Minimalistic multichip DIY LED build

[TropTrea]

Just received my items and need help with the wiring.
Driver:
http://www.powergatellc.com/mean-well-hlg-185h-36b-power-supply.html
Led:
http://www.dealextreme.com/p/50w-3500lm-20000k-cold-white-light-led-emitter-32-36v-100744?item=6

Questions:
1. I'm wiring 4 leds in parallel, so do I put the + of the driver on the + of the first led then another wire on the + of the first led to the second led and so on

2. I'm sure I need a 1.7A quick blow fuse if so how many and does it go between the driver and first led

3. Since I'm screwing the leds to a heatsink do I need thermal grease or paste

4. Do I need to use any resistors

looking at your driver it puts out a max of 5.2 Amps. With 4 of the same LEDs in Parrellel you would have 1.3 Amps to each LED. If one LED would fail the current would be divided between the remaining 3 meaning they would jump to 1.73 Amps. Since the LED data sheet says it is designed to run at 1.7 Amps a temporary jump to 1.73 Amps should not create a problem.

With the saftey bult into running them at 1.3 Amps to start with I would not worry about either fuses or resistors.

 

[xssx]

Thanks Lassef, and TropTrea for your help

Just to be clear on the wiring I should have 4 wires coming from the + of the driver 1 for each + of the leds same with the -

 

[maglofster]

Just wanted to give a quick photoupdate on my 600 liter tank. I think the lights are a sucess for all kinds of coral so far.

I'm not going to add any substanial amounts of anything living to the tank until the summer is over and temperatures in my house stabilize again and the lights really have proven themselves.

The lights are still 300W (peak hours) and the only 200W (most of the photoperiod).

 

[Lassef]

@ TropTrea: Your calculation assumes that they have exactly the same VF in all four chip's. This is normally not the case. It may differ slightly. If the relationship between voltage, current and resistance is linear, it does not matter but a LED is a diode and then this relationship is not linear. A small change in voltage leads to a large change in resistance and hence a large change of current. Therefore, we know nothing about the magnitude of the current until we measured it to each chip. The resistance is also affected by the working temperature.

Look at this diagram for a single Cree LED (page 4, Electrical Characteristics). For example, a change of V from 3 to 3.25 V will leads to a change in current from 500 mA to 1500 mA. And vice versa. If you use 500 mA as constan current - you will have 3 V as VF and if you use 1500 mA -> FV=3.25 V


When using a constant current source and parallel connections, it is quite true that one can divide the total current, in this case, in 4 parts, but they are only equal if each chip's FV is the same. Multichip is a bit special for inside such chip there are both parallel and series connections. Reputable manufacturers use individual LEDs from the same bin in the same chip. But when you get your chip you do not know if all the chips come from the same origin bin of LED and therefore the VF can vary between different chip. If you run a single chip or chip´s i serie - it does not matter because the driver will hold the current constant (constan current driver) but if you shall distribute the drive´s constant current between two or more parallel strings - then play the single chip´s VF an important role in how the current is distributed among the chips

Most likely, it works but you can never be sure. It is best to measure individual currents of each chip and using Fuse protection. In any case, I would proceed in that way if I use a parallell conection.

@ Xssx If you do not use fuses, you can do so that you connect all plus with each other and all negative with each other by going from part to part. If using a fuse , connect one end of fuse 1 to positive on chip 1, then connect the other end of fuse 1 to positive on the driver. Do the same withh fuse 2 - 4 and chip 2 - 4.

I hope you understand what I mean.

@ Maglofster: It works well I can see

Sincerely Lasse

 

[Lassef]

I forgot the link to the Cree fact sheet Here it is

Sincerely Lasse

 

[A Reef Scene]

Could I use this heatsink http://www.heatsinkusa.com/4-230/ at 70 inches, put 6, 100 watt LED's with fans and be ok with heat?

 

[maglofster]

Could I use this heatsink http://www.heatsinkusa.com/4-230/ at 70 inches, put 6, 100 watt LED's with fans and be ok with heat?

I have exactly that heatsink, but only 48" long. I have used it for a year with 300 watt, no problem. 600W should work, but it's bound to get hot. Would it be possible to use the one 5.8" wide instead? I think that would be safer.

 

[maglofster]

Just a short video to show how my tank looks with only 200W (2x100W multichip, most of the day). Sorry for reflections, summer in Sweden = sunlight all night loong baby.. 720P For teh win..

<iframe width="560" height="315" src="http://www.youtube.com/embed/_1OLEbk-kMw" frameborder="0" allowfullscreen></iframe>

 

[A Reef Scene]

What is the K rating on your chips, and what driver are you using? Great looking tank by the way.

