# Need LED lighting help



## Dworon1 (May 19, 2012)

I'm really hoping that someone has enough knowledge to just recommend a DIY setup. I can solder and do all the work I just really need to know what to choose for the setups. 

I've searched through various forums and my head is spinning. 

I have 4 different sized setups to light:
- 24x18x24
- 12x12x18
- 18x18x24
- 18x24x12
Substrates will reduce the height by 6 inches or so and I would prefer to have the fixture nearly resting on the top glass or as close as possible. 

I know about the pre-made fixtures available but really think DIY is better for my needs - I could be wrong. 

I'm not rich but would like to do this right the first time and am willing to spend if I have to. Would rather not have to get crazy with separate dimmers for different temperatures in a fixture if I can avoid it.

Anyway, these are my demands. 

I know I'm asking a lot an appreciate any help from those with experience. I have been thinking Cree XML for their efficiency but am open to suggestions. 


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## Toxic (Jul 9, 2012)

A cheap method would be to get LED Light strips from ebay.
This is the link where i got mine...
5050 Cool White 5M 300Leds IP65 Waterproof 6500K SMD LED Strip Light Hot Sell | eBay

I got the power supply here:
Ledwholesalers 30 Watt LED Power Suppply Driver Transformer 120 to 12 Volt DC Output, 3207 - Amazon.com 


When they arrived, i cut them and soldered them together. 










When i finished, i had some LEDs left over so i put it on the door of the terrarium. This is how it looks finished. 










I only used cool white LED's, but you can add some warm white which would make it look nicer. Overall, it all cost me about $30 and it looks great.
I hope this helped


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## Dworon1 (May 19, 2012)

That's cool an I appreciate your feedback but from what I read I might not get enough par and lumens. I'm thinking something more along the lines of a few high power, high efficiency bulbs soldered into a heat sink.


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## TerraFerma (Feb 20, 2011)

Dworon1 said:


> That's cool an I appreciate your feedback but from what I read I might not get enough par and lumens. I'm thinking something more along the lines of a few high power, high efficiency bulbs soldered into a heat sink.


What kind of plants are you looking to keep and do you care how fast they grow? On my 24" x 18" x 24" I run 16 Cree XM-L's with a mix of cool white and neutral white + 5 tri-stars (three LEDs on one sink) w/ Philips Deep Red, Cyan and Royal Blue. Its probably too much and a waste of money but I wanted the ability to have tons of lumens, but adjust it so as not to burn plants (XM-L's on a potentiometer dimmer, which is a very cheap way to dim), and wanted to get nice output in the useful wavelengths that the white LED's don't put out heavy amounts of (the tristars; the roughly RGB combo close together put out a kind of white light...but not really). 

Its only been a few weeks so I can't report amazing results but it should work OK. The tristar's I run for dawn and dusk and it is a pleasant colored light for those purposes. I could probably just run 8 of the white XM-L's and it would be more than adequate. But half the fun of DIY LED's IMO is getting to put a bunch of crazy stuff on there that is to your liking.


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## Dworon1 (May 19, 2012)

I have some bromeliads and I'd like to get some moss going on fern panels. I don't care so much about growth as long as they stay healthy and the broms keep their color.


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## TerraFerma (Feb 20, 2011)

Sorry I added to my first post after you replied. The thing I pictured could do well as a light bar on an off road truck when run at full blast. If you just want to keep stuff going nicely/alive you could just run 4-8 XM-Ls depending on the tanksize. That is probably still overkill. Plenty of folks run lower output Philips and Taiwan made white led's and do just fine; you will just need more of them vs. the XM-L's. The manufacturer websites all have the output at various mA driving levels so you can work out how many lumens you want and what LED's are needed to provide that.


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## Toxic (Jul 9, 2012)

Dworon1 said:


> That's cool an I appreciate your feedback but from what I read I might not get enough par and lumens. I'm thinking something more along the lines of a few high power, high efficiency bulbs soldered into a heat sink.


Ohh ok sure. It was just a cheap alternative for using LEDs. I use to have cfls but it was mostly burning my plants. When i switched to these LEDs, i noticed a lot new growth.


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## NathanB (Jan 21, 2008)

For X-mls I've found 1 every 6" works well. You don't need a lot. If you have want a good spectrum you can add a deep red for every 2-3 xmls. It's not necessary though.


