DIY LEDs - The write-up

[adova]

It is not really a matter of a better choice, but what you plan on using to dim it. a "D" uses a 1-20 v power source to control dimming and can be used with a controller like the Reefkeeper Elite or lite. The other uses a POT to control dimming (from what I understand). I went with the "D" to leave myself more flexible...

 

[der_wille_zur_macht]

I have 5 large heatsinks that will cover about the entire surface of my bowfront tank. Should I use them all and spread the 104 leds (39 cool white XP-G, and 65 RB XP-E leds) about 3.5 to 3.75 inches apart over the entire surface of the heatsinks. Or should I use only three and group them tighter The tank is 48x24 at the widest point and 29 inches deep. The heatsinks are 8.5 inches wide and the longest is 17 inches the shortest are 13 inches long x 2 and two that are 15 inches long. Will my choice of 104 LEDs be enough to equal my curent lighting system which is 4 x 39 w T5 actinc and 2 x 250 w HQI over driven with lumentek dimmable 400 w ballast?

Are you planning on optics? What mounting height?

I have been setting my meanwells for 1 Amp for the XR-E Cool whites. Now, I have a lot of XP-G's - do these have a higher Amp rating?

There's a difference between desired operating current and maximum rated current. The XP-Gs have a higher max rated current (1.5A) but IMHO for our needs are best run at the same currents we're used to, i.e. 700-1000mA.

Which dimmable driver is the better choice...Mean Well ELN-60-48D or the -48P??? What is the reccomended load?? Is it 12 per driver or 6?

The P-type is dimmable via PWM signal. The D-type is dimmable via analog signal. If you don't know which you need, the D-type is probably "safer." "Correct" loading is 48v max, which for most of these LEDs means 12 - 13 LEDs per driver.

 

[nitjt]

I have 5 large heatsinks that will cover about the entire surface of my bowfront tank. Should I use them all and spread the 104 leds (39 cool white XP-G, and 65 RB XP-E leds) about 3.5 to 3.75 inches apart over the entire surface of the heatsinks. Or should I use only three and group them tighter The tank is 48x24 at the widest point and 29 inches deep. The heatsinks are 8.5 inches wide and the longest is 17 inches the shortest are 13 inches long x 2 and two that are 15 inches long. Will my choice of 104 LEDs be enough to equal my curent lighting system which is 4 x 39 w T5 actinc and 2 x 250 w HQI over driven with lumentek dimmable 400 w ballast?

Yes I do think I will use optics 80 degree as for mounting I have some flexablity my hood celling is about 22 inches from the surface of the water so I go from 22 to about 6 inches.

 

[adova]

The closest thing I can find to a 10v wall wart is 12v. Can someone tell me (in detail - i.e. what specific component) how I can reduce that voltage to 10v (POT or something)?

 

[der_wille_zur_macht]

It is not really a matter of a better choice, but what you plan on using to dim it. a "D" uses a 1-20 v power source to control dimming and can be used with a controller like the Reefkeeper Elite or lite. The other uses a POT to control dimming (from what I understand). I went with the "D" to leave myself more flexible...

D-type is 0-10 volts analog.

P-type requires a 10v PWM signal. NOT a pot.

If you want to use a potentiometer for dimming, the D-type is the correct choice, since potentiometers are passive devices and essentially produce an analog signal (unless you hire someone to stand there and turn the knob on and off several hundred/thousand times per second. :lol: )

In either case, the dimming circuit is a current sink, i.e. you need to bring your own power source to the game. For people hoping to dim with a potentiometer, the proper setup is a regulated 10v DC power source (DIY'd or a 10v wall wart that actually produces 10v) and a potentiometer on it's output, feeding a signal to a D-type.

For people wanting to dim with an off the shelf reef controller, the proper choice is almost certainly a D-type, since most off the shelf controllers produce 0-10v analog on their "variable" channels (whether intended for lights or pumps).

For people DIY'ing their own microcontroller, the P-type is probably the best choice.

For people DIY'ing their own PWM source (i.e. a 555), the P-type is the best choice.

FWIW, anecdotal evidence suggests that there isn't much of a difference between the two anyways, as the P-type responds to an analog signal and the D-type responds to a PWM signal.

 

[der_wille_zur_macht]

The closest thing I can find to a 10v wall wart is 12v. Can someone tell me (in detail - i.e. what specific component) how I can reduce that voltage to 10v (POT or something)?

Search in the threads - there have been a few posts of circuits using 3-pin linear voltage regulators (i.e. LM317). It's a breadboard and a few external components (caps and resistors). Or you can use a 7810 regulator, which is harder to get but fewer components.

Or, be brave (foolish?) and just use a pot, making sure you never turn it above 10v.

