Minimalistic multichip DIY LED build

[bemenaker]

OK, I've been following this, and even posted a comment about the MW drivers from their datasheet, but now it's time for me to ask a question about my intents.

I picked up a 50W hybrid epistar (20K) and a dimmable driver from AC-RC on ebay. This is going into my wife's old 65 Gallon we are setting up. The original light hood had a 175W (i believe) MH in the center, and then there are two power compacts lights along the front and back edge of the hood. What my intent is, is to replace the MH with the 50W led, and leave the two PC's. Most likely running the PC's most of the time, and the LED for shorter duration in the middle, maybe doing that vice-versa, not sure yet.

Is this enough light? or do I need more led's to make up the for the MH? I do have a 90 deg lens for the LED if necessary.

Edit:
Wife isn't ready to go all LED yet, partially do to the disco effect, and partially do to caution of something new. Though, we have talked about adding a couple of purple/red/greens, for even more color pop.

 

[Lassef]

@ TopTrea: Mayby I´m a silly Swede with low understanding of the english language but I do not understand this, please explain

But if a Diode opened up the current would flow through 3 diodes at a higher total resistance and the driver would try to put out more voltage to compensate for the lower resistance still driving the same current

Still with all of the measurement I have done with this type of chip´s I should never by myself put a parallell conection without fuses - even if I run them i a lower current than max. The FV:s I have meassured in similar chips differ to much. I allways try to avoid parallell conections. Maglofsters run parallell conection but his chip manage to take the whole current if one break.

Sincerely Lasse

 

[Lassef]

I recently bought an epistar hybrid 100W LED off ebay (blue/white mix) and hooked it to a meanwell HLG150-42B. It's absolutely great, dims off my Apex just perfectly, and runs very cool. I set it on an old tower-style heatpipe heatsink I had lying about, and suspended it from the ceiling. I've tested with multiple temp sensors, and it runs around 32-35 C.

I'm very happy with it. Only thing I noticed that seems odd, I'm only pulling 0.8 amps at full power. That seems a little low to me. Quick math shows it should be pulling more amps.

Sounds strange. Have you put your current meter in serie with the circuit (plus from the meter to plus on the driver and minus from the meter to plus on the chip and minus from the chip to minus on the driver) and do you use the 10 A mode on the meter? This driver should give arround 4.2 A in constant current mode.

If you suspect some wrong with the dimming - test with a 9 V battery at the 1-10 V inlet to the driver.

The temperature is not so strange - with a processor cooler with heatpipes I have the same temperature as you - heatpipes is very effective!

Sincerely Lasse

 

[Lassef]

OK, I've been following this, and even posted a comment about the MW drivers from their datasheet, but now it's time for me to ask a question about my intents.

I picked up a 50W hybrid epistar (20K) and a dimmable driver from AC-RC on ebay. This is going into my wife's old 65 Gallon we are setting up. The original light hood had a 175W (i believe) MH in the center, and then there are two power compacts lights along the front and back edge of the hood. What my intent is, is to replace the MH with the 50W led, and leave the two PC's. Most likely running the PC's most of the time, and the LED for shorter duration in the middle, maybe doing that vice-versa, not sure yet.

Is this enough light? or do I need more led's to make up the for the MH? I do have a 90 deg lens for the LED if necessary.

Edit:
Wife isn't ready to go all LED yet, partially do to the disco effect, and partially do to caution of something new. Though, we have talked about adding a couple of purple/red/greens, for even more color pop.

I should use the lens in this case. What is the current of the driver? How is the tank - is it a cube or a "normal" tank?

Sincerely Lasse

 

[Lassef]

Is there a driver that can run several 100 watt leds?

In parallell conection yes - in serial conection - I have not find any.

Maglofster have his two 100 Watts epistar chips in a parallell conection with a driver that gives 6 A. Each of this chip manage 6 A so there is no risk if one of them break. He runs them at 50 % of their capacity.

Sincerely Lasse

 

[garbled]

I should make a note here, when I say 0.8 Amps, I mean from the mains. 125VAC @ 0.8a. Which is why you (and me too before I realized my error just now) came up with 125 volts at the rail. My DRIVER is pulling 0.8a@125VAC, and in theory, thats 100W, which it translates into.. hrmm.. 2.77a on the LED line.

I need to get one of those inductive testers to see if thats about right. Do those work for a DC load? If not, I'll use my multimeter set for high amps. That always scares me though.

Interesting that my 150w driver is only putting out 100w. I'm slightly confused by that still. I expected an amp draw at the wall, of like 1.3-1.7ish.

