Electronic noob wants to make underwater LED lights

[crazybry79]

Never mind. found one that will power both lights!

http://www.amazon.com/DROK-Constant-Current-Converter-Regulated/dp/B00E8D7XYG/ref=pd_sxp_grid_pt_1_0

Now THIS I can get into!

 

[Gryd3]

Never mind. found one that will power both lights!

http://www.amazon.com/DROK-Constant-Current-Converter-Regulated/dp/B00E8D7XYG/ref=pd_sxp_grid_pt_1_0

Now THIS I can get into!

This one looks better than the last.
"Constant current range :0.1-12A"

Good find. So you would need to set the 'constant current output' to 900-1000mA, then simply connect your LED's in series. (Make sure you don't use too many LEDs, or the forward voltage will be too high).

You're on the right track!

 

[crazybry79]

I was initially thinking of this guy running both o f my "lights". But how would my current regulation work?

LEDs draw 1000ma each. If theres 5 IN Series, Do I Add the amps? (5000ma?)

 

[Gryd3]

I was initially thinking of this guy running both o f my "lights". But how would my current regulation work?

LEDs draw 1000ma each. If theres 5 IN Series, Do I Add the amps? (5000ma?)

Nope..
When you add things in series, their voltage gets added together.
When you add things in parallel, their current gets added together.

So... if you are putting in two 'lights' you will need to connect them in series. (As long as the current supply can go high enough for account for the forward voltage of all the LEDs)

 

[crazybry79]

Gotcha....
LEDs in series within the light. Lights in series to make 1 circuit. Ad Voltage. Got it!

 

[crazybry79]

Wait..... that would put me at 90V.... and that's on the lowest forward voltage.

Could I run the LEDs in series within the light, but run the lights parallel?

 

[Gryd3]

Wait..... that would put me at 90V.... and that's on the lowest forward voltage.

Could I run the LEDs in series within the light, but run the lights parallel?

In theory yes... but in practice it would be a bad idea.
Remember from before, the LEDs are all a little different.
If one of your 'lights' is actually a lower forward voltage than the other, then it will draw most of the current which could be too much. This will damage the lower forward voltage 'light' and cause the other 'light' to be dimmer. Also, if one 'light' fails, the current supply will attempt to continue shoving the same amount of current for two 'lights' into the remaining light... which would most likely kill it in short order.
So.. the option here would be to try making a 'light' with only 4 LEDs, look for a more capable current supply, or risk it and put a 5-10Ω on each light to attempt to help keep them more balanced.

 

[crazybry79]

Actually, I never thought of it.... I can go more watts now that I'm upping the voltage. That will give me less LEDs for the same amount of fish happiness....

Hmm...creativity and eBay in action.

 

[crazybry79]

Hold it.... can it REALLY be this simple?

One 600w power booster/regulator.

One of these on each side. Wired in series?
http://pages.ebay.com/link/?nav=item.view&id=331258892673&alt=web
As a bonus, more fish pleasing lumens...

36V x 2= 72V. Easy not so cheesy!

Did I miss something?

 

[Gryd3]

Actually, I never thought of it.... I can go more watts now that I'm upping the voltage. That will give me less LEDs for the same amount of fish happiness....

Hmm...creativity and eBay in action.

Looks that easy to me.
You've taken the highest possible forward voltage (36v) and used that for you requirements calculation, and the current supply you have goes up to 80V giving you a little head room.

Current of each LED is 3.5A, which again, the supply states it can handle much higher.

I may end up ditching the 10Watt LEDs I have here and getting those as well XD

 

[crazybry79]

Well hot damned!

I can't thank everyone enough!

Busy clicking buy it now! Photos to follow!