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## skanderson (Aug 25, 2011)

i am using diy cree xmls over 4 vivs now. i like a 2 warm to 1 cool ratio but you may like a different color balance. over my 12x10x18 and 12x10x 24 vivs i am using 1 or 2 cree xml u2 as the cool white and 2 or 1 cree xml t5 for the warm led for a total or 3 leds over each viv. i am not using optics on the leds as that gave too much spotlighting. the par numbers at the floor are about 40 which gives me a good light gradient for different plants in the viv. i am growing orchids in all of these vivs and they seem to be doing well in them. my rule of thumb is around 3 xmls per square foot of viv floor seems to give decent lighting. on the small vivs the xmls are currently only being driven at 1amp ea so i could really ramp it up to increase lighting if i want. it might be worth using somewhat cheaper and quite a bit less expensive leds like rebels and increasing the number of emitters. this would make it easier to get a good color blend if you are mixing emitter colors. when i get my new 18 cree xml debugged over my 36x18x36 inch viv i will post pics. hope this helped. one other thought if you want to use higher power very efficient leds is that luxeon has come out with the rebel m. it has a warming color to it i have read but it is slightly more efficient than xmls and can be powered at 11 watts at one amp so it is easier to get drivers. steves leds is supposed to be getting these in stock but ive been waiting for them for more than month now so i dont really know. i was told they were being help up by the chinese new year.?


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## TerraFerma (Feb 20, 2011)

skanderson said:


> i am using diy cree xmls over 4 vivs now. i like a 2 warm to 1 cool ratio but you may like a different color balance. over my 12x10x18 and 12x10x 24 vivs i am using 1 or 2 cree xml u2 as the cool white and 2 or 1 cree xml t5 for the warm led for a total or 3 leds over each viv. i am not using optics on the leds as that gave too much spotlighting. the par numbers at the floor are about 40 which gives me a good light gradient for different plants in the viv. i am growing orchids in all of these vivs and they seem to be doing well in them. my rule of thumb is around 3 xmls per square foot of viv floor seems to give decent lighting. on the small vivs the xmls are currently only being driven at 1amp ea so i could really ramp it up to increase lighting if i want. it might be worth using somewhat cheaper and quite a bit less expensive leds like rebels and increasing the number of emitters. this would make it easier to get a good color blend if you are mixing emitter colors. when i get my new 18 cree xml debugged over my 36x18x36 inch viv i will post pics. hope this helped. one other thought if you want to use higher power very efficient leds is that luxeon has come out with the rebel m. it has a warming color to it i have read but it is slightly more efficient than xmls and can be powered at 11 watts at one amp so it is easier to get drivers. steves leds is supposed to be getting these in stock but ive been waiting for them for more than month now so i dont really know. i was told they were being help up by the chinese new year.?


The M's look very cool. Yes there were 10 non working days in Feb this year due to Chinese New Year so that has slowed production of a lot of electronics stuff. Do you know what pricing on the M's is going to look like?


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## RabidWombat (Aug 4, 2012)

XMLs are nice, but they're expensive and you're probably not going to want to run them at full power (3000ma, 10w, 1000 lumens each). That's blinding.

I have XMLs running on my two tanks currently. I also have a small plant grow-out tank that I've got another set on. They were about $7.50-$8 per led. Running at about 750ma is plenty of light. 

I'm still waiting to get the shipment in, but I found some cheap LEDs that I'm really looking forward to trying. They're from Epistar. They get good reviews online. The LEDs are max of 180-200 lumens. You'll end up using a few more, but they're reaaallyy cheap. Less than $0.50 per LED.

The downsides are that you've got to do a little extra soldering and you're ordering straight from China. It can take a few weeks to get them. My first shipment came in 2.5 weeks.. still waiting on the second one.

LEDs - High Power Epistar Chip 3W LED Bulb Diodes Lamp Beads 180lm 200lm, Cold / Warm White, for 3W 6W 9W 12W LED Spot Light 20pcs/lot-in Diodes from Electronic Components & Supplies on Aliexpress.com

PCB board - 1W / 3W LED PCB/ Aluminum base plate/ Circuit board/ PCB LED board for led high power lamp, 100pcs/lot & free shipping-in Connectors from Electrical Equipment & Supplies on Aliexpress.com



You can also find really cheap drivers on Aliexpress ($5-$8 per driver). You may end up buying a few at a time.

