Make your own 4AA P60 host: PT 40 mod

I had several unused P60 bulbs laying around and was wondering how I could use them without going through $$ of primaries. I also noticed they are selling relatively cheap in the Marketplace, so I thought it would be ideal to have a 4x AA host to run them in guilt free. I have always thought the Princeton Tech 40 was a good candidate for modding. I didn't notice any threads in the archive on this, so I thought I would give it a go. I used an older PT 40, so I have no idea if the newer versions have the same internals. Test host:




First thing I did was remove the lamp assembly.



With a pair of needle nose pliers, remove the negative terminal screw as shown (twists out):



Drill a third hole (as shown on the far right) to make contact with the outer spring of the P60. Insert a screw slightly longer than the screw removed into the drilled hole:


Should look something like this when finished:


The screw should come out in a place that could make contact with the outer spring on the P60 lamp (right side of picture). Use a dremel to remove the plastic cylinder in the middle of the module as shown. Place epoxy over the end of the positive screw (left side of picture) to prevent contact with the outer spring on the P60 lamp:



Purchase a 3/4 inch PVC end cap at a hardware store ($.36 at Menards). Cut off a ring 3/8 inch deep:



3/8" ring with P60:



This ring keeps the P60 centered in the bezel:



Add some glow paint to the ring if you wish (drill holes for tritium, whatever). I get about 1.5 hours runtime on a set of eneloops. I have run the P60 for 3 hours straight, there is no damage to the plastic lens. The twist on/off function still works somewhat with the mod, but may not depending on your screw placement. Enjoy!

Interesting mod.. thanks for sharing!
I dont own any of those lights, nor any of those bulbs, but great to see people trying new things.
I wouldve probably upgraded to a Led.

Hi, ChibiM

I suppose if I were to make the 3/8" ring out of aluminum or copper instead of PVC, there probably would be enough mass to use this mod for a P60 LED module.

Are you planning on doing that, or will you keep it as is?

Hi, ChibiM

Thanks for your question. I plan to keep it as is for a while, I made this modification to burn through unused P60 incan lamps that I have no other use for. Since those get 30+ hours of life, and I still have a handful of them, it will take me a while to use them up. I have plenty of other P60 hosts with various battery configurations, but none that were 4AA. This is a relatively inexpensive and easy mod for anyone who wants a P60 host that is a great form factor, waterproof to 100 meters, polymer (nice for the winter), and feeds on rechargeable AAs.

? 30hours?
I wasnt aware of that..
that doesnt seem to last so long then!

leukos said:

Hi, ChibiM

Thanks for your question. I plan to keep it as is for a while, I made this modification to burn through unused P60 incan lamps that I have no other use for. Since those get 30+ hours of life, and I still have a handful of them, it will take me a while to use them up. I have plenty of other P60 hosts with various battery configurations, but none that were 4AA. This is a relatively inexpensive and easy mod for anyone who wants a P60 host that is a great form factor, waterproof to 100 meters, polymer (nice for the winter), and feeds on rechargeable AAs.

Click to expand...

Yes that is awesome. At one point I was really wanting a 4aa host for p60 incan lamps, that wasn't a mile long tube, or cost $150 for a semicustom side by side setup. Nicely done.

I have done similar mod with Responder 4AA which has same configuration to above flashlight but uses PR base bulbs and I installed 4 volt auxial bulb which is drawing about 3.3 Amps. This is much brighter but run time is short.
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ChibiM said:

I would've probably upgraded to a Led.

Click to expand...

LED in polymer body?
It's not a good idea unless your LED is underdriven.
Voltage of 2 primary lithium 123 is about (2x2.5) 5 volts under 1.2 Amps
Voltage of 4 NiMH AAs are also about (4x1.25) 5 volts which is perfect for P60 lamp module.
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ChibiM said:

? 30hours?
I wasn't aware of that..
that doesn't seem to last so long then!

Click to expand...

Most of Surefire and other brand incand flashlight bulbs are rated about 25~40 hours of life which is calculated if bulb is running at full voltage. (5 volts for P60). In fact bulbs run at that voltage for few minutes of fresh cells then drops to less voltage and bulb runs more relax with longer life.
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Well said, FM. Not all of us want to turn everything into an LED, well driven incans are still the most pleasing light to my eyes when I am walking around outdoors.

Led in a polymer body? why not!
No, you don`t need to overdrive it.. just normal.. like the Jetbeam PA40. Still doing a few hundred lumens... and for many hours.

Im definitely not an incan guy, and probably wont be any.. although I dont mind trying something new out. (all the incan lights I had in my life were not very interesting)

ChibiM said:

Led in a polymer body? why not!
No, you don`t need to overdrive it.. just normal.. like the Jetbeam PA40. Still doing a few hundred lumens... and for many hours.

Im definitely not an incan guy, and probably wont be any.. although I dont mind trying something new out. (all the incan lights I had in my life were not very interesting)

Click to expand...

(yourine the incan forum)

This great information for those of us who still have many P60's lying around not being used.

Thanks.
.