Adding Blue LED stars to my MetalHalide hood

[mongor]

it just seems to me that I have read a few times how LED is safer around fishtanks because of them being 12v. (are they using stepup drivers?)

 

Also I was hoping to run my entire array off of a 12v deepcycle battery that I charge with my solar panel. Would be kinda cool to have my DIY solar panel running my DIY LED reef lights. I would go from using the cost of 700w per hour to the cost of 0w per hour if I can pull this off.

 

Any suggestions to make this happen?

[jedimasterben]

You'd be limited by the solar panel's abilities - unless you have spent a large amount of money on the array, there is little chance that it could support the necessary ~100-120w of LEDs that it would take to replicated the metal halide's intensity. (actually, don't you have two halides? Double what I just said)

 

In addition, with 12v input, the LED drivers that you would use more than likely would only have 9-10v output at the most, and would only be able to run 2-3x 'typical' LEDs each, necessitating many more drivers.

[evilc66]

Unless you use a boost driver. But those are not as common as buck drivers, and will invariably cost a considerable amount more.

[farkwar]

it just seems to me that I have read a few times how LED is safer around fishtanks because of them being 12v. (are they using stepup drivers?)

 

Also I was hoping to run my entire array off of a 12v deepcycle battery that I charge with my solar panel. Would be kinda cool to have my DIY solar panel running my DIY LED reef lights. I would go from using the cost of 700w per hour to the cost of 0w per hour if I can pull this off.

 

Any suggestions to make this happen?

 

Get more than one battery.

 

Unloaded voltage is 14+.

 

And while it is only 12v, it has a lot of amps behind it.

 

Some sort of regulator after the battery and before the drivers sounds sound.

 

Grounding it seems problematic maybe?

[mongor]

So the solar panel I am on track with because its actually 6'x3' panel that generates 210w, so that should buy me at least 1.5amps per day.

 

Farwar: that's why i was thinking of some sort of stepup but I think they are rather inefficient. I have a 10amp inverter to 110v, that is also inefficient, but I can run any size power supply that runs off of 110v then.

 

I appreciate you all humoring my desire to try this as unlikely as it might be.

[evilc66]

Running a large array on solar/battery is a tough challenge considering you are looking to add as much efficiency as possible. It's really the drivers that make life complicated, depending on how many LEDs you run per string. Converting DC to AC, to only have it converted back to DC at the driver doesn't make sense. If they are large strings, then boost converters are the obvious choice (total LED vf will always be greater than the incoming voltage from the batteries). Small strings, like 2-3 LEDs becomes more complicated because while you may be able to run a buck driver while the battery is fully charged, the driver will drop out as the voltage at the battery drops from use. At that point you want a buck/boost (or SEPIC) based driver (where the driver can change topology based on the incoming and outgoing needs), and they are fairly uncommon in the commercial world. There are plenty of chips and designs for them, but that's not exactly easy for the average hobbyist.

[mongor]

The array I wanted to run is only going to be 48 3w LED's for a total of 144w. My panel can produce 1500w on a average day and up to 2100w on a good day. If I ran the LED's for 14 hours a day that's 2016w. If I use two 100 amphour deep cycle batteries in parallel, it should never drop below the voltage. But since the lights are running during the day and the panel is charging during the day, it shouldn't really need the battery that much anyway, and I can manually charge it at night if emergencies occur. My solar charge controller cuts off at 11.8 volts anyway so worst case is the light will just shut off. (gets cloudy in the ocean sometime too eh)

 

But the reason I am asking here and not on a solar panel forum is that I need to be able to run the 48 LED's on 12v because of the battery limitations. I mean I could run the batteries in series and get it to 24v but I really don't want to use more than 2 batteries.

 

Are parallel LED' strings really out of the question? I understand they have risks of burning out LED's but how much of a risk is it and will it ruin the whole LED light or just a few cells? It seems like the only option if I want to stay in a reasonable price range for the boost converter at less than 50v.

 

Are the DC-DC boost converters stable enough to run on a daily basis and not affect the light any more than running the LED's in parallel? And when you say boost converter, is that just a Step-Up voltage converter? Like this one?

[jedimasterben]

If you're replacing two 250w metal halides and don't want to sacrifice spread, even the most efficient 48 LEDs will be a stretch IMHO.

 

Evil is talking about a buck/boost constant current driver.

[mongor]

I think the two 250w MH were a bit too much to begin with, just got the fixture for a good price so I used it. Its only a 70g display tank with only zoo's and mushrooms. I have a 50gal refugium on it also, that just has 3x24w pigtales running at 2700k.

[evilc66]

I agree with Jedi. Even 144W of LEDs is going to be a little on the light side for a tank that size. Not by much though.