Best China Electronics Products Online Shopping Store - Free Shipping & High Quality has some good prices too. They're a little more expensive than Aliexpress but you can buy most stuff in singles.


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## Dworon1 (May 19, 2012)

I found XMLs for 6.50 each which isn't too bad considering I'll need less of them. Those cheaper LEDs look ok but I'm concerned with longevity. The site says "high power LED 1000 hours". I may use Ali for drivers though. 


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## senditdonkey (Jan 19, 2013)

I have a few of these kits. Very, very happy with LEDs and distributor.

Aquarium DIY Dimmable LED Kits with optics


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## jthayer245 (Jan 6, 2013)

I too am looking for LED solution, I have frogs and live plants and want to find a bulb replacement (LED) that promotes growth and increases plant growth.


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## Dworon1 (May 19, 2012)

Senditdonkey - Thanks for the info. How many of these do you need per sq ft? Is there any downside to these besides having to use more? I've just heard such great things about Cree and I'm not sure if the things that make Cree "high quality" are going to make a practical difference in my vivs. 


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## senditdonkey (Jan 19, 2013)

Dworon1 said:


> Senditdonkey - Thanks for the info. How many of these do you need per sq ft? Is there any downside to these besides having to use more? I've just heard such great things about Cree and I'm not sure if the things that make Cree "high quality" are going to make a practical difference in my vivs.
> 
> 
> Sent from my iPhone using Tapatalk


I have them on a 4" wide heat sink and put in rows of 2 about every 4" to cover a large space.WHen I put more LEDs the heat sink got hotter then I liked. I don't see the need for more LEDs, they are very bright. have them on up to 6' heat sinks which I have 38 LEDs. On the individual tanks I have 6 LEDs for 12x12x18's and 8 LEDs for 18x18x24's with a mix of 4500 and 6500 LEDs. On 200 gallon freshwater aquarium I put 38 LEDs with a mix of 4500, 6500, 10,000 and blues. They run from room temperature to warm, none get hot. I don't know the math or specific plant requirements, but I'm happy and my broms are getting better color. Visually they put off way more light then my T5's. There is a guy that made a website with a build thread around here somewhere, it helped make my decisions easier.


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## easternversant (Sep 4, 2012)

senditdonkey said:


> There is a guy that made a website with a build thread around here somewhere, it helped make my decisions easier.


I think this is the build thread you mean. Are you happy with the results? Because I'm thinking of following Chuck's build as well.


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## nonliteral (Mar 26, 2012)

Dworon1 said:


> I found XMLs for 6.50 each which isn't too bad considering I'll need less of them. Those cheaper LEDs look ok but I'm concerned with longevity. The site says "high power LED 1000 hours". I may use Ali for drivers though.


One thing you may want to consider with the "more of these" / "less of those" decision is that at one extreme, you have a handful of high-output LEDs spread a ways apart, giving you very directional lighting with sharp contrasts -- a lot of bright spots and shadows, depending on what your plant growth is like and where it is in relationship to the LED. At the other extreme, you have a larger number of lower-output LEDs spaced closer together, giving you more even, less directional lighting without as much dramatic contrast, and with possibly less extreme shading as your plants grow in. 

Neither way is really "better" -- it just depends on what you like, what kind of plants you want to grow, and what effect you want to achieve. 

In terms of cost / effort, there's really very little difference -- you might spend an extra 20 minutes during your build soldering more low-power LEDs, and low power LEDs are probably going to be slightly less efficient (in this class of LEDs, not likely enough to make much difference in heat or operational cost, though), but the tradeoff is going to be a more even spread of lighting.


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## Dworon1 (May 19, 2012)

Wow. Thanks everyone for the info. I'm going to go with one of the kits. Thanks again.


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## skanderson (Aug 25, 2011)

dont know what the pricing on the rebel m will be like. if i was doing it over i would not use xmls on anything under 24 inches deep because of the shadowing i get with the sparse emitter placement. i have read that the epistar leds are not going to be binned for reliable color and output but i have never bought any and dont really know. i am using a diy driver dimmer combo that i bought from a guy on the planted tank forum. it was 80 bucks i think and let me run 4 strings of 12 leds at 1 amp max and have complete dimming and on off timing of the strings. good luck with the kit. post pics and show us how they look. the more working lights we all see the easier it will be to design a good diy light for a viv.