 

[Lassef]

The data sheet says 1.7A / 115VAC for this driver

Sincerely Lasse

 

[kentrob11]

Whelp, got my power supply and heatsink in...Now just waiting for the chip. On a side note, If I just wire the chip up without my reefkeeper ALC will it simply run the chip at the max wattage the power supply puts out?

 

[Dustin1300]

Whelp, got my power supply and heatsink in...Now just waiting for the chip. On a side note, If I just wire the chip up without my reefkeeper ALC will it simply run the chip at the max wattage the power supply puts out?

If it has 0 volts, from my understanding it will not light.

 

[garbled]

OK, built up my courage, stuck the multimeter inline:

Full on- 4.52 Amps 17 volts?!

Worth noting, the LED turned on when the multimeter was setup for amps, but stayed dark when setup for volts. Not sure why.

However, running at full amps and half voltage would be somewhat consistent with my results of only seeing half the expected amp draw at the wall. I wonder why the voltage is so low? It's only connected to the one LED, straight shot.

HLG-150H-36B, so, I expect 4.5A @ 36v... I see nothing in the spec sheet that would lead me to believe otherwise.. Unless running the multimeter inline only measured half, but, that seems odd/unlikely.

 

[maglofster]

Maybe you are doing something wrong with the multimeter?

Current is measured "inline" in the circuit. Voltage is measured between two points "parallell" like + and - on the led you are powering. There are also a lot of settings on most multimeters.

http://www.ladyada.net/learn/multimeter/voltage.html

Also, you will not get exactly what it says on the spec sheet, normaly you get about 90% of what it says.

 

[lookout888]

Getting penetration is ususly done more with the usage of lenses than anything else. Whit the higher powered LED you can use a tighter lens and have the lights higher to mantain a more equil level of light difference between the top of the tank and the bottom. However lenses also have the negative effect in my mind of creating shodows compared to a greater number of light sources.

I personly use the 3 to 5 watt LED's on tanks up to 24" deep. I initialy used 60 degree lenses but the shadowing effect I did not like and it convinced me to go without Lenses. Your tank is over 24" deep so stronger LED's with lenses will probably work much better for you. But keep in mind each light is a point light source. The more light sources that his a particllar pint in your tank the less likely you will have a shadow issue. Also when you have different LED's at different spectrums the more likely you will notice there shadows. As an example a particlur point in the tank might be in direct line with 2 different royal blue LED's but the white LED is shaded from that point so the shadow of the white led will look bright royal blue.

Thank you for your reply... It make sense and still unsure of what way i want to go. Can anyone point me in a direction of a driver that is dimmable via pwm and can drive one 20w led. I am having a hard time finding a reasonable one. here is a link to the led. http://www.ebay.com/itm/EPISTAR-20W...106?pt=LH_DefaultDomain_0&hash=item3f1220058a
Thanks
Mike

 

[garbled]

Oh, voltage is measured parallel? Oops, I tried inline. Time to try again, and this time, hook up the killawatt to make sure I'm measuring the wall pull right.

Lookout - I'm staring at some meanwell specs.. not sure.. the HLG-40H-12 (which is the smallest HLG) puts out 3.3A @ 12v, which is slightly too much maybe?

An ELN-30-12 puts out 2.5A at 12v. My ELN has potentiometers internally, so you could easily set that down to 10-11v, and 2amp max if you wanted. The HLG's are dimmable, but do not have the potentiometers like the ELN's do. There is also a 9 volt version, if the 12volt one scares you.

There is also an LPF-25D-12, again, 12 volt, but 2.1 amps, and works with all dimming types. (I'm a big fan of the HLG style three way dimmer systems on some meanwell equipment. I can test with a potentiometer, then hook it up to my apex. I've tested my HLG with all three, and it worked)

 

[TropTrea]

I should make a note here, when I say 0.8 Amps, I mean from the mains. 125VAC @ 0.8a. Which is why you (and me too before I realized my error just now) came up with 125 volts at the rail. My DRIVER is pulling 0.8a@125VAC, and in theory, thats 100W, which it translates into.. hrmm.. 2.77a on the LED line.

I need to get one of those inductive testers to see if thats about right. Do those work for a DC load? If not, I'll use my multimeter set for high amps. That always scares me though.

Interesting that my 150w driver is only putting out 100w. I'm slightly confused by that still. I expected an amp draw at the wall, of like 1.3-1.7ish.

Samoe thing to keep im mind when your measuring the input to your driver. While it is a 150 watt driver it will only draw 150 wat the wall if you outputing the max.

To measure the output the simplest and safest way is to witre a 1 ohm resitor in line with your lead. With the one ohm resistor if you measure the vlotage across it it converts driectly to current being drawn through the circuit.

