problem is the driver... the LRS-36 puts out 9A this doesn't matter if there is 1 or 5 cobs.
I ALWAYS use LDD- buck drivers to limit the current to the cobs. This lets me wire up individual
spots and not deal with parallel circuits.

But wouldnt the cobs only pull the power that it needs from the power supply, like if it needs 2A on 37v wouldnt it only draw that 2A?

Thanks

 

[Ryante55]

The drives are not on the frame they are lying on a piece of wood away from the frame, not grounded no, would that be a problem?

It's better/safer to have it grounded. Also that driver will output 39.6v if you have it turned up all the way you could be using all the amps. Do not touch the fixture while it's on especially because it isn't grounded you are 1 loose wire away from getting a good shock

 

[HalfBee]

like if it needs 2A on 37v wouldnt it only draw that 2A?

Nope, not on the LRS those pump out the full current ALL THE TIME if you want to limit you need something like the LDD buck converters.
Talk to the folks over at RapidLED about that type of driver and they'll tell you why what you are doing is so dangerous.
Ran Vero 18 and 13 with LRS for years with LDD drivers...

 

[john073]

Nope, not on the LRS those pump out the full current ALL THE TIME if you want to limit you need something like the LDD buck converters.
Talk to the folks over at RapidLED about that type of driver and they'll tell you why what you are doing is so dangerous.
Ran Vero 18 and 13 with LRS for years with LDD drivers...

Thanks, ok so basicly the 4 leds will get 2.3A each now? now matter the volts i put them on, so if i push the power supply up to 37v they should still get the same amps? But i know they can handle that amps so should it be a problem?

The buck drive you are talking about can you send me a link or something so i can have a look?

Thanks

 

[HalfBee]

https://www.rapidled.com/mean-well-ldd-1500h-dimmable-driver/
That's the other thing with LDD they have 1.5A limit. But look at the other drivers the do have.
They got the data sheets there to download

 

[HalfBee]

This is an old post of Vero 18 and LRS issues...
http://www.rollitup.org/t/5h-club-leading-them-2-x-2-into-the-light.927712/#post-13170492

 

[john073]

https://www.rapidled.com/mean-well-ldd-1500h-dimmable-driver/
That's the other thing with LDD they have 1.5A limit. But look at the other drivers the do have.
They got the data sheets there to download

The problem is those ldds wont work for my setup if i want to run them at 2.1A so i would have to get totally different drives to do that, 2x480H drives possibly damn those are expensive, the vero 29 can take up to 4A each almost according to there sheet so should it be a problem? if i have 4 of them using 9A they will most like split those 9 amps if i have it right?

 

[john073]

I just tested how much amps the 4 leds are drawing on 35.5v and they are only drawing 2.5amps that they need to draw on that voltage about 700ma each, when i bumped the voltage up to 37v they draw 5.8A which sounds right aswell on 37.6v they should draw around 8A from the driver, so i am not sure if i am missing something, but it does not look like they are getting the full 9A they are only using what is needed?

Thanks

 

[john073]

So i found the problem it was the thermal tape between the heatsink and the cob that was burning, does not look like thermal tape can handle that kind of conduction to the heatsink, i removed them all and will apply thermal grease today

 

[spoonayyy]

But wouldnt the cobs only pull the power that it needs from the power supply, like if it needs 2A on 37v wouldnt it only draw that 2A?

Thanks

Correct