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## senditdonkey (Jan 19, 2013)

easternversant said:


> I think this is the build thread you mean. Are you happy with the results? Because I'm thinking of following Chuck's build as well.



Very happy. Am in the process of finishing the room. You can mix and match the LEDs beyond what order form says. Just put a note in memo part of order form. I see parts of the tanks that were black holes before. I got the jungle dawn LEDs for my tanks that are not on a rack and am happy with those as well. It just made the whole light system simpler and more condensed. I messed with led spacing a bit and now only have 1 computer fan per shelf for cooling. Ordered on Sunday and got heatsinks, LEDs, thermal adhesive on Friday. I would order thermal adhesive as chuck suggested, I like better then what came in kit.


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## Dworon1 (May 19, 2012)

Ok so I decided to go with a kit from aquastyle online - 120 LEDs with the choice of either
2 drivers that can power 5 strings of 12 LEDs each or
5 drivers that can power 2 strings of 12 LEDs each

The thing is my room is basically split in half and there will be 52 LEDs on one side and 68 on the other. The LED strips I plan on making for each side are (by number of LEDs connected together on each strip)
19, 15, 6 and 12 on one side (total of 52) and
16, 12, 6, 19 and 15 on the other (total of 68). 

I would like to use just 2 drivers if possible so - is the recommendation a rule or suggestion? Could I get away with 68 split as laid out above on the driver? If so I might want to add a few more LEDs and increase the number on the strips a little. 
In other words, does 5 strings of 12 (60) mean 60 in any configuration or is there something significant about how you split them up? And can you put more than the suggested number of LEDs on a driver safely? 

If you have any suggestions of a better way for me to do this I'm all ears. 

Thanks all!


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## Dworon1 (May 19, 2012)

Could I get away with 18 gauge wire or should I use something thicker? Thanks.


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## Dworon1 (May 19, 2012)

Just wanted to run this by you guys in case someone has input. I'm powering fixtures with 6, 16 and 20 LEDs. The power source is supposed to power 5 runs of 12. So I'm going to under power the 16 fixture and use potentiometers to adjust down the power level to the 6 and 10s (the 20 will have to be divided in half). Make sense to anyone? I'm new to this but this seems like the best solution after conversations with a lighting store and radio shack. Pic is of the 16s and 20s.


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## DrawntoLife (Nov 12, 2009)

As per your wire gauge question, I run 18 XMLs and between it and the drivers there is 6.5' of 22awg stranded wire. Just to give you an option.  also mine to through d sub connections. So yes you can use smaller


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## nonliteral (Mar 26, 2012)

DrawntoLife said:


> As per your wire gauge question, I run 18 XMLs and between it and the drivers there is 6.5' of 22awg stranded wire. Just to give you an option.  also mine to through d sub connections. So yes you can use smaller


Yup. I tend to wire my drivers to the fixtures with old cat 3 ethernet cables (I've got a ton of them, and I can cut them in half, wire one side to the fixture, the other to the driver, and use an RJ45 coupler as a quick disconnect), and the conductors are easily 24 gauge, if not smaller.


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## Dworon1 (May 19, 2012)

Wow. I'm in over my head. Whenever I think I learned something I find out I was wrong. This project is a lot tougher than I thought it would be. Next time I'll just save up and get pre-made fixtures. 

Anyway - sorry to keep bothering you guys. I think I'm close but don't want to risk frying my LEDs or drivers. 

Apparently the dimmer for the Meanwell 150 42b does not need a 10v power source like some of their smaller drivers do. Learned that after waiting a week for 10v power sources to get here. 

The site I bought the kit from recommends setting up 5 strings of 12 LEDs on each driver. I needed slightly more LEDs so I bought an extra driver (without really knowing what I was doing) and plan on running strings of 12 but only 3 or 4 strings on each driver. I rewired so that I can have exactly 12 in each string but will not have the full 5. I don't fully understand what effect this will have but as of this moment think it will work - subject to change. 

