# 100000 Lumens, 100 Watt LEDs in Parallel, 24 Volt DC Circuit



## Gigger (Jun 8, 2015)

https://ledcircuit.shutterfly.com/pictures/9


Questions:
· Am I being too aggressive with my resistors. Current formula is at 35V/3A ~ 12 Ohms and 100 watts. I could set voltage at 33V output and go to 11 Ohms and 99Watts. Voltage max cannot go over 35 anyways. I am worried about losing too much in my resistors.
· Does my booster allow me to regulate current as well so I would not need resisters; it looks like more of a voltage regulator with a Max 10Amps?
· Should I put current drivers on each parallel circuit rather than resistors, that way if one blows I should be able to regulate current rather than blowing the whole string?
-> I am not that worried about blowing the whole thing because I have a breaker. And even if a blow the string I plan on having 3 others in the water to use as backup…
· For the switch panel I wasn’t sure if I could put my own fuses in there at 9 amps?
· I am thinking that if two batteries have around 200 combined amp hours? Any suggestion on this to ensure we have enough juice to run these. Running all four in the current scheme would give us around 5 hours, I am thinking we may not be running all 4 all the time depending on what side we are hitting up.

Any suggestions on how to do this more effectively are welcomed. It seems like I am pushing the higher limits on all of this stuff with the current Schematic, but I want maximum output for the lights.

*Diagram*
A) Switch Panel ($37)

B) Driver ( $8)
C) Resistor (3X3 = $9)
D) LEDS (4*3 = $12)

I plan in running 4 of these circuits off the switch panel.
So that would be around $160 (exclude housing & wiring) for a Maximum *108,000 lumens*


I am handling heat sync on a separate thread.
I am probably going to heat sync drive, resistors, and LEDs to an aluminum Square Bar/Plexi and have everything under water, so it will be water cooled.


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## RetroTechie (Jun 8, 2015)

Welcome to CPF, Gigger! 

First off: pics would be welcome, link given doesn't work (requires sign-in).
Second, if I read correctly you plan to use 3 LEDs (each one _rated_ at 10,000 lm max output). That's 30,000 lm max output, not 108,000. _If_ those bottom-of-the-barrel-priced LEDs perform as advertised (doubtful).

Also I'd have my doubts whether such a cheap DC-DC converter would actually convert 100W _and_ survive for an appreciable length of time. But maybe that's just me. If I read its specs correctly, it can be set as a constant current source, but only provides enough output voltage to drive one LED. And only enough output _power_ to drive one 100W LED anyway. As a voltage source, the resistors would be calculated as (output voltage of DC converter - voltage over the LED) / desired amperes _through_ LED. Depending on the LED's characteristics, with this DC-DC converter, probably _in the order of_ 1 Ohm in series with each LED. Possibly less. So your calculation is incorrect & way off.

Otoh, those switches seem rather expensive. You don't need anything special to switch a few A @ 35V.



> I am not that worried about blowing the whole thing because I have a breaker. And even if a blow the string I plan on having 3 others in the water to use as backup…


What is meant with "having 3 others in the water" ? 

With water cooling, you mean everything under water? :duh2: Or just the heatsink? And how would that water get rid of the heat?

Your post could do with quite a few clarifications... intented power source(s), perhaps a schematic, picture of an example what you have in mind, intented uses, hand-carried or fixed to a vehicle? Etc.


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