LDD Drivers, why and how?

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PostPosted: Mon Jun 30, 2014 1:39 pm
So who is using/going to use the Meanwell LDD drivers? Why did you choose them over the standard drivers, and what are you doing with them?

--Colin
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PostPosted: Tue Jul 01, 2014 7:33 am
I choose them because they have a greater resolution when it comes to dimming. I built a radion clone using them.
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PostPosted: Wed Jul 02, 2014 6:59 am
I wonder if it would be worth swapping them in on a regular RapidLED (Cree) setup?

What kind of wiring do you guys use between drivers and fixtures? I've been using speaker wire but that's getting cumbersome with the number of strings I'm thinking about.

--Colin
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PostPosted: Wed Jul 02, 2014 11:52 am
You could use multi strand low voltage wire.
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PostPosted: Thu Jul 03, 2014 9:01 am
I emailed RapidLED as well to see what kind of wire they'd recommend.

I also asked about how many LDD drivers could go on their Mean Well SE-350-48 power supply. They said up to about 100 LED's (350W) and however many drivers I needed to run them. I was surprised at that answer. That makes them really economical compared to the regular ELN drivers.

Of course, if I do this, I'd need to buy an expansion module and a PWM dimming module. Might as well convert my Jaebo pumps to RA control as well. And swap out my cool white LED's for warm and neutral, add some of those lime green LED's, etc etc. Not so economical anymore. ;)

--Colin

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PostPosted: Thu Jul 03, 2014 9:03 am
cosmith71 wrote:Not so economical anymore. ;)

--Colin

LMAO :lol:
Roberto.
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PostPosted: Fri Jul 04, 2014 7:01 am
Do these use the 10v PWM or the 5v PWM expansion?

--Colin

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PostPosted: Fri Jul 04, 2014 7:53 am
You are going to run into no end of troubles if you don't start reading the data sheets for the hardware you choose and doing some research into basic electrical knowledge but I will try and help you out a bit...

cosmith71 wrote:Do these use the 10v PWM or the 5v PWM expansion?

--Colin

LDD drivers are 5v PWM.

cosmith71 wrote:I emailed RapidLED as well to see what kind of wire they'd recommend.

I also asked about how many LDD drivers could go on their Mean Well SE-350-48 power supply. They said up to about 100 LED's (350W) and however many drivers I needed to run them. I was surprised at that answer. That makes them really economical compared to the regular ELN drivers.

Of course, if I do this, I'd need to buy an expansion module and a PWM dimming module. Might as well convert my Jaebo pumps to RA control as well. And swap out my cool white LED's for warm and neutral, add some of those lime green LED's, etc etc. Not so economical anymore. ;)

--Colin

Sounds like Rapid gave you a pretty crappy answer to your question (not typically like them).
That power supply is a 7.3amp model. That means you can connect as many LDD drivers that add up to about 7amps (7x1000ma, 5x1000ma + 4x500ma, etc...) while saving the left over .3amp for wiggle room and driver consumption. It supplies 48v... The LDD drivers consume about 4v, so supplying the 48v will leave you with about 44v for the LEDs on each driver. At 1000ma a CREE XP-G has a forward voltage of 3.15v. This means that you can run 13 XP-Gs off one LDD at 1000ma (44v/3.15=13.9). So, using that power supply and 7x1000ma LDD drivers with 13 LEDs per driver you would max out at 91 LEDs.
That is a very basic explanation and I hope it helps you. Read that data sheets and gather the max amperage and forward voltages of the LEDs you will be using. Do the math and and you should be fine.
For wire choice you need to consider the length of the run and how much current will be through it. Then choose a safe gauge wire to handle it and give you the least voltage drop.
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PostPosted: Fri Jul 04, 2014 8:29 am
Thanks for the reply.

I do have basic electrical knowledge, but hadn't dug into specifics yet. I'm still trying to decide if I want to bother with the changeover from the ELN drivers or not. Nothing is set in stone. :D

So, will a LDD-1000 driver pull 1000 mA regardless of the number of LED's connected to it? I know that generally current is pulled on-demand, but LED circuits and their variable voltage needs confuse me a bit.

--Colin

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PostPosted: Fri Jul 04, 2014 8:47 am
cosmith71 wrote:Thanks for the reply.

I do have basic electrical knowledge, but hadn't dug into specifics yet. I'm still trying to decide if I want to bother with the changeover from the ELN drivers or not. Nothing is set in stone. :D

So, will a LDD-1000 driver pull 1000 mA regardless of the number of LED's connected to it? I know that generally current is pulled on-demand, but LED circuits and their variable voltage needs confuse me a bit.

--Colin

Yes, LDD drivers are constant current drivers just like the ones you are currently using, they vary the voltage. It's not too confusing, just add up the forward voltage of each LED and that will give you the voltage demand of your string, or the max LEDs per string for a given input voltage (don't forget the 4v needed by the driver). So, in short, it doesn't matter if you have 1 or 13 LEDs on an LDD, it will always supply the given amperage while varying the voltage.
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