I'm finding that this is all pretty complicated. The site I bought them from doesn't give any tips on installing and doesn't return my emails. I've been searching online and most of the information is way over my head. Some of the "layman terms" info I've found is helpful but doesn't apply specifically to the drivers I'm running. Long story short - I don't know the effect of running less strings and am having a hard time finding answers I'm comfortable with. 

On top of that I'm not sure how to test if the potentiometer (dimmer) is working. I connected everything and played with the dimmer while testing the output with a multimeter but didn't see any effect of turning the dial. I tried all of the different things the multimeter tests (dc volts, ohms, etc) and didn't see any change. Also - do I have to open up the driver to tweak the output with the little dial inside it or will the dimmer take care of that? And should I put fuses into the lines? I'm assuming at this point that I should. Assuming.

Like I said I feel like I'm close to getting this together. It's very frustrating because it is holding up the rest of my work. I want to get the lighting set and then I can plant the tanks and set up the misting system. My collection of plants that I figured would have been in beautifully LED lit tanks by now are dying slow deaths on my windowsill. 

So yeah - It's right there. I can solder confidently and have the multimeter and all the parts needed to make it work I'm just afraid that if I wire it up I will fry everything. 

Sorry for the long rant but if anyone can see through this fog and make a recommendation I would greatly appreciate it. 


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## Dworon1 (May 19, 2012)

Some pics. The connections, fuse and pot. I'm not getting any light. Thoughts? Anyone?!


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## easternversant (Sep 4, 2012)

Have you opened up your drivers to check? I believe that there is a small knob that can be turned with a screwdriver. And have you tested each connection? 

I have the materials for an LED build coming in (hopefully this weekend!) and you are not giving me any confidence!


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## Dworon1 (May 19, 2012)

I'm not sure my driver is that kind of driver. It doesn't easily come apart. Anyway I assume (yeah I know) that from the factory they would have it turned up. 
I work a lot and don't have the patience for this. Thought that it would be plug and play but it's not - at least for me. Hopefully you have better luck. 

In related news - if anyone knows anyone that has experience with this kind of thing that could use extra cash and can travel to lower manhattan please let me know.


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## easternversant (Sep 4, 2012)

What driver do you have? I didn't find that in an admittedly quick perusal.


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## Dworon1 (May 19, 2012)

Got it from aqua style online as part of a kit. Dedicated dimmer line and supposedly should power 5 lines of 12 LEDs each.


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## nonliteral (Mar 26, 2012)

I wish I had some practical advice, but I've never tried wiring one in parallel. One place you might go to get answers would be the lighting forum on nano-reef.com -- if a quick search there doesn't come up with what you want to know, post a question -- they're usually very friendly and helpful over there (even if you're not lighting corals). 

There's a lot of LED talk on reefcentral also, but I've always found the lighting crowd on nano-reef to be a bit more friendly.


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## Dworon1 (May 19, 2012)

I'll try that. Thanks. I did some searching generally with google which linked me to them but I didn't find anything exactly on point. Thanks again.


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## usctom (Mar 30, 2013)

Have you tested every led?Accessories - LED Testers - Rapid LED 
When you plug it in or unplug do any of the lights flicker? I have never run lights parallel but have wired up a couple for reef tanks. Maybe trying wiring each one at time with driver. Nano-reefs is a great resource. They have a a lot of people that have used those kits.


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## Dworon1 (May 19, 2012)

Nothing happens when I plug it in. I tried testing the LEDs with one of those battery powered testers and they light. It might be the fuse which wasn't part of the kit and sold to me by a guy who didn't seem 100% sure about it. I'm afraid to power it up without the fuse and fry it though. 
Seriously if you guys know a reef tank guy in my area who is good at this I'll pay him. I don't want to destroy this stuff trying to figure it out.


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## rabu92 (Mar 9, 2013)

Hi, this thread is a good read for building a parallel string setup. It describes all the tests you would need to do, how to wire things...

especially look at Kcress' comments, he seems to know all the electrical stuff


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## NathanB (Jan 21, 2008)

I ordered all mine stuff through a US company, and they provided all the instructions and support. I used the other drivers so I can't help much. You can try posting on one of the reef/planted tank forums. I'm sure someone will help you figure it out.


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## Dworon1 (May 19, 2012)

Next time I'll use a US company. Aqualstyle got good reviews for the products but they have no support. I posted on the reef forum and am waiting to hear.


