Power supply for series LEDs

[Jyetman]

Can someone please tell me if this power supply will run one or both of these LED pads?

This is the power supply
http://www.stevesleds.com/Switching-Power-Supply-LRS-75-24_p_300.html

These are the LED pads
https://www.dropbox.com/s/8jjjikhx54cbb56/IMG_6231.JPG?dl=0

These are the pad specs
https://www.dropbox.com/s/v3p4q08u6i0dnpb/razor-led-layout.jpg?dl=0

 

[mcgyvr]

No... Thats a constant voltage power supply..
You would also need a LED driver for it like a meanwell LDD (5V PWM dimming voltage though. I think you have the VDM module right?)..

Those "specs" lack information on the number of LEDs in series and hence their forward voltage rating to choose and appropriate power supply.. However with only a few LEDs 24V is more than likely sufficient..

 

[mcgyvr]

To move forward in the most logical way this is what I need to know
How many channels of LEDs are on that "pad" as you call it..
How many LEDs per channel?
Can you draw a schematic of it?

Then
Do you want dimming?
What control voltage for dimming do you have available? 0-10V analog? 10V PWM? 5V pwm?

 

[mcgyvr]

Ok...
So looking at those images now I see this..
2 channels..
Channel A (White Channel) = 6 LEDs?
Channel B (Blue Channel) = 7 LEDs?
Is that right?
If so the forward voltage of each LED is
XTE (white) = 2.85Vf
XTE (blue) = 3.1Vf
XPE (blue) = 3.9vf
Epileds ??? 3.4Vf

Also.. What do you intend to do with these? Moonlight? Or a full light?
What do you plan on doing for heatsinking?
What current levels do you want to drive them at? I suspect they were attached to a heatsink and without that its not a good idea to drive them at their full stated current..

So... Need more information..

Found this..
Is this a correct schematic of how they are wired?

All of this is pretty important to get the proper drivers/voltage..
I'm a bit surprised by that schematic I found.. I wasn't assuming they run some in parallel.. That makes a big difference too..

And don't you have some burnt out? Need to know that too..

But it looks like we may need a 1.5-2A LED driver with a DC output voltage min of 10V that allows 1-10V analog dimming...

 

[Jyetman]

Ok...
So looking at those images now I see this..
2 channels..
Channel A (White Channel) = 6 LEDs?
Channel B (Blue Channel) = 7 LEDs?
Is that right?
If so the forward voltage of each LED is
XTE (white) = 2.85Vf
XTE (blue) = 3.1Vf
XPE (blue) = 3.9vf
Epileds ??? 3.4Vf

Also.. What do you intend to do with these? Moonlight? Or a full light?
What do you plan on doing for heatsinking?
What current levels do you want to drive them at? I suspect they were attached to a heatsink and without that its not a good idea to drive them at their full stated current..

So... Need more information..

Found this..
Is this a correct schematic of how they are wired?

All of this is pretty important to get the proper drivers/voltage..
I'm a bit surprised by that schematic I found.. I wasn't assuming they run some in parallel.. That makes a big difference too..

And don't you have some burnt out? Need to know that too..

But it looks like we may need a 1.5-2A LED driver with a DC output voltage min of 10V that allows 1-10V analog dimming...

That's close to what I was testing it with a 12 Volt DC with 2A for blue channel. I stopped using it because it gets too hot. I need a brand and type that I can buy for both channels any suggestions? Yes I like to dim the channels. I bypassed one dead epled 410-420nm dual core chip.
https://www.dropbox.com/s/qzgfactfonrg6hh/IMG_6246.JPG?dl=0

 

[mcgyvr]

That's close to what I was testing it with a 12 Volt DC with 2A for blue channel.

What PS were you using? brand/model number..
You said 9V in your other post..

But for whats posted in that picture above 2 of these would work great..
Meanwell LPF-25D-12
It will do 2.1A (2100mA) with a DC output range of 6.6 to 12V

 

[oreo57]

Those pads look like you jumpered some dead diodes.. or something "bad"..

going to throw off you calculations..

3 of your 4 violets (odd chips, usually not findable) to be exact..

