Petzl DUO caving light modification

Today I started Working on the light :)
Sine I want to restore this light for a long time I did some research a while ago and figure out that to enable decent brightness I will have to allow the heat dissipate from the sealed body using an external heat sink so the first step was to remove all the old components from the body and make some place for the new components and heat sink



1. Take everything apart


2. I mean everything


3. Remove unnecessary plastic supports (don't worry I will add Aluminum supports instead)


4. make place for a rear heat sink


5. And now it is ready for the new components


It is the big challenge in this protect I hope I will mange to do it Although I don't like using glue, I think that it is the best option for this mission.

With my wood lights, I sometimes joke that I don’t worry about making them waterproof because the glue I use is not waterproof. :wink:

Looks like a good start.

Thanks for the reserch. I came to speleology only 10 years ago and have not seen duo era. Very interesting.

Good to see you are making a good light for caving, YuvalS. :+1:


A waterproof wooden lights sound interesting, consider use another glue :)


I still see some cavers using them, mostly with the CustomDuo inserts but they are rare now


That is the only type of lights I build

Had some progress with the body today.I cut 4mm aluminum I had at home to the shape of the internal space of the light in order to have some mass to absorb the heat and conduct it to the rear end where I will place the heat sink.


Cut cardboard templates


Saw it using a Jigsaw


First I glued it in place with heat resistant RTV


Then I glued it with headsink plaster


And clamp everything together till it dry

I use the hide glue because it cleans up very well. The waterproof wood glues can appear to have the squeezed out glue cleaned of completely but sometimes when one clear coats (or stains) you see a difference in coloration where there was a dried and near invisible film of waterproof glue. It doesn’t always become apparent until too late, after clear coat has been applied.

A water proof wood light might float. Could be a cool idea. Maybe I’ll have to think about that one. Include a motor and propeller/fan that could cool it in air?


I spend a lot of time waiting for wood glues to dry.

A bit more progress today:
I had to file the heat sink so it fits to the roundish shape of the light and the helmet and also to add small piece of aluminum to fill a small gap left a the side of the light


Using the cardboard technique to find the correct shape for the heat sink


Fitting the aluminum piece for the small gap


Gluing everything with thermal plaster

And waiting....

:+1:

After the Heat sink plaster cured, I did s bit more sanding to fit it perfectly to the helmet mount (had to leave a small gap to allow airflow to help with cooling.
I also drilled the place for a 12 mm waterproof momentary switch


Then, I drilled a hole for the switch wires (winch I forgot drilling before gluing :facepalm)


And (as promised) sealed all gaps between the aluminum and the original body with glue to maintain waterproof

That heatsink looks nice, definitely better than only plastic.

Good job with cutting and squeezing in the aluminium heatsink parts. :+1:

Good to see progress.

I’ve been stalled.

I took a break from working on the body and moved to the battery box.
Although the body is more interesting, the real challenge for me in this build is the battery box since it was designed for 4*AA batteries and the it is really hard to squeeze bigger 18650 cells into it.
another problem is the contacts, since I want to use 3.7V, one contact have to be placed on the lead and I have to find a way to wire this contact to the bottom part. I really have no Idea how to do it without risking with contacts or wiring problems.

Anyway, the first step was to remove all the old AA parts. Because the plastic structure is deep and none of my tolls was able to remove all the old parts and make place for 18650 I had melt the plastic at the bottom of the box using my old soldering iron (did it in a well ventilated place to avoid birthing melt plastic :) )


Original AA contacts


After melting the bottom parts


Not enough place for 4 cells

This project is up my alley! I’ve modded/retrofit l9ghts from incandescent to LED and it’s not easy so great job so far. For the batteries have you considered using 14500’s? They are not as high capacity as 18650, but you can use them in parallel for more capacity. Or just use 3 18650 unless you need series or series/parallel.

Imagine 8 × CR123As… :laughing:

(16mm, not 18mm.)





Thanks Guys.
I have chosen 18650 cells for few reasons:
First, I have tons of 18650 from old laptops so it is practically free.

But more important, in caving we always carry 2 or 3 lights for backup and spare batteries for each light. So it is easier when all lights are running the same battery size so I only have to carry one type of cells.
Single 18650 headlamps are very common and I have few so it make sense to use 18650 for this light too. It also allows me to borrow cells from friends in the cave in case I am running out of cells
It is also the reason why I chose no to use 1S2P pack that can solve a lot of problems and make the built a lot simpler.

Nice, “planning to change EVERYTHING”. Looks like an epic modification :person_with_crown:

Building a boat, are we?


Tanks PP, everything but the host :)


We should have a Budget boats forum