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## rabu92 (Mar 9, 2013)

Hi, I think I can help you out... or at least I'll try 

*The basics:*

*Voltage, Amperage and Wattage:*
Watt = Volt*Amp

*The LED's:*
Each LED has 2 main characteristics you need to know, Forward Voltage (Vf) and Amperage (usually mA which is milliAmps). You can find these on the data sheets of the LED's you bought. If you multiply the Vf and Amp you get the wattage. 
_With your Bridgelux 3W LED's:
Vf = 3,7
mA = 700
Multiply those for the wattage: 3,7*0,7 = 2,6W._​I'll be using those numbers for the rest of the calculations/explanation.

*The Strings:
Series:*
You have a string of 12 LED's which are wired in Series:
In series the voltage needed for a string of LED's is the sum of the Vf of each LED in the string. 
_So 12 LED's of 3,7V give you 44,4V._​The amperage needed for a string of LED's in series is the same as used by 1 LED in the String.
_So that would be 700mA._​*Parallel:*
Those strings will be wired in parallel to the driver:
For explanatory purposes imagine that one string of 12 LED's is one big light of 44,4V and 700mA.
When wiring the strings (big light) in parallel the voltage needed to power the strings is the same as used by one string.
_So that would be 44,4V._​The amperage needed to power the strings is the sum of the amperage used by each string.
_So when wiring 5 strings in parallel that would be 3500mA or 3,5Amps._​
*The Driver:*
Drivers used with LED's are constant current drivers. This means they provide a constant amperage and a variable voltage. The needed voltage is automatically adjusted by the driver. 
So when selecting a driver you need to look for 2 things:
1) The max voltage of the driver is higher than that needed from your LED setup. (Very important because: too low will kill your driver)
2) Get a driver that provides the same or lower Amps needed from your setup.(Very important because: too much Amps will kill you LED's, too little isn't bad but you won't get full power from you're LED's)
_So when you want to provide power to 5 parallel strings of 12 LED's each, you will need a driver that can produce 3,5Amps and provides at least 44,4V.
The driver you have is a 150W 48V driver. Which means it provides 3,125Amps. (Remember the Watt=Volt*Amps rule?). This means it will be able to power the LED's to about 90% of full power._​
Now that I've written this and quite some time has passed, I hope you'll be able to understand the explanations on the thread I linked a few posts back. You should really read it if you want to fully understand what you're supposed to do.

BEFORE POWERING A NEW SETUP, ALWAYS...REPEAT...ALWAYS DO A CONTINUITY CHECK AND SHORTED WIRE TEST
these are explained in the same thread I posted, it's on page 3, last post by kcress. If you don't do these, you can kill your LED's, Driver or even worse cause a fire.

*To answer some questions you had:*
- Yes you can drive 6 LED strings and 12 LED strings on the same driver but that requires a lot more fine tuning than simply doing strings of equal amounts.
- When your driver doesn't seem to power the LED's try replacing the Pot by an AA battery (1,5V). If that doesn't make the LED's shine than something is wrong with the driver or you have a short (dangerous), or one of your fuses have blown.
- If you want to power 3 string of 12 LED's with the 150W driver, you can but it has a risk. You'll be able to send the full 3,125Amps from the driver through 3 strings. Which means more than 1Amp for each string. Which is more than the max of 0,7Amps. Which means you'll kill the LED's. You can however dim the driver so the output is 2,1Amps, which will give you 0,7Amps for each of the 3 strings.

Anyway I hope this has helped 
and again, read the thread I linked


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## Dworon1 (May 19, 2012)

I'm at work and only got to quickly skim the reply but wow. Thanks for the detailed explanation. And I'll check out that thread later.


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## Dworon1 (May 19, 2012)

So I shouldn't power up only one strip of 12 with the driver and when I power up the 3 in parallel I should have the pot turned all the way down. Is there a way to test if the pot is working?
Also, just to be sure, is this how I would hook up the pos and neg from the driver to the strips?







And the fuse would go like this?








What would I have to do to use smaller strips (like 10 or 6 LEDs)? If its too much trouble I can just run wires between fixtures to make an even 12 per parallel connection. 

Thanks again to everyone for the replies. I can't tell you how much I appreciate it.