Ch b will be lucky to need more than 8V...
Red is "as tested" I believe..
1500mA ldd-l @ 12v ps should do............ 12V >3A...
Oh might as well get rid of the last violet.. W/out it"s twin" the likelihood of surviving is low

bottom line 14W on white 18 on blue w/ @1.5A driver..

you can probably use a Meanwell "all in one"..@ >1.5A if you so choose..

Finding one going under 9V may be problematic and w/out the violets your blue channel will probably go under that , even at 2A.. like 7V

 

[mcgyvr]

yes if some of those LEDs aren't good anymore/jumpered then calculations will change and less current would be needed..

1500mA or less is a good idea then..

 

[Jyetman]

What PS were you using? brand/model number..
You said 9V in your other post..

But for whats posted in that picture above 2 of these would work great..
Meanwell LPF-25D-12
It will do 2.1A (2100mA) with a DC output range of 6.6 to 12V

Thank You I really do appreciate the help.

 

[oreo57]

yes if some of those LEDs aren't good anymore/jumpered then calculations will change and less current would be needed..

1500mA or less is a good idea then..

err. less voltage is needed..

@ constant current the current is a choice..
suggested 1500 LDD-L's only because of ease of obtaining and running..
A 2000mA constant current driver would be better but not so easy to get..
Well will more closely match the orig..sans damaged ones..

Current will be divided between the pairs and voltage will just add..
Fewer diodes, less voltage needed..

apologies.. didn't pay attention to your suggestion:

Meanwell LPF-25D-12

would work well esp if one needs 10V PWM or 0-10V dim..

Ldd's of course only work w/ 5-ish V PWM

2 of those $44
2 LDD's $10 plus 12V ps..

Again MAIN issue would be WHAT dim protocol one wants to use.. if any..

Still.. going to fry the violet since it is no longer paired.. Instead of 1/2 2000mA each leg it will receive full mA..
Doubt if it will survive 2000mA for very long..

They seem to brown and burn at 1000mA

 

[oreo57]

That's close to what I was testing it with a 12 Volt DC

If that was a simple constant voltage ps .. surprised you didn't pop any more diodes..

You have zero current limiting and the diodes will draw sig more than they should.
Your PS may have some current limiting ability..or you got lucky..esp. on the blue channel w/ no violets.. You pushed 2x more voltage than designed which would have really spiked your current.

 

[Jyetman]

err. less voltage is needed..

@ constant current the current is a choice..
suggested 1500 LDD-L's only because of ease of obtaining and running..
A 2000mA constant current driver would be better but not so easy to get..
Well will more closely match the orig..sans damaged ones..

Current will be divided between the pairs and voltage will just add..
Fewer diodes, less voltage needed..

apologies.. didn't pay attention to your suggestion:


would work well esp if one needs 10V PWM or 0-10V dim..

Ldd's of course only work w/ 5-ish V PWM

2 of those $44
2 LDD's $10 plus 12V ps..

Again MAIN issue would be WHAT dim protocol one wants to use.. if any..

Still.. going to fry the violet since it is no longer paired.. Instead of 1/2 2000mA each leg it will receive full mA..
Doubt if it will survive 2000mA for very long..

They seem to brown and burn at 1000mA

The violets blew out while still in the maxspect fixture way before the blue channel stopped working. When it did I simply bypassed the blue channel on the pad, swapped pad positioning and got the remaining pads up and running again. That lasted over a year until the next pad's violets blew.

 

[mcgyvr]

err. less voltage is needed..



would work well esp if one needs 10V PWM or 0-10V dim..

That one LED just has the ~700mA diodes.. so a 2A driver would overpower it if one was out as the current wasn't being split in 3 anymore and just 2..
hence.. why I said less current..

and I believe they said they had 10V analog dimming module in another post..
plus the LPF type all in one is more "newbie" friendly.. (less wiring,etc..)

 

[Jyetman]

Update, just got in my mean well LPF-25D-12 12V 2.1A 25.2W Single Output Switching with PFC LED Power Supply last week from amazon. I successfully connected it to a PWM Interface Board which is interfaced to my APEX V1/V2 ports. All is working however it only dims from 100% down to 24% which is still too bright. Any lower then 24% the LEDS flash. Is there anything I can do to bring it down further near 0%? I was thinking a small 12V cap not sure what size or if that would even work any thoughts?