 

[scorphonic]

Hi everyone, I've been enjoying each and every page on this topic. I really have to thank maglofster for starting this thread, educating me in the most proficient way possible and brining some excitement into DIY for marine tanks!

I'm relatively new to the hobby of marine keeping but have been keeping tropical fish for years. My tank is only 180 liters...so would the lights below be ok to start (I have 90W T5 on there so far)? I really only want the lighting to create the shimmer effect and potentially allow me to have some softies in the tank in the next year or so.

Like a lot of other people I have the same questions regarding suitable drivers etc... I went with ac-rc for the Epistar 20W 14,000K (x4) and Epistar 20W 445nm Blue (x2) lights. I decided not to use fan assisted cooling and purchased the passive cooling heatsinks for all 20W lights. I want to now organise how I'll arrange these and will potentially mount one fan over the whole device and channel the air towards all heatsinks...have to think about this a bit more.

I purchased the following two drivers to power the whites and blue LEDs separately and even though they are rated as capable of driving 5x20w and 3x20w respectively, would it be ok to run only 4x20w (white) on the first and 2x20w (blue) lights on the last?

Finally, I've searched for an answer or step by step guide to this but how on earth do I wire up the drivers (230V mains supply) and house them (without purchasing a driver housing) so that I don't burn my house down?

For the whites:
http://www.ebay.ie/itm/220947560986?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

For the Blues:
http://www.ebay.ie/itm/270934060559?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Any advice is greatly appreciated, can't wait to get my hands on the components to give my tank a make over!

 

[lookout888]

Not sure what to get/do.

Not sure what to get/do.

Ok, So I have been reading for a while on led lighting.. I have 3w Cree led's over my tank for over a year and a half and like them.. I am getting a new tank delivered next month and am un-decided on what I want to do. The new tank
36" x 40" x 30" high.

What I was thinking is getting 4 or 5 of every 20w led with optics. (Royal blue, 20k, 16k 14k, 10k 6.5k), I was trying to find drivers to put each led on its own to allow multiple programs and flexibility. I reached out to a china company to see if they had what I am looking for and they gave me a quote of ~$700 for 25 drivers(the drivers need to be dimmable via pwm).

Then I was wondering if i should just do a few 50w's and forget about the flexibility of the 20w's. I am worried that the 20w's will not be enough to get through 30" of water. Would 4 50w's with optics be enough to cover 36x40 to start? If everyone thinks the 20's would work then I just need to see if I can find the drivers a little cheaper.

Let me know what you think.. Opinions welcome and wanted.
Mike

 

[NEReef]

I built a fixture last year with a 50W 20K led and driver off ebay. I never got the chance to set it up over one of my tanks because i sold off all of my tanks. But i just recently acquired a 350G and I am back looking into these guys as the primary light source for a 72"x36"x30" tank. Any thoughts on how many and what size 20W, 50W, 100W etc i should use?? I am thinking of doing a couple of pillar like islands in the tank and leaving the rest vacan swimming space so i dont really need full light coverage over the entire tank i could spotlight the islands and then have some lower ambient light for the open spaces.

Here are some pics and videos of my light build from last year

<iframe width="560" height="315" src="http://www.youtube.com/embed/U8eMms3JHIo" frameborder="0" allowfullscreen></iframe>

 

[TropTrea]

@ TropTrea: Your calculation assumes that they have exactly the same VF in all four chip's. This is normally not the case. It may differ slightly. If the relationship between voltage, current and resistance is linear, it does not matter but a LED is a diode and then this relationship is not linear. A small change in voltage leads to a large change in resistance and hence a large change of current. Therefore, we know nothing about the magnitude of the current until we measured it to each chip. The resistance is also affected by the working temperature.

Look at this diagram for a single Cree LED (page 4, Electrical Characteristics). For example, a change of V from 3 to 3.25 V will leads to a change in current from 500 mA to 1500 mA. And vice versa. If you use 500 mA as constan current - you will have 3 V as VF and if you use 1500 mA -> FV=3.25 V


When using a constant current source and parallel connections, it is quite true that one can divide the total current, in this case, in 4 parts, but they are only equal if each chip's FV is the same. Multichip is a bit special for inside such chip there are both parallel and series connections. Reputable manufacturers use individual LEDs from the same bin in the same chip. But when you get your chip you do not know if all the chips come from the same origin bin of LED and therefore the VF can vary between different chip. If you run a single chip or chip´s i serie - it does not matter because the driver will hold the current constant (constan current driver) but if you shall distribute the drive´s constant current between two or more parallel strings - then play the single chip´s VF an important role in how the current is distributed among the chips

Most likely, it works but you can never be sure. It is best to measure individual currents of each chip and using Fuse protection. In any case, I would proceed in that way if I use a parallell conection.

@ Xssx If you do not use fuses, you can do so that you connect all plus with each other and all negative with each other by going from part to part. If using a fuse , connect one end of fuse 1 to positive on chip 1, then connect the other end of fuse 1 to positive on the driver. Do the same withh fuse 2 - 4 and chip 2 - 4.

I hope you understand what I mean.

@ Maglofster: It works well I can see

Sincerely Lasse

I know where your comming from in this. however if all chips come from the same vendor and are even from different lots the electricical characteristice are very simular. We are driving them by controling the current not the voltage. What we are doing though is setting the absolute max limit on the voltage of the driver.

If your setting these 50 Watt Chips to run at there max rating of 60 watts I will agree with you completly you definatly need some form of protection. But running them a current where they will only draw 45 Watts each you realy have a good saftey margin. Remember there is a voltage limit adjustment on these mean well drivers.

With four LED's in parellel the current adjustment feature of the driver can maintain the voltage to hold the Diodes at that set Current. If a diode were to shorten out the voltage would simply drop to near Zero turning off all the diodes. 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. But once the adjusted max voltage was achieved which you set it would not drive beyound that. So in reality you may end up driving the Diodes at actualy a lower current.

This is the benifit of haveing a dual current regulation as well as voltage limiting factor on the driver.

 

[TropTrea]

Ok, So I have been reading for a while on led lighting.. I have 3w Cree led's over my tank for over a year and a half and like them.. I am getting a new tank delivered next month and am un-decided on what I want to do. The new tank
36" x 40" x 30" high.

What I was thinking is getting 4 or 5 of every 20w led with optics. (Royal blue, 20k, 16k 14k, 10k 6.5k), I was trying to find drivers to put each led on its own to allow multiple programs and flexibility. I reached out to a china company to see if they had what I am looking for and they gave me a quote of ~$700 for 25 drivers(the drivers need to be dimmable via pwm).

Then I was wondering if i should just do a few 50w's and forget about the flexibility of the 20w's. I am worried that the 20w's will not be enough to get through 30" of water. Would 4 50w's with optics be enough to cover 36x40 to start? If everyone thinks the 20's would work then I just need to see if I can find the drivers a little cheaper.

Let me know what you think.. Opinions welcome and wanted.
Mike

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.

 

[A Reef Scene]

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

 

[maglofster]

What is the K rating on your chips, and what driver are you using? Great looking tank by the way.

Two of these:
http://www.ebay.com/itm/EPISTAR-100...078?pt=LH_DefaultDomain_0&hash=item3370376aae

One of these:
http://www.ebay.com/itm/30-36V-6A-2...634?pt=LH_DefaultDomain_0&hash=item3f12203a62

 

[garbled]

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.

 

[garbled]

Edit above: I have a Meanwell HLG150-36B, not a 42.

 

[TropTrea]

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.

I will agree that o.8 Amp seems way low for these 100 Watt LED's. If they would be pulling 100 watta at 0.8 Amps you should be seeing about 125 Volts DC across your LED's. I would not want to run my LED's at that high of a DC voltage for saftey reasons. The usual spec on the LED arrays show they are usualy using 100 3 Watt LED's but only driving them at 1 Watt each for less therom issues. On an array like this it is common to drive them at about 3 Amps and 33 Volts. If your only getting 0.8Amps I can guarantee you that your doing something wrong with your measurement or you only getting a fraction of the light out of your Array than you should be.

1. Put on a pair of sun glasses and set your light to the minimum you can see a glow from the LED's at. Now look at the LED's and see that all the LED's in the array are lighting up. If not you have a defective array. The wiring between LED's in these arrays are thinner than cat hairs and it does not take much of a spike in power to burn these out like a fuse. If one of these wires are opende up it will turn off several LED's in the Array and put the rest of the circuit way out of balance.

2. Get a 10 ohm resistor and use it to replace the LED's. Measure your current and voltage as you slowly increase the power on the drivers. If you cannot get more than 30 volts out of the drive then the driver is either defective or the voltage limit on the driver needs to increased. (this is an internal adjkustment on Meanwell Drivers see your data sheet)

3. Your notye about them running at roughly 32C makes me agree that you are not running them even close to full power. That is only about a 7 C temperature rise and unless you have a fantastic heat sinking system I see more than that running my 3 Watt LED's with 16 square inches of cooling area per LED.

 

[maglofster]

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 about the current. I run mine at about 3A. To me it sound like it could be some problem with the dimming maybe?