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## rabu92 (Mar 9, 2013)

> So I shouldn't power up only one strip of 12 with the driver...


You could by dimming it all the way down to 0,7Amps, but it would be a waste of driver power. One string uses only 31Watts while the driver can deliver 150Watts. Drivers tend to have higher efficiency when they run at full power, thats why it's best to get a driver that closely matches the power needed.



> ...and when I power up the 3 in parallel I should have the pot turned all the way down.


All the way down is bit much  However to avoid destroying your LED's you do have to start by turning the pot all the way down, then plug in the driver. You should then measure the current (amperage) that goes through your string and turn the pot up slowly until the current reaches 0,7Amps. Then somehow mark on the pot not to go past that point.
It's safest though to run the LED's at 90% or so, something like 0,65Amps to avoid burning them out.



> Is there a way to test if the pot is working?


The only way I can think of is connecting it to a wall wart (or maybe a 9V battery), then measuring the voltage that goes through it with a multimeter. If no voltage is detected then your pot is broken.



> Also, just to be sure, is this how I would hook up the pos and neg from the driver to the strips?


You have to do a test on your LED's to see which way is positive and which is negative. Then just connect the positive from the driver to the negative from the first LED.
This is how you find the pos and neg of the LED's: 
- set the multimeter to diode test (there should be a diode sign on the meter) 
- then connect the red probe (pos.) to one site of the LED and the black (neg.) to the other. 
- If it lights up then you know the pad touching the red probe is the LEDs' pos side and the pad touching the black probe is the neg. 
- If it doesn't then reverse the red and black probes and it should light.
All this is shown with pictures here (second to last post).

You should test each LED to see if they are all wired correctly, Neg of one LED to Pos of the next. 
It should look like this: Driver+ wire(with fuse) -LED+ wire -10LED's+ wire -LED+ wire -Driver

As you can tell, I keep referring to that thread  To be honest I haven't done this myself, my DIY cree LED's should arrive next week. All the things I know I have learned from reading threads like that one.



> And the fuse would go like this?


As far as I can tell yes, remember though that each string is a big light. And you want to protect each light from getting too much power. This means that you'll have to add a fuse to each string of LED's. 

I'm not sure this next bit matters but to be safe place the fuse in between the pos of the driver and neg of the first LED. (so on the first wire going from driver to string, not the last one going from string to driver) I hope that made sense 



> What would I have to do to use smaller strips (like 10 or 6 LEDs)? If its too much trouble I can just run wires between fixtures to make an even 12 per parallel connection.


I haven't seen anyone do different amounts in strings. I do however think it's possible and I think I know how but I don't want to be the cause of destroying your LED's  So I would go with running a wire between the strings to make them all 12 each.


And again I'm no electrical engineer, I'm just a guy who read a lot of LED threads  So if anyone spots a mistake don't hesitate to tell me.


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## nonliteral (Mar 26, 2012)

Dworon1 said:


> Is there a way to test if the pot is working?


A potentiometer is just a variable resistor, so set your multimeter to resistance in whatever range is appropriate for the pots rating, and turn it from one stop to the other -- you should see the resistance value on your multimeter roughly matching the pots rating. 




Dworon1 said:


> Also, just to be sure, is this how I would hook up the pos and neg from the driver to the strips?


Each string should be wired from the positive pad on one star to the negative on the next, etc, so once it's complete, the LED at one end should have an open positive pad, and the other end a negative pad -- attach positive off your driver to the open positive end, and negative to negative.

If you're not sure which pad is positive or negative on the stars, then you're going to need to determine that and (probably) rewire the string. The easy way to tell (absent marking on the star) is to take a battery holder with 2 AA cells (most vendors throw one in for free with each order, but if not you can find one very cheap at radio shack), and touch the positive lead to one pad of a single star, the negative another pad on the same star (usually straight across); if the LED doesn't light, reverse them. Once you've verified that the entire string is wired for the correct polarity (negative to positive, etc.), you can use the same battery holder to test each solder joint -- hold one end on the appropriate pad on a star, and the other end to the far end of the wire attached to the opposite pad. If the LED still lights, then the solder joint should be good.


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## Dworon1 (May 19, 2012)

It all seems so easy now.