Examples:
800 mv / 1 Ohm = 800 ma
1.3 Volts / 1 ohm = 1.3 Amps.
1.7 Volts / 1 ohm = 1.7 Amps.

Then voltage can be measured directly accross your LED array. If you want to see what wattage your array is actualy running at simply multiply the measured voltage across the arrray and the current you measured across the resistor.

Examples:
400 ma X 26 Volts = 10 Watts
800 ma X 28 Volts = 22 Watts
1,000 ma X 30 Volts = 30 Watts
2,000 ma X 32 Volts = 64 Watts
3,000 ma X 34 Volts = 102 Watts
4,500 ma @ 36 Volts =162 Watts

Note thiese numbers are basicly pulled from a had since I do not know exactly what LED chips they are using in this array and how they they have the array wired. The manfacture spec on the array is very vague. But if you plot out different setting with your controler you should see a definate patern.


Measuring the input to the Driver will drive you crazey. But if do you will find the drivers work more effeciently the closer they are to max voltage and current rating. What happens is they work as a sink to utalize the unneeded voltage which is actualy wasted power. So a 60 Watt Driver will be much more effecient for a 50 watt LED array compared to using a 150 Watt driver on the same array.

 

[bemenaker]

I should use the lens in this case. What is the current of the driver? How is the tank - is it a cube or a "normal" tank?

Sincerely Lasse

My post from last night didn't post, odd, but oh well...

The driver I am using is the 50W dimmable that AC-RC on ebay sells. It's 30-36V 1.6A.

The 65 Gallon is a "standard" it's 19wx36Lx24d inches.

I had assumed I would need the lens, but never hurts to ask people that know more than me.

Thanks for advice.

 

[Landsailor]

Oh, voltage is measured parallel? Oops, I tried inline.

Voltage is just the potential difference between two points.

You can measure voltage in series but it's not necessary nor convenient. Current has to be measured either in series or by using a current clamp.

You might have seen some DIY designs that use a large resistor as a current sense resistor. You get a voltage across the known resistance that is equal to the current. However, you are still physically measuring voltage with the meter.

http://www.radio-electronics.com/info/t_and_m/digital-multimeter/dmm-basics-tutorial.php

 

[Lassef]

Whelp, got my power supply and heatsink in...Now just waiting for the chip. On a side note, If I just wire the chip up without my reefkeeper ALC will it simply run the chip at the max wattage the power supply puts out?

Some dimmable drivers will run at max if you do not put in any signals, some will not. How your works - you have to test. If it does not lihgt with no signal, put a 9 V battery at the 1-10 V input.

Sincererly Lasse

 

[Lassef]

Thank you for your reply... It make sense and still unsure of what way i want to go. Can anyone point me in a direction of a driver that is dimmable via pwm and can drive one 20w led. I am having a hard time finding a reasonable one. here is a link to the led. http://www.ebay.com/itm/EPISTAR-20W...106?pt=LH_DefaultDomain_0&hash=item3f1220058a
Thanks
Mike

ELN-30-15P will work - it will adjust the voltage output to the FV at 2A. it is also possible to adjust the current to 1.9 a if you want.

The ELN-30-12P will also work but you must adjust the output current to 2A or lower with the adjustment screw inside before you conect the LED. The max output is 2,5 A which is to much.

Sincerely Lasse

 

[Lassef]

My post from last night didn't post, odd, but oh well...

The driver I am using is the 50W dimmable that AC-RC on ebay sells. It's 30-36V 1.6A.

The 65 Gallon is a "standard" it's 19wx36Lx24d inches.

I had assumed I would need the lens, but never hurts to ask people that know more than me.

Thanks for advice.

I know that at a height of 50 cm (20 ") gives a 60 degree lens, a round light pattern with a diameter between 60 to 80 cm (23.6" to 31.5 ") A larger distance gives a larger circle. A 90 degree lens also provides a larger circle. you will get some light on the front and the rear window but I firmly believe that you will cover the entire length of the aquarium if you are hanging the headlight 10 - 15 cm (4 "to 6") above the surface.

Sincerely Lasse

 

[garbled]

So to bring my amp draw saga to a silly close, I hooked up a kill-a-watt to the driver today, and took a direct measurement of the draw at the wall. 1.3A, 154W at the wall. I guess what that tells me is that the amp measurement on an Apex is possibly not as accurate as one would hope. (it was off by 0.5 AFAICT)

Overall though, 1.3A is not bad given how much light this thing puts out. I'm happy. I'm seriously considering replacing my 400W MH with two of these. Not having to fight the heat all the time would be nice, and, yay computer controlled dimming.