another LED build. question on converter

[FDdragon]

ok so after reading some more and talking to some people here is what I have come up with.

Option 1. use a meanwell LPF-90D-54 (54v and 1.67a) to power some 3.6v LED with 700-750mA.
-I can run 3 strings (parallel) with 15 LED in each string. that will leave me with 556mA and 54v per string (is running lower amps good?). I can run 45 LED off this driver

Option 2. use a meanwell ELN-60-48D (48v and 1.3a) to power the same LEDs
-I can run 2 strings (parallel) with 13 LED in each string. That will leave me with 650mA and 46.8v per string. I can run 26 LED off this driver.

If this is correct, I can use two ELN drivers and have one power my blues and the other my whites (and some blues too maybe because that a lot of white)

Please let me know if this makes sense and/or if you have any recommendations. I know there are some concerns with running parallel but I will get to that after I get this part figured out. Im sure there are some errors in my options. Gotta take it a step at a time.

As mentioned in my previous posts, I am learning this stuff. Despite the confusion and all, I am having fun trying to figure this out. ha ha. Thanks

[unbereefable]

Parallel is not for beginners. The strings require balancing and the use of fuses. Balancing is checking the actual Vf of each led and making sure the strings balance out to take the power equally. Let's say you got 1 string that pulls 44V and another that pulls 35. This happens a lot. The LEDs don't all pull the same voltage. So you'd need to measure each string and pull out certain LEDs and add them to other things and vice versa to get the strings to equal out.

You also need to use fuses and resisters to make sure the power doesn't got above a certain range. If you have 3 strings each pulling 700ma, and one blows, the rest of the strings will get the other strings 700ma and split it making 2 strings get 1050ma. Putting a resistor will protect the strings from over current and fuses will, when blown will protect the entire string from blowing.

I'm pretty experienced with diy LEDs and still don't like parallel strings. Check out buying a dedicated power supply and look into LDD drivers from meanwell. The can be had for pretty cheap and by buying a nice sized power supply that leaves room for growth.

[FDdragon]

yeah, I know there are some big concerns with parallel. Electricity is all theory since things are "supposed" to work a certain way but usually don't. So I just want to see if my "theory" on these setups are correct.

i don't take electricity lightly and at least learning this on paper will get me started rather than just soldering some pieces together and hoping for the best.

So if my options makes sense then im on the right path...then it will be fine tuning (testing, wire size, resistors, fuses, etc.). once it makes sense to me, then i can look at better/safer options and know what im looking for.

thanks again for the advice.

[FDdragon]

Well im going to be moving forward with the build. Mostly because it doeant seem too difficult and it would be a fun project. If i dnt like the way it looks, i wont anyone to blame but myself.....but i will know exactly how it was put together so ill know how to take it apart dor modification. Will post pics once things start.

[FDdragon]

Poakley, i pmd you for those drivers. Hit me up a 8058145923

[xL30NxCREATORX]

I would buy any psu and use meanwell LDD and im using arduino to control it


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[DaveMorris]

Now that is a proper science project!

[FDdragon]

I looked in the ldd drivers and it looks like they are good options. I think the eln drivers might be easier to work with but I am open to the pros and cons of both...if anyone has experience with hooking both kinds.

[unbereefable]

Ldd are much better at dimming. They'll dim down to 0. The can control from 2-52V. Whereas the eln need a much higher starting V to power the LEDs. Eln 6048D is 24-48V. Meaning it needs at least 24V to actually light your string. The Ldd needs 2V. The Ldd is controllable via 0-5Vpwm. So not comparable with apex or DA products without additional of modules. Most use and arduino based controller. Coralux makes one called the storm.

[FDdragon]

It seems like a lot more work to get the same results.
So the amount of drivers i need depends on the psu correct?

I would need a lot of drivers to equal the amount of lights usinga eln driver.plus the cost of the power supply. And it seems like a lot more wiring. Not that im scared of doing the extra work but if the eln drivers work great and reduces the w work Involved while still providing what im looking for, then im good with it. I dont plan on dimming too much.,..i want the capability just in case.

Maybe im seeing it wrong.

[FDdragon]

I got two ELN drivers to start my build and they will be running 26 LED per driver. got a few things to get in order to start the build but will post pics and progress along the way. Will probably be looking for a few more drivers in the near future.

Thanks poakley for the hookup!

[DaveMorris]

Don't forget that it is very easy to overheat the LEDs when you are soldering them. You won't want to use a "my first soldering iron" to connect the LEDs. I would invest in a nice, controllable iron so you don't cook your LEDs. Also, after connecting the LEDs check, recheck, and then check again that all of them are connected with the correct polarity. It only takes a couple seconds for a reversed diode to burn out.

One last caution...I haven't heard you talk much about a heatsink. This is absolutely crucial if your LEDs are going to last more than about a week. You need a good and efficient heatsink to attach the LEDs to in order to keep them cool. Make sure that you are using a good thermal paste or adhesive to attach the LEDs to it. LEDGroupbuy.com sells some great heatsink kits. Check them out. Here is a link to my build thread where I am showing my Makers LED project for my fuge. The heatsink kit was only $49.

http://www.sdreefs.com/forums/showthread.php?103096-My-300g-to-120g-Upgrade/page10

Here is the thread for my larger display tank LED build:

http://www.sdreefs.com/forums/showth...ank&highlight=

[unbereefable]

Ledgroupbuy heatsink is probably one of the best looking "finished" heatsink to can buy. It's what I'm using on my build. But they're not cheap. 24" will run $100. But they come with screws, fans and splash shield. A cheaper alternative is to use aluminum C channel. I'd run some 1.5". Depending on spacing and drive current you might not even need fans. Well that was my case anyway. But I must warn you, lesser quality LEDs tend to run hotter. What brand LEDs are you using?

And yor right about the ELNs being cheaper up front. The great thing about ldd is that they're a super cheap when building bigger fixtures. Buy a power supply and 10 ldd. If you buy a good quality power supply it will run around $80. Plus $5-$7 for the ldd. Now you can control +- 140 LEDs for about $130-$150. And the ability to control individual strings and not mess with the extra work involved with parallel strings. But I have a reef angel control which is is capable of 0-5V pwm with no addition modules.

But if you're able to master the parallel string, everything else will be cake. Check rapid led website. Sometimes they sell refurbished ELNs for $20/each. Or $22.

[FDdragon]

cool, thanks for the info. I got a friend who is going to be giving me some free LEDs so ill see what he has. I don't think running the parallel strings would be that difficult but will take my time to do it right.

and yeah, im definitely going to be researching the best options for cooling my system down. I think ill have easy access to some C channel but if the ledgroupbuy comes with all the goodies then I might consider it. I was thinking about gluing the LED in place but am really leaning towards screwing them in....that way if something were to happen I can easily take them out. it might take a while to drill all those holes but I don't mind.

once again, thanks for the info and advice. will keep you guys updated when I start.

[DaveMorris]

You can use the Aquarium Controller interface that Stevesleds sells to convert a controller output to PWM if thats what you have.