 

As for drivers, seeing as you have a hard limit at 11.8v, then you should be able to use the Meanwell LDH-45A series boost drivers (available from Mouser). You can get them in 350mA, 500mA 700mA and 1050mA versions. Just make sure that the total vf of any LED string is above 12v. The upper range differs with the drive current, but the 1050mA version goes up to 43v.

 

Any string that is less than 3 LEDs should be using a buck driver. I would avoid making any strings that hover around 12v. That means buck drivers should have no more than 3 LEDs, and boost drivers should have 5 LEDs or more.

[jedimasterben]

I think the two 250w MH were a bit too much to begin with, just got the fixture for a good price so I used it. Its only a 70g display tank with only zoo's and mushrooms. I have a 50gal refugium on it also, that just has 3x24w pigtales running at 2700k.

If you're planning on keeping it at softies, then the 144w might work ok.

[mongor]

Wow, does this mean I am actually getting the ok to do parallel/series mix? I was starting to think it was forbidden.

I am going with a mostly blue layout because the 50/50 reefbright bar I have gives enough white for my tastes. I like a mostly bluish tank and I think the corals prefer it also.

So was going to do 15x445nm (royal), 3x422nm (UV), 3x465nm (Light Blue), and 3x 630nm (red) on each light fixture

3 parallel strings of 8 LED's in series each for a total forward voltage of 23.6v per series @ 700ma

thoughts/comments

Maybe even since I am staying less than 24v total, I can run two batteries in series to get 24v and just use a LED driver instead of a boost?

[jedimasterben]

Buy more drivers.

[evilc66]

No. You should run LEDs in series on each driver. You can run the drivers in parallel on the batteries though. Nothing wrong with that. Run the batteries in parallel for greater capacity and just use the Meanwell LDH-45A drivers for each color. Decide now on what you want the max current to be, as that will determine how many LEDs you can run per driver (in series).

 

Where are the whites in your LED setup? Running heavy blue is one thing, but you still need whites as a base. 630nm red is pointless really if you want more red over what the whites would give you. You would be better off with warmer whites, or adding 660nm deep red if you really want some benefit from adding them. Really though, I'd avoid them unless you see a need for them.

[mongor]

I already have a reefbright 50/50 Led light on the tank that provides enough white. I will swap the 630 for 660's and decrease to only 3 leds on the whole setup.

 

I understand about running multiple drivers in parallel, not the led's that makes sense.

[evilc66]

I thought the intent for the full retro was to make a complete cohesive system. The Reefbrite strip would stick out like a sore thumb next to the rest of it. Plus, you will want to cluster the LEDs to make everything blend together better. Having the whites basically isolated away from everything else will create color shadows.

[mongor]

Sorry, been gone for a few weeks. But the good news is that I have gotten most of the LED's and the Meanwell drivers recommended here and have already (successfully) built one of the 3 strips I am doing. The info here has been soo helpful and the lights make the tank look GREAT! LOVE IT!!!

 

I ended up going with the mix of LED's that Jedi had recommended earlier. After getting bashed here a bit, I rethought the whole process and decided to do it right. So the whites will be mixed in with the blues and violets.

 

Evil, I will probably end up selling the reefbright strip (it was just temporary anyway) I can probably get what I paid for it because of the cheep price I got it for, so it served its purpose.

 

I found an old plastic hood for my 75g bowfront (forgot I even had it) that will hide the LED strips nicely. I put it away because it couldn't take the heat of the MH's. I put a fan going in and out of the two sides and it keeps the LED strips pretty cool.

 

I went a bit cheep on the heat sinks though. I had an old aluminum sliding door we took out a few months ago, and cut the sides to my length and affixed the LED's to one side of them. The exterior part of the door is flat, so perfect for mounting the LED's and the interior part of the door has aluminum tracks that serve nicely as fins to disperse heat. With the fans running over them, the are only a bit warm. I was told that as long as they are not hot, that temperature is ok, yes?

 

I am going to make three 48" strips each 4" wide with 2 rows of 12 LED's so thats 24 LED's per strip or 72 LED's total. Times 3w each is 216w total power. I have read that it is roughly 1w LED to 2.5w MH so if that is true I should have about 540w equivalent. Does this all sound true?

 

Also, how does everyone feel about thermal paste to attach the LED's? (seems quick and easy vs using screws)

 

And one last question, can anyone recommend a timer/multistrip that has mutiple on/off timers. Having a total of 7 meanwell drivers, I was thinking that if I setup each driver onto a separate timer that I can create a morning/noon/evening/night effect by turning on more and more of the strips as the day went on. but 7 timers is alot to fit into a small space.

 

Again, thanks for all the help I was so afraid of LED's, but now I am loving them.

 

Gary

 

p.s. dropped the whole solar panel powering the LED's strips. Too many projects at once was making my head spin