Electrical Wiring Question

[shanepike]

I have two DIY fixtures from ReefLEDLights. In each fixture are two blue LEDs specifically for use as moon lights. There are two wires (positive and negative) sticking out of each fixture. When I connect a basic DC adapter to the wires, the lights come on.

Two questions:
1. To wire the two sets of moonlights together so I can run them off a single DC adapter (rather than one adapter for each set of lights), should I wire them in series or parallel?
2. They are way</em> too bright to serve as moonlights -- even two are too bright; four would look like the moon was two feet from the surface of the water. What is the easiest way to dim them? Is it as simple as using, say, a 5V adapter rather than a 12V? Or do I really need to wire something inline that will give me control (a rheostat maybe)?

Thanks!

 

[eric b]

I would wire them positive to negative to positive to negative and so on and after all are wired then plug in the power supply and see how bright they are then. If still too bright I know there are voltage adjusters that people on other forums are using on the Jaebo pumps to limited the max speed so you can try one of those (Check ebay) or you can use some type of rheostat as well to adjust the voltage down. The voltage adjusters that people are using are from 5v up to 18v I think if you need me to find the exact part I can search that thread for it I believe it was on RC.

 

[camellia]

Yes, Pretty sure they should be able to both run off the same DC adapter.
I would ask ReefLEDlights if they sent you the correct LEDs. That's a little odd for moon LEDs to be so bright. If it is the correct led, ask if they have another that may make you happier. There not expensive if available and it would be cheaper and easier then buying a voltage adapter etc.

 

[bycjoe]

You could order a moonlight driver(350 mA) from rapidled. Be careful using the DC adaptor by itself, what amp rating is your DC adaptor and what is the amp/voltage rating on your LEDs? You can also wire a resistor in as well.

 

[shanepike]

AFDANW;881740 wrote: give me the rest fo the day, and i willl try to put together a diagram for you. Im at work so i will have to do this in my slow time (im an electronics technician for the FAA). I have designed many circuits, some being LED, so it should not be that hard for me to figure out. How many total LED's are there, White, blue and so on, and how many do u want as moon lights? Are the moon light LED's also going to serve as daylight? Get me the specifics and i will draw up your circuit. I once designed an LED fixture to have about 300 LEDs, 6 were for moonlighting, that ran inversly of the others, and a T5 fixture that all ran on one DC power supply and one toggle swithc that turned on/off the moon light, and day lights including the T5 and LED's, so i imagine yours will not be as complicated as that.

Ha! I imagine not

It's a simple setup. Each fixture has 47 LEDs attached to a circuit board. They leave 2 blue LEDs wired separately to serve as moonlights. (I can't tell if they're wired series or parallel.) I have two fixtures, so two sets of LEDs and two sets of wires. These four LEDs total will only</em> be used as moons.

I talked to ReefLEDLights, and they said the lights could be powered by "any DC adapter."

Thanks for all the help everybody!

 

[ichthyoid]

Unless ReefLEDlights has some magic power regulator hidden inside I don't know how that would work (using 'any' DC power adapter). For long, anyway. Overdriving an LED is a sure path to early failure.

If you have a multimeter, and know how to use it, determining series/parallel wiring scheme (unseen) is pretty simple. Put it on low ohms (~200 or so) and measure from each wire to all others. If there is a reading for all, they are in series. If only for 1/2, then it's parallel.

I'd be careful. Just my $0.02

 

[ichthyoid]

AFDANW;881791 wrote: I agree that LED's are very voltage sensative, but a magic regulator is not really magic at all. here is one that takes any DC voltage up http://www.newark.com/jsp/search/productdetail.jsp?SKU=57M8068&CMP=KNC-GPLA&mckv=|pcrid|20115733101|plid|">to 15v and makes it 5v for $2.50</a>. there are hundreds of these on the market and more expensive ones can take even higher voltage and make it into the voltage u are looking for. It was mentioned that the LED's are on a circuit board, so i imagine there probably is one of these regulators on the board, if they are saying u can put in any DC voltage. My $0.02.[/QUOTE]

You missed my point, apparently. He said ReefLEDLights told him 'any DC adapter' will do. That's where I disagree. I said the 'magic adapter' part in jest. Voltage regulator yes, I agree could work.

FWIW- I too was trained as an ET...Navy, worked FAA/Navy navaids/communications/radar including GCA (precursor to ALS). We were all together at NAS Pensacola, 'back in the day' ;)

 

[shanepike]

Ha! Alright, I missed an important detail: "Any 12Vdc powersupply works to power the moonlights" (emphasis mine)

 

[ichthyoid]

ShanePike;881815 wrote: Ha! Alright, I missed an important detail: "Any 12Vdc powersupply works to power the moonlights" (emphasis mine)

There we go!

Now I feel much better about this thread

Sorry to be such a nervous Nellie, but any time something like this comes up, and I see/read 'all you gotta do is', or 'one size fits all'... My mind see's smoke!

