Science project of the month - 100W underwater LED

[simplysanj]

CAUTION: Don't try anything like this unless you know what you are doing.

I was a little hesitant to post this until I had some safer results but here it is. People that know me know that when I start a project it always has to go a little too far. I wanted to put underwater LED lights on my boat but found that they were either really expensive and/or not especially bright.

With a little understanding of electronics, LED drivers and chips from ebay, lens and bezel from Aliexpress and a custom aluminum backing plate made at emachineshop, I finally got this bad boy to work and run cool underwater. I have also machined standoffs so the backing plate is not directly on the gelcoat and has water cooling on the backside. Runs at around 5 degrees hotter than the ambient lake water which is amazing.

Cost of materials for each is probably under 100 bucks and a couple of hours to assemble. I don't have pictures of the failed prototypes but will post them later.

I will put 4 x 100w on the back of my boat next spring and 6 x 100w on my dock.

Assembled unit:


Out of water smoke test:


Pot of water test:


Lake test (in daylight):


Luminosity in broad daylight:

[mnwakerider]

Looks sweet. How big are they? How far does the lens protrude? What kind of angle does that lens make?

Wanna make some more???

[simplysanj]

Looks sweet. How big are they? How far does the lens protrude? What kind of angle does that lens make?

Wanna make some more???

It's roughly palm sized, here is a reference with a slightly smaller lens:



If you would like I can order extra parts when I put together the next batch and get them to you at cost. I won't assemble them for anybody since it's fidgety and frankly can be dangerous if done wrong.

[nyryan2001]

doing rough calculations....

100w divided by 12.6 = 7.93 amps

as a comparison to Lifeform 9 specs: (2.7Amps @ 12 Vdc) 32 Watts gets you 2600 lumen

So these should be roughly 3 times brighter.... like in the range of the new 10k Lumen Roswells.... thats sell for $1000 a pair. Quite a deal for a $100 DIY project.

[simplysanj]

Parts List

I've been asked for the parts list privately so here it is. I am very happy to share the parts list but I would advise you to wait a little while before building so I can document the build a bit better and also I will make available custom backplates so you don't have to machine them.

Here's the list:


$10.80
66mm lens and pressure ring
http://www.aliexpress.com/snapshot/6182974473.html


$14.00
100W LED
http://www.ebay.ca/itm/100W-royal-bl...40f3b01&_uhb=1

$17.00
100W DC LED driver (I haven't fully tested this one)
http://www.ebay.ca/itm/261493174933?...84.m1439.l2649

Custom:
$25 ea
Aluminium backplate and standoffs machined by emachineshop.com


Other:
- JB Weld high heat epoxy
- Silicone thermal heat paste
- Silicone sealant
- Stainless screws

Cheers!
Sanj

shameless plug -> http://www.vrbo.com/200970

[MLA]

Just for chits and giggles, what is the DC amp draw of this LED assembly? This puts any and all advertised specs to bed.

[simplysanj]

I will verify current draw this weekend when I am back at my basement lab. I have ordered a luminosity meter to validate too. The blue doesn't put out as much as the white for the same wattage BTW. I really doubt that there are any true 10000 lux coloured led lights available as the CREE chips would take a square foot and nearly a thousand watts to do so in any color other than white.

[simplysanj]

Bench test

I received a Victor 1010A luminance meter today which is supposed to be relatively accurate to about 3% at 10000 lux so I did some tests on the white COB 100W LED that I had lying around, here's what I measured

WHITE 100W LED - 32VDC, pushed to 3.5A, about 112W (measured at input of LED chip)

LUX at 1M: 6500 without lens, 14500 with lens (!!!)

Bright as the sun! I will retest with blue LEDs next week.

[MLA]

So this is not a 12V light assembly, hence the need for the controller?

[simplysanj]

So this is not a 12V light assembly, hence the need for the controller?

High power LEDs need constant current and voltage to run efficiently. For a 100w COB , +-30v and 3a is the right combo. The blue box is an LED driver that takes 12v in and boosts it up to 32v. Current and voltage are adjustable with tiny trim potentiometer s.

So, yes you need a driver such as the one above to run off 12v.

One correction, its lumens and not lux that I measured.

[MLA]

High power LEDs need constant current and voltage to run efficiently. For a 100w COB , +-30v and 3a is the right combo. The blue box is an LED driver that takes 12v in and boosts it up to 32v. Current and voltage are adjustable with tiny trim potentiometer s.

So, yes you need a driver such as the one above to run off 12v.

One correction, its lumens and not lux that I measured.

That i understand. I typically deal with 12V ready LEDs that do not require any external controllers. So in order to put htem into perspective, I was curious what the 12V current draw was. So that would be pre-controller A's.

[simplysanj]

That i understand. I typically deal with 12V ready LEDs that do not require any external controllers. So in order to put htem into perspective, I was curious what the 12V current draw was. So that would be pre-controller A's.

Prolly around 11a as the driver is pretty efficient

[jchamlin]

Cool project. The high costs of the current, popular LED's are crazy when the material costs are relatively low. I guess with anything, gotta pay for dev costs. Thanks for sharing your project.

[obd666]

great work. will keep an eye out for more detail on your build out and more testing, but i am definitely interested in maybe doing a couple on my boat. everytime i start to add some over the counter LEDs i end up finding somewhere else to throw $600, lol

[simplysanj]

Thanks and update

jchamlin, obd66: Thanks for your encouragement, sometimes I think that nobody cares about my weird science!

Here's an update:

1) I measured the 100W blue LEDs through the directional lens housing and get a reading of 6000 LUX at 1 meter. This is awesome! LUX (lumens per square meter) is the correct reading and not just lumens, my mistake again.

2) The blue 32V voltage boost converter is cheap, works great and doesn't heat up much so this is good news.

3) I have a new low profile version of the base plate and standoffs that will be sent to the machine shop next week, I'll run about 30 of them so I can share with friends (picture enclosed).

4) Grant West did a great review of commercial lights on the WW forum: http://www.wakeworld.com/forum/showthread.php?t=702750


Blue Sun V2: