Meanwell LDD driver: for those who want to dim to 0 using Arduino

[Colin]

I haven't been able to find a good answer for this question.

If I run a LDD-1000 with only 5 or 6 LED's, how much current does it pull from the power supply? The spec sheet says 900mA MAX, but what I'm wondering is if it will pull less with less load applied. I'd like to run several LDD's at varying LED loads (different color channels).

So, with 10 LDD-1000's with 5 or 6 LED's on each, would this still require 9A from the power supply, or would it scale down to about half that?

Thanks,

--Colin

 

[O2Surplus]

I haven't been able to find a good answer for this question.

If I run a LDD-1000 with only 5 or 6 LED's, how much current does it pull from the power supply? The spec sheet says 900mA MAX, but what I'm wondering is if it will pull less with less load applied. I'd like to run several LDD's at varying LED loads (different color channels).

So, with 10 LDD-1000's with 5 or 6 LED's on each, would this still require 9A from the power supply, or would it scale down to about half that?

Thanks,

--Colin

My guess answer to your question is yes- to a point. I've noticed from my own tests on LDD's that "Current In" is < "Current Out". Your short strings with a lower total Vf will demand less current from the power supply. Of course, the only way to know for sure is to take a current measurement from the supply side of the circuit to know for sure. Run the test using a string with the highest total Vf as your reference. Multiply the current reading X 10 and use the product as your maximum total current draw from the supply. If it's 80% or less than you supply's Max- then you're good to go.

 

[zachts]

The other way to size the string is to use the total wattage of the LED strings when using the LDD driver. add up the vf of each string including the 3 or 4 volts for the LDD and multiply by the current (1000mA would just be multiplied by 1) then add up all the strings and size your supply such that you are only useing about 80% of its rated wattage.

 

[Colin]

The other way to size the string is to use the total wattage of the LED strings when using the LDD driver. add up the vf of each string including the 3 or 4 volts for the LDD and multiply by the current (1000mA would just be multiplied by 1) then add up all the strings and size your supply such that you are only useing about 80% of its rated wattage.

That's my basic question. Can a LDD driver pull less current from the power supply than it's rated output? I.e., will a half-loaded LDD-1000 only require 500 mA from the power supply instead of the 1000 mA it outputs?

This makes a difference because if that is not true, you would be limited to a certain number of LDD drivers on a given power supply regardless of how many LED's are actually hooked up.

By your method, a LDD-1000 with 5 LEDs with 3.5 vf at 1000 mA would require 20.5 Watts (counting the 3 volts for the LDD). A 48v power supply would then have to supply 0.43A @ 48v to provide the 20.5W.

That would mean a 7.3A/48v power supply could handle ~14 LDD-1000's with 5 LED's each. Correct?

Thanks for the response,

--Colin

 

[O2Surplus]

That's my basic question. Can a LDD driver pull less current from the power supply than it's rated output? I.e., will a half-loaded LDD-1000 only require 500 mA from the power supply instead of the 1000 mA it outputs?

This makes a difference because if that is not true, you would be limited to a certain number of LDD drivers on a given power supply regardless of how many LED's are actually hooked up.

By your method, a LDD-1000 with 5 LEDs with 3.5 vf at 1000 mA would require 20.5 Watts (counting the 3 volts for the LDD). A 48v power supply would then have to supply 0.43A @ 48v to provide the 20.5W.

That would mean a 7.3A/48v power supply could handle ~14 LDD-1000's with 5 LED's each. Correct?

Thanks for the response,

--Colin

Remember- The LDD's efficiency drops with lower led counts per string. That's why I mentioned in my previous post that you'll have to do some current measurements to know for sure what the "real" current draw is.

 

[Colin]

I ordered one to play around with. We'll see.

Thanks,

--Colin

 

[saf1]

Yeah, that is what I am doing also Colin I just ordered a pair of Borealis Luxeon chips from Rapid with some LDD's to test out a new fixture I'm thinking of. The challenge with the chip is that there are 4 different channels 2 of which run at 1000mA max and another pair running at 700mA max. Seemed like a good combination when paired with the Mean Well SE-350-48. I'll know more next week I guess.

 

[vpaul79]

It's based on voltage. An LDD driver will draw 1000mA from the power supply when it reaches it's max rated voltage. A LDD 1000 has a rating of 52v, you will need to account 3v for the driver itself leaving 48v. If you use 5 LEDs rated at 3v a piece then you are drawing 15v to 18v or roughly 35% of it's rated capacity. Therefore you will only draw 350mA from the power supply.

 

[Colin]

It's based on voltage. An LDD driver will draw 1000mA from the power supply when it reaches it's max rated voltage. A LDD 1000 has a rating of 52v, you will need to account 3v for the driver itself leaving 48v. If you use 5 LEDs rated at 3v a piece then you are drawing 15v to 18v or roughly 35% of it's rated capacity. Therefore you will only draw 350mA from the power supply.

BINGO! That's what I've been wanting to know!

Thanks!

--Colin

 

[oreo57]

It's based on voltage. An LDD driver will draw 1000mA from the power supply when it reaches it's max rated voltage. A LDD 1000 has a rating of 52v, you will need to account 3v for the driver itself leaving 48v. If you use 5 LEDs rated at 3v a piece then you are drawing 15v to 18v or roughly 35% of it's rated capacity. Therefore you will only draw 350mA from the power supply.

THAT is completely wrong..............

The LDD will output 1000mA REGARDLESS of the number of LED's in series.. 1 or 12.. same 1000mA..Only the V(out) changes...........

 

[Colin]

THAT is completely wrong..............

The LDD will output 1000mA REGARDLESS of the number of LED's in series.. 1 or 12.. same 1000mA..Only the V(out) changes...........

We know this. I'm concerned with INPUT, not output.

--Colin

 

[jedimasterben]

THAT is completely wrong..............

The LDD will output 1000mA REGARDLESS of the number of LED's in series.. 1 or 12.. same 1000mA..Only the V(out) changes...........

They're talking about input current, not output.

 

[perkint]

As O2Surplus said, the LDD will generally draw the power from the supply (eg 50V and 0.3A to give 15W roughly from a 50V supply) that it needs for the LEDs (5 times 3V at 1A so 15W) but you then have the power draw of the LDD itself, but this will vary depending on the input voltage and output voltage. In the above mentioned figures, and LDD would draw more power (from a 50V supply) than if you fed it a 18V supply.

Hopefully that makes sense...

Tim

 

[Colin]

Yeah, that is what I am doing also Colin I just ordered a pair of Borealis Luxeon chips from Rapid with some LDD's to test out a new fixture I'm thinking of. The challenge with the chip is that there are 4 different channels 2 of which run at 1000mA max and another pair running at 700mA max. Seemed like a good combination when paired with the Mean Well SE-350-48. I'll know more next week I guess.

Those are some interesting boards. I like the idea of the lime LED's. I may incorporate some into my RapidLED retrofits.

--Colin

 

[Colin]

As O2Surplus said, the LDD will generally draw the power from the supply (eg 50V and 0.3A to give 15W roughly from a 50V supply) that it needs for the LEDs (5 times 3V at 1A so 15W) but you then have the power draw of the LDD itself, but this will vary depending on the input voltage and output voltage. In the above mentioned figures, and LDD would draw more power (from a 50V supply) than if you fed it a 18V supply.

Hopefully that makes sense...

Tim

It makes perfect sense. I'd been given some incorrect information that confused me. I'm better now. :thumbsup:

I really don't need to replace my ELN drivers, but I think it would be a fun project.

--Colin

 

[saf1]

Those are some interesting boards. I like the idea of the lime LED's. I may incorporate some into my RapidLED retrofits.

--Colin

Yeah, will see how they work out. I was actually building something totally different when I stumbled across these. I was building the standard royal blue, white with an additional middle row that would incorporate some UV, lime, and red on a different channel to dim accordingly. Then I saw this and figured I'd give them a try.

About 100 dollars more than what I wanted to spend but I am pretty sure I can re-use them and they will be more then enough light. Probably more than since the pair will be over a 40 breeder. I'm combining two 29 gallon bio-cubes that use LED's and I like the current PWM and power control I have. I think these will work.

 

[vpaul79]

I got my information from a chain of emails with Led Group Buy. On their FAQ sheet, it states a 180W 3.75A PS can power 2 Lumia 5.2's. However, 2 channels need to run at 1000mA and 3 channels at 700mA. That would mean the PS would need at least 4100mA (4.1A) to supply the demand of the 5 drivers if they drew at their rated capacity at all times. So I questioned them how it is possible to provide less amperage from the power supply than the drivers demand. I was told that do not look at amperage when considering power, pay attention to watts. He then continued with the following statement:

The longer version of that is that an LDD driver that is rated for 1000mA will not pull 1000mA from the power supply at all times, it depends on how much voltage the LEDs will be using. The output of the LDD is ~45v, and if you were running the full 45v of LEDs then you would pull 1A from the power supply, but if you were only pushing 12v of LEDs, then the LDD would take another 3v from the 48v input, and it would convert the remaining 33v into the output current. The 15v total used is around 31.5% of the total voltage (48v), so it will only pull 31.5% of the current, so ~315mA instead of the full 1000mA.

From that statement it looks like the amperage of a power supply is not the limiting factor, but the total wattage being pulled from the LED's themselves. So if someone wants to hook up 9 LDD-1000 channels, but only uses 15v per channel, does he need a 9A PS, the answer is no.

 

[proietti]

THAT is completely wrong..............

The LDD will output 1000mA REGARDLESS of the number of LED's in series.. 1 or 12.. same 1000mA..Only the V(out) changes...........

Totally agree. The LDD will output its stated Amps regardless of the voltage. The input voltage changes the Watts. Ohms law.

 

[Geoff1969]

Help neede with controlling my LED drivers with Arduino

Help neede with controlling my LED drivers with Arduino

I want to control my led's and drivers with my arduino. I Have: Maxwellen Dimmable Constant current LED Driver 7-12 pcs x 3w 36w running 10 x 3w Warm White led's. Maxwellen Dimmable Constant current LED Driver 7-12 pcs x 3w 36w running 8 x 3w Blue led's. Maxwellen Dimmable Constant current LED Driver 12-20 pcs x 3w 60w running 20 x 3w Cool White led's. Maxwellen Dimmable Constant current LED Driver 15-30 pcs x 3w 90w running 30 x 3w Cool White led's. Dimmable Constant current LED Driver 3-5 pcs x 3w 15w running 5 x 3w Red led's. Dimmable Constant current LED Driver 3-5 pcs x 3w 15w running 5 x 3w UV led's. I want to control these with my Arduino Mega 2560 but the power required for each driver is different and higher than the arduino can handle. Wow would I do this?

 

[proietti]

I want to control my led's and drivers with my arduino. I Have: Maxwellen Dimmable Constant current LED Driver........

controlling them with an Arduino is going to be hard. As I understand the Maxwellen dims with a potentiometer and not a PWM signal or a 1-10 signal. I might be wrong but early on when I looked at these that is what I was told.