So I did some research on this iconic caving lamp.

1st generation
The first generation was introduced on 1999 (I thought it was a lot earlier around mid 80's)
It had 2 light source: a 6v bulb and a 6v halogen bulb.
The light come with one replacement bulb of each type and had a special place to store them.
I could not find data on how many lumens each bulb produced but it was very low.
The halogen bulb could move inside the reflector to change the beam type.
The operation of the light was very simple move the switch up turn on the halogen, move the switch down turn on the regular bulb, switch in the middle - turn of.
 While in of mode the switch had a mechanical lock off.

    

Models:

All generation had few variations: (I don't have all the variations so these pictures are from the internet)
1. Duo - the original headlamp with rubber bands

2. DuoBelt - with longer cable and bigger battery box for 4 C cells to carry on the belt (reduce wight on the head and can keep batteries warm under the closes)

3. Fixo - to mount on a helmet.

4. ATEX - (black color) for hazardous areas (explosives etc.) 

5. Explorer - Fixo + Aceto (Carbid lamp) mounts on an EcrinRoc helmet 

2nd generation
An upgrade with 5 LEDs was introduced on 2006.
It was a simple PCD with 5 LEDs connected direly instead the old 6v bulb without any driver.
The operation was kept simple (on/off)
The PCB was also sold desperately as an upgrade to the 1st generation 
The 5 LEDe output was 40 Lumen for 28 meter and last 65 hours.
The halogen beam was for 100 meters and last 4 hours (no lumen data)
For this version also the locking mechanism for the switch and battery box was made from Aluminum instead of plastic (probably after costumers complained) 
I only have the ATEX version for this generation but of course there was also a regular version (and also belt, fixo, explorer...)

      

3rd generation
An upgrade with 14 LEDs was introduced on 2008.
Petzl kept the old halogen bulb with zoom option but offered an upgrade to the led PCB.
The PCB was a lot more complicated with a regulated current and 3 mode of operation:
Maximum: 34 meters, 110 hours, 67 Lumen
Optimum:  36 meters, 148 hours, (no lumen data)
Economic: 15 meters, 183 hours, (no lumen data)
The halogen (same as before) 100 meters, 4 hours (no lumen data)
I only have the Spelios version for this generation but of course there was also a regular version (and also belt, fixo, ATEX...)
Spelios is the successor of the explorer. 14 led Dou mounted on Elios helmet without Aceto

       

That is the actual light I am planing to modified since it is already mounted to my favorite helmet

4th generation
The last official upgrade by Petzl for the Duo was 1W LED to replace the original Halogen bolb.
since it fits to the same place it also had the zoom option 

Unoffiacal generations
Since Petzl stop upgrading the Duo light (they do make some models named DuoZ, DuoS etc. but not related to the original Duo except from the name) 
Some very talented cavers start making their own modules to upgrade the Duo.
The most famous is a British lights manufacturer John Biffin who sells them under the name Customduo.
I have 2 of his modules, 1 to replace the Halogen and one with 2 emitters

   

As you can see the limitation of this modules is heat dissipation so the maximum brightness is around 500 Lumen

This post turn out to be A LOT longer than I thought but I think it explains the history of this light and the reason it is impotent to me to keep the tradition and to upgrade this model to the most advanced LED technology.

Hope i didn't bore you too much

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 

MtnDon wrote:

I suppose water resistance is important. That gets to be a challenge for sealing and cooling at the same time while retaining the original "look".

MtnDon wrote:

With my wood lights, I sometimes joke that I don't worry about making them waterproof because the glue I use is not waterproof. Looks like a good start.

AEDe wrote:

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

CNCman wrote:

Good to see you are making a good light for caving, YuvalS. :THUMBS-UP:

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 

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....

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 

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

Sirstinky wrote:

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.

Lightbringer wrote:

Imagine 8 × CR123As... (16mm, not 18mm.)

pinkpanda3310 wrote:

Nice, "planning to change EVERYTHING". Looks like an epic modification :CROWN:

Scallywag wrote:

Building a boat, are we?

A bit more progress today with the battery box today,
I decided to use only two 18650 in parallel so I will have space in the box for wiring and the cells will sit in the center of the box to keep it balanced.
Two decent capacity cells will last a whole day of caving on low (~150 lm) to medium (~300 lm) brightness  with short periods of Turbo (~1000lm).

Placing the springs at the bottom of the box (and not on the lid) will pop the cells out so I guess it will be easier to changes cells.

First step was to create a template for the lower board
          

Than to copy it to the Prefboard (on the right is the prototype )


And cut and solder springs 


I know that many BLF members are bypassing the spring but since my "Turbo" is only 2.8A, I decided not to use bypass.
Next step is it the wiring, I have some Ideas how to connect the contacts on the lid but still not sure what is the best way

MtnDon wrote:

And if that 2.8 amps is supplied by two cells in parallel it is only 1.4 amps per cell. IMO, you don't need to bypass the springs.

Didn't have a lot of time today so I only made a small progress with the battery box wiring.

I decide to use screws terminals (not sure if it the correct English term, in my language we called it chocolate connectors since it looks like chocolate table ) for the wire connecting the battery box to the lamp.
The reason I prefer screws over soldering is that most caving lamp issues are related to the cable and using screw will allow some troubleshooting "on the field".





The black wire is for the negative pole on the lid but this will be explained on the next update... 

As promised, today I made the wiring from the power cable to the lid.
I considered many option and the two best option IMO were:
1. A dummy cell to conduct between the bottom board and the lid.
2. A wire (with or without connector)

I decided not to use a wire since I am afraid that frequent battery changes may cause contacts issues along the cable or at the soldering points and as a primary caving lamp I need to be super reliable.

For the "dummy" cell I used an old piece of Polypropylene I have from another project
  

I cut and sand it to fit inside the battery box with a small groove for the 18650 on the other side.

The top part had to be smaller to allow closing the lid


After a lot of hand-sanding it fits perfectly
You can also see the drill for the wire at the center


Currently I am planing to only use a single dummy cell and use some kind of foam to support the cells from the opposite side since:
1. It is lighter
2. It is less work
3. A foam will prevent the cells from rattling in the box.