4200 lumen can light

[kelemvor]

I am nearly finished with my dive light project. It's neutered at the moment, only running 50w when it was intended to run at 100w.

Basically I took a defunct OMS halogen/LeadAcid can light and converted it to LED/Lithium. Although the LED chip is supposed to be 100w, the math says it's really only a 50w chip. I've got a 150w capable boost converter set to output 32.000v. Input at the moment is a 12v 3200mah 30c lipo. I haven't bothered to run test it yet because I'm going to use a much larger battery. I've also got a replacement LED chip on order to get it up to the intended 100w.

Specs on the chip are 100w/8400lumen so at 50w I'm guessing it's only producing 4000 lumen.

I need to improve thermal contact with the light head. Currently only the corners of the chip heatsink are contacting the head. There is fair thermal transfer occurring but it could be MUCH better. I suspect I'll have to design a 3d printed prototype heatsink spacer and then send that off to be machined in aluminum.

It has a beautiful and bright flood spill pattern. I can't really measure the output but it's considerably brighter than the handful of other lights I've got all rated at 1000 lumen.


I'm using this stuff:
100w LED: https://smile.amazon.com/gp/product/B01CU0NWD4 $11
44mm reflector: https://smile.amazon.com/gp/product/B01CU0NWD4 $8
150w boost converter: https://smile.amazon.com/gp/product/B00C0251CS $10
Broken OMS light: from scubaboard $50
Kinexsis F-Tek 30c 3200mah 3s lipo: from local hobby shop $30

I planned to build this a couple years ago. Bought most of the parts, then got distracted. Unfortunately that means the exact listings for parts on amazon aren't still available if you were to try and duplicate it.
As the only light source in the room:
Powered on. Color temp is a close match to my 5000k room lights

Light head. Black stuff is two part thermal epoxy (MG Chemicals 8329TCS) that hasn't set just yet.

Once the epoxy is cured, I'll reopen the head and correct the mounting of the mirror.

The light head has an integral "screw" switch. Also the handle rotates to move the old socket in/out to control beam angle on the original bulb. I've simply got wires running from the old bulb socket to the LED.


It definitely needs some new O-rings, and I am thinking of switching from LIPO to LI-Ion 18650 cells as they provide sufficient current to run the chip at 100w with lots of room to spare.

I need to add a battery protection circuit in there if I don't do the 18650's With that lipo in there, the cell could drain low enough to damage the pack.

As it stands, the head gets very hot. The battery pack gets about 10f above ambient, and the boost converter gets about 15f above ambient.

 

[OTF]

That is awesome. Well done, that old head is super cool looking. Love that it has a focus adjustment.

Is there any provision for overheat protection if it's left on in air accidentally? Be careful about toasting that LED before getting it fully thermally connected.

Been thinking about doing a similar project.

 

[kelemvor]

That is awesome. Well done, that old head is super cool looking. Love that it has a focus adjustment.

Is there any provision for overheat protection if it's left on in air accidentally? Be careful about toasting that LED before getting it fully thermally connected.

Been thinking about doing a similar project.

I was disappointed I couldn't continue to use the focus feature. It would have been nice to have spot beam capability. No, currently no safety features at all. I hadn't thought of that, and will add thermal protection to the todo list. All of my other LED dive lights are just fine in air for extended times so I hadn't considered it.

It just occurred to me that I could send the light head off to have it milled out some so that it would be flat inside. Then I could pretty easily swap between chips if needed. Cree has a very nice 95CRI 10k lumen chip (CXA2 $77 Mouser) which would be pretty sweet once I get everything else settled.