 

[L98-Z]

The closest thing I can find to a 10v wall wart is 12v. Can someone tell me (in detail - i.e. what specific component) how I can reduce that voltage to 10v (POT or something)?

Why don't you just buy a 9V supply, then adjust the internal pot to put out the desired current? It won't be adjustable once set (without some work), but based on your above statement I'm assuming you're not aiming for that.

 

[der_wille_zur_macht]

Most cheap wall warts have absolutely no adjustment (internal or external).

By contrast, many "industrial" style power supplies DO have a voltage trimpot that would let you do what you're suggesting, such as this one:

http://www.mpja.com/prodinfo.asp?number=18232+PS

It's a 12v supply but very likely the V ADJ trimpot (on the left end of the product photo) would let you adjust down to 10v. Then you'd leave the power supply alone, and do any manual dimming via a pot you add between the power supply and the ELN.

All of this 10v hocus pocus can be avoided by using buckpucks, which have an onboard voltage reference for their dimming circuits. All you need to do is add a pot, or buy one of the buckpucks that comes with a pot.

 

[vthondaboi]

So what I gather from the last few posts is that there is no off the shelf power supply to use with the D type Mean Well?

I'm trying to gather components together but I'd like to manually control the whites and the blues separately using Mean Wells somehow. Any suggestions besides the Radio Shack version which I heard sometimes doesn't work well?

 

[L98-Z]

So what I gather from the last few posts is that there is no off the shelf power supply to use with the D type Mean Well?

I'm trying to gather components together but I'd like to manually control the whites and the blues separately using Mean Wells somehow. Any suggestions besides the Radio Shack version which I heard sometimes doesn't work well?

There is almost always a COTS power supply for what we're talking about here, just depends what you want to pay. It's just much cheaper to buy a 12V supply and build a small dimmer.

If you don't plan to change often, you could use a 9V supply and adjust the internal meanwell pot. Adjusting whites vs blues just depends how you wire them up.

 

[skippyreef]

Here is that array with 84 on it.

 

[kcress]

It's bright enough that the cat wants OUT!

 

[skippyreef]

I know! This is the first attempt so that is why there are so many on it. 60 degree optics for sure (ordered them and there are some on it already) and on dimmable meanwells controlled by my profilux.

 

[skippyreef]

My guess is if I hang this perpendicular to the tank I can light a 2x2 area easily.

 

[skippyreef]

This is the one with 4 rows of 12

 

[Jay1982]

Skippy, how wide is the spacing on the one with 4 rows of 12

 

[TheFishMan65]

Well I finally figured out what I want to do with my heat sinks. I cut them down (80 tooth carbide 10" blade on a table saw and a little candle wax between cuts - for those interested) so that I have just the heat sink section. I then cut out a section for mounting and super glued it on.

My plan is to drill one hole and screw the two pieces together as insurance. I will then mount that in a box. I can change the angle by where I place the screws. My plan is to tip the ones on the front so that it is away from the glass and maybe the second row also. This is just a temporary box:

Once I figure out the tip angles, lenses, and mounting height I will make something a little nicer. But as DWZm has said several times get some parts and start experimenting.
One of the things I want to try is running the ones on each end of the tank parallel to the end and tip it in some. THen run five parallel to the front of the tank and tip them so they aim for the back. This hopefully will keep a lot of the light off the glass and cut down (if not eliminate) the algae.

 

[tahiriqbal]

Do you think your super glue would stay and hold your heatsink togather under extrem heat? I think Arctic Alumina Thermal Adhesive would been another option, then again I could be wrong!


Edit......
Sorry just seen your insurance policy....lol....

 

[TheFishMan65]

tahiriqbal,

I plan to drill a hole and use a screw as added insurance. Originally I was going to screw the whole thing together. However, lining up the holes (even with a press) is awkard. I am hoping that since they are glued the drill will go right through both pieces and the screw will really be insurance.

I also do not expect a lot of heat. My earlier testing did not get the sink (on top of the LED) much higher then 100 degree farenheit, but we will see.

I am trying to make these as near identical as I can. I plan to build a spare or two then if I loose and LED I can take out the bad section and drop in the spare. Hopefully never needed, but ... For that reason I am probably over critical on some of it.

 

[hllywd]

There is almost always a COTS power supply for what we're talking about here, just depends what you want to pay. It's just much cheaper to buy a 12V supply and build a small dimmer.

If you don't plan to change often, you could use a 9V supply and adjust the internal meanwell pot. Adjusting whites vs blues just depends how you wire them up.

That's what I intend to do until I get my dimmer controls worked out, only I'm going to use a couple of the variable WWs. That way I can start low and acclimate everything. Otherwiseat, from what I've gathered, you should be able to get the correct drive current with a 9V supply.
Tim