 

[ichthyoid]

AFDANW;881826 wrote: Thats cool, i was not navy, former Air Force here, but i was part of a joint tasking a few years back were i spent 6 months at a navy base in the middle east working in an ET Shop. I miss those days, life was easy back then.

Life at Pensacola was 60% boredom 30% training and 10% scramble!

When fighters were inbound, often in bad weather and running on fumes, if the radar went out we had to get that thing working ASAP!

It taught me that I was capable of most anything, if I kept a cool head. We became adrenaline junkies

That lesson continues to serve me well, almost 30 years later.

 

[shanepike]

ichthyoid;881834 wrote: Sorry to be such a nervous Nellie, but any time something like this comes up, and I see/read 'all you gotta do is', or 'one size fits all'... My mind see's smoke!

As someone who is nervous about it begin with and, on top of that, tripped a GFCI while using a Dremel with wet hands cutting coral this morning, I appreciate it

And for what it's worth, word from ReefLEDLights is to wire them in parallel. That will send 12V to each of the 4 lights, right? What would be the downside of using a 5V DC adapter instead?

 

[picoreefguy]

yes wireing them parallel will send 12 volts to each led but it will split the amperage between them, where as wireing them in series would split the voltage between them. using a 5 volt adapter may not even be enough to light the leds. i would wire the leds parallel and put a potentiometer in line with the power supply which should allow you to dim the leds.

 

[ichthyoid]

ShanePike;881841 wrote: As someone who is nervous about it begin with and, on top of that, tripped a GFCI while using a Dremel with wet hands cutting coral this morning, I appreciate it

And for what it's worth, word from ReefLEDLights is to wire them in parallel. That will send 12V to each of the 4 lights, right? What would be the downside of using a 5V DC adapter instead?

Yes, in parallel voltage is constant.

As to using a 5 volt adapter, the current would be 2.4x's what it is with 12vdc, for the same power. Too much current will cook them.

FWIW-
LED's are usually run as fixed voltage/variable current devices.

This is why companies like Meanwell (LED drivers) are making a killing

 

[shanepike]

It's slowly beginning to click (Slowly.) It's becoming more and more desirable to just take AFDANW's advice and use a black marker to color the glass covering the LEDs for a ghetto dimming solution

 

[ichthyoid]

ShanePike;881854 wrote: It's slowly beginning to click (Slowly.) It's becoming more and more desirable to just take AFDANW's advice and use a black marker to color the glass covering the LEDs for a ghetto dimming solution

Everything was MUCH simpler, before everyone decided they wanted 'dimmable' LED's

Layers of screen, or raising them also work. Raising may be best, because irradiance varies (closely) with the inverse power of the square.

So,
double the distance ~ 1/4 w/cm^2

Triple the distance ~ 1/9 w/cm^2

Ex:
Just a 25% increase in distance equals about 56% of the original light intensity at the coral.

 

[shanepike]

Regrettably, changing the distance isn't an option, and even the two bootleg options might not work now that I think about it because everything has a spray-on protectant that nothing</em> will stick to.

Can I wire in a pot/rheostat to dim them like Picoreefguy suggested?

 

[ichthyoid]

AFDANW;881887 wrote: I like the screen idea, it is similar to the marker idea, but less bootleg. The distance info i good knowledge that i was unaware of. I may lower my light a bit to get more light for my coral.

I suggest that you do so gradually, if possible. You don't want to shock them with a big increase all at once.

 

[ichthyoid]

Light, or more precisely, 'photons' are a quantitative thing. It's all about the amount per unit of time.

A x B = C

If,

A = photons, and

B = Time, then

C = photon seconds, so

You can use-

twice the photons for half the time, or

half the photons for twice the time,

and

Their both the same number, aren't they?

So changing your total 'photoperiod' or 'on' time, is a way to adjust your light, as well.

 

[bycjoe]

AFDANW;882065 wrote: i know at one point i said you could use pot/ rheostat, but now, thinking about it more, i would say you should avoid that. E x V= P. I think lowering the voltage with a potentiometer would cause an increase in current. resulting in blown LED's. U may want something like http://www.rapidled.com/moonlight-driver-350ma/">this</a>. I could be wrong though. Someone please verify.[/QUOTE]

Yes that would work, now correct me
If I'm wrong, a pot and a resistor wired jn series could accomplish the same thing as well

 

[picoreefguy]

AFDANW;882065 wrote: i know at one point i said you could use pot/ rheostat, but now, thinking about it more, i would say you should avoid that. E x V= P. I think lowering the voltage with a potentiometer would cause an increase in current. resulting in blown LED's. U may want something like http://www.rapidled.com/moonlight-driver-350ma/">this</a>. I could be wrong though. Someone please verify.[/QUOTE]

if you wire the pot in series then you lose current not voltage which is how the dimming is achieved