The fuse was the problem. I don't know why. It's not blown,I put it on the positive side between the driver and the LEDs and from what I understand the polarity doesn't matter. 
Any thoughts? And is it really dangerous to operate them without the fuse? Is there another option? Can anyone recommend a fuse that would work?
As always thanks for taking the time to help me with this.


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## rabu92 (Mar 9, 2013)

> It should look like this: Driver+ wire(with fuse) -LED+ wire -10LED's+ wire -LED+ wire -Driver


I'll have to correct that ugly mistake I made  I accidentally switched + and - of the driver.
It should look like this: Driver- wire -LED+ wire -10LED's+ wire -LED+ wire(with fuse) +Driver




> Is it really dangerous to operate them without the fuse?


The job of the fuse is to protect the LED's from getting too much power. In your case the driver can't produce more power than the LED's can handle (running 5 strings on one driver). So the only way the LED's would get too much power is when one of the strings stop working thus sending all the power to the remaining strings.
When one of the LED's burns out that whole string won't work, the remaining strings will get all the power which will burn out the next LED etc. until all your strings have lost at least one LED. When you have fuses they will burn out before the LED's will thus protecting the LED's.
Replacing 5 fuses will be less time consuming and a whole lot less expensive than replacing 5 or more LED's.

Running without fuses is possible but I strongly advise you don't.


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## Dworon1 (May 19, 2012)

So has anyone successfully used a particular fuse? Or can you make a recommendation? Or is it just likely that I haven't installed them correctly? It seems like you would just push the blade fuse into the holder and wire it into the hot side but who knows - I might be missing something. All I know is that the strings light when I take the fuse assembly out of the line. ???


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## Dworon1 (May 19, 2012)

I spoke to the guy at the shop, tested the fuse to make sure it works, and tried rewiring everything - nada. Without the fuse everything lights. 

It's a 1 amp dc fuse but apparently there is a problem with it that I don't understand.


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## rabu92 (Mar 9, 2013)

The fuse should protect the LED's from getting more than 0,7Amps so the 1Amp fuse you're using is way too high.

extract from another thread:
_So if the driver is rated at 1300 ma I need a fuse with a max current of 700ma since I have two strands? Could I use a lower or higher rates fuse such as 1 amp or 600 ma and lower the current of the drivers safely?_
No. The fuse is a fail-safe. If a single LED on any string blows, the driver will send the entire 1300ma into the remaining string, destroying all the LEDs. If you have 700ma fuses on the strings, if something happens to one LED on any string and the driver sends all current to one string, the fuse will blow before it can reach any of the LEDs, preventing catastrophic failure. *The fuses MUST be 700ma each*, any more and your LEDs will blow before the fuse does, and any less and the fuse may blow because it got just a bit too much current (even though the LEDs can withstand more).​
Your setup requires 5 0,7Amp fast-blow fuses (one on each 12LED string). I can't tell from your setup if you are doing this but make sure you add a fuse to each string.
You can probably ask an electricians shop for 0,7Amp fuses or search the net.

Here are some results from a quick google search:
5pcs 700mA fuses
ebay 700mA fuse


some characteristics of fuses:
Amps = has to be equal to the max amount allowed (700mA for you)
Voltage = has to be higher than the voltage going through the circuit (more than 48V DC for you)
Also be sure to get fast blow fuses (the ones that react/break faster)


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## Dworon1 (May 19, 2012)

Thanks rabu92. Can I use those fuses even though I'm DC?


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## Dworon1 (May 19, 2012)

And is there a particular type of fuse holder I'll need? Would these work?
http://item.mobileweb.ebay.com/viewitem?itemId=230905443409&index=12&nav=SEARCH&nid=01085902476


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## rabu92 (Mar 9, 2013)

That's the kind you should get yes, but you'll just have to make sure they can fit the fuses you're going to buy.

It says they fit 6mmx30mm fuse tubes. The fuse I linked on ebay is 7mmx38mm so they won't fit. The 5 piece pack I linked are 5mmx20mm so they will fit but it won't be snug. 
I don't have experience with fuses and fittings but I would imagine placing the 5mmx20mm in the 6mmx30mm housing will work. 
Anyone else want to weigh in here?

So in the end all you have to do is look at the dimensions and compare


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## Dworon1 (May 19, 2012)

Now time to hook up vent fans, mister and plant. 

Thanks again for your help!


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