Need mod suggestions (bike head lamp)

Friend is an avid biker, and he knows of my hobby for flashlights, occasionally modifying them as well. Here is his 'Nite Hawk K2', what little I know about it, and some questions. The object, of course, is to provide more and better light.



- helmet mounted, was made in Canada but no longer in business, so info on it is sparse
- approx 4 years old
- runs on external pack of 5 NiMH, fresh off the charger at 6.8v.
- 3 level driver, draws .90a on max.
- uses solid optic, ~ 34mm diameter X 20mm high
- emitter - Cree, what? Can you tell what emitter this might be from the picture?

Possibilities - My first idea is to replace the emitter with something newer, at least an XP-G R4 with decent tint, and hope the optic works OK with it - I would try the optic before changing emitters. Or would some other emitter be more likely to work with this optic?

- or, rip out the guts, rig it to work with a triple XPG + optic. Mount a d2flex and hipCC or other suitable driver in with the battery pack (maybe 4 serial 18650's) instead of in the head, provide a sub-mini momentary switch to attach to chest area (the battery pack is worn in the back pocket of a cycling jersey.)

If I just change the emitter, what are the chances I could get by running the existing driver with 8v (4 18650's s/p) instead of the stock 6v+ without poofing the driver? His battery pack is stale & I'd like to replace it with 18650's if possible.

I've got an Osram Ostar 6-die emitter laying around, fV around 20v, as well as a 34mm reflector for it - rip out the guts, make a custom spacer / heat sink the correct height for the shallow reflector to sit properly in the housing, use 4 serial 18650s with an appropriate boost driver built into the battery pack, run the Ostar at 1a or a little less.

Any other easy or not so easy mods you can think of for this? Any ideas at all are welcomed. What would you do? Thanks,

John F

I would venture to say that an R5 would be an easy mod...but it would be a bit too spotty for trail riding. I was riding with an R5 and felt it too tight. P7 was much better "all-around".

Why not retro a P7 in there and keep the Ostar for something rediculous for yourself:huh:

Well, he rides road bikes only, so spot is good, flood is mostly wasted. I do agree that the P7 would be nice, but with the existing driver, it'll only be driven at less than 1 amp. At that current, I'd guess that an XPG R4/R5 would be at least as bright or brighter.

That LED is a Luxeon III. The easiest mod would be to unsolder the Luxeon and solder in a Seoul P4 emitter. (I just bought a few U3SVNH binned P4s from PhotonFanatic, and I've been very happy with them). This should (roughly) double your lumen output, and will probably work with the stock optic.

Running the light off of the 18650 combination that you suggested shouldn't be a problem... EXCEPT that you'll be depending on the protection circuitry of the battery pack to prevent overdischarge (because the vF of the LED is so much less than the voltage of the battery pack).

Wow, a good 'ol P4, eh? I happen to have a few good ones in the drawer, it'll be easy, so worth a shot. At least the tint will be much better. I have the little protection boards from batteryspace I'd use for a lion pack, so wouldn't have to worry about the friend ruining a bunch of 18650's.

Thanks for the ID of that emitter, now that I think about it the P4 should be noticeably brighter. But, still maybe not a real step up enough. I'll try it before proceeding to the next level...

The other issue, that I can't tell from your pictures, is the body plastic or metal? Anything more than a P4, probably not gonna be able to deal with the heat properly, other than possibly an XP-E/XP-G, but then you have a whole different problem mounting that emitters in there.

The P4 would be the best for that, just make sure you isolate the bottom of it, or make sure that the contact point underneath isn't connected to anything (like ground).

wildstar87 said:

The other issue, that I can't tell from your pictures, is the body plastic or metal? Anything more than a P4, probably not gonna be able to deal with the heat properly, other than possibly an XP-E/XP-G, but then you have a whole different problem mounting that emitters in there.

The P4 would be the best for that, just make sure you isolate the bottom of it, or make sure that the contact point underneath isn't connected to anything (like ground).

Click to expand...

He's only changing the emitter, not the drive levels. If anything, because of the increased efficiency of a more modern emitter, output will increase and heat will decrease.

chelboed said:

I would venture to say that an R5 would be an easy mod...but it would be a bit too spotty for trail riding. I was riding with an R5 and felt it too tight. P7 was much better "all-around".

Why not retro a P7 in there and keep the Ostar for something rediculous for yourself:huh:

Click to expand...

Actually, because of the larger die size from the luxeon to the XP-G (I believe) keeping the stock optic will result in a larger beam pattern.

Right, I know that, I was referring to going to a P7 or something like that. I did say "anything more than a P4".

John_Galt said:

He's only changing the emitter, not the drive levels. If anything, because of the increased efficiency of a more modern emitter, output will increase and heat will decrease.

Click to expand...

wildstar87 said:

Right, I know that, I was referring to going to a P7 or something like that. I did say "anything more than a P4".

Click to expand...

Ah, gotcha...

wildstar87 said:

The other issue, that I can't tell from your pictures, is the body plastic or metal? Anything more than a P4, probably not gonna be able to deal with the heat properly, other than possibly an XP-E/XP-G, but then you have a whole different problem mounting that emitters in there.

The P4 would be the best for that, just make sure you isolate the bottom of it, or make sure that the contact point underneath isn't connected to anything (like ground).

Click to expand...

The body is all aluminum, I think it'll take a good bit of heat (there is a tight-fitting finned piece you may not see in the pic.)

John F

That emitter is a Luxeon emitter. I had the same emitter in a Niterider MiNewt that was a few years old.

I ordered a SSC P4 U3 bin LED from Photon Fanatic and the amount of light almost doubled. It was quite impressive. It is a direct replacement for the existing luxeon that you have.:twothumbs

I did a little bench testing last night after dark. A U2SWOV P4 focused with the optic very well, but was only barely noticeably brighter than the old LuxIII (but much better tint.) A U3 might be slightly brighter still, but maybe still not enough difference.

I ordered one of the triple XP-G R5 modules with 32mm optic last week, I think I'll wait until that arrives and see what the depth is like for this housing. I may rip out the (very nice) stock driver and see about custom-fitting this triple module if it looks like it might fit depth-wise.

The stock driver has a metal pad in the middle that the emitter is mounted to for heat transfer to the body. This means I won't be able to fit a taskled driver in the body, it'll have to be part of the new battery pack if I go the triple XPG route.

Or, I might just put it back together as is and give it back to him...<g>

John F

baexmeyer said:

That emitter is a Luxeon emitter. I had the same emitter in a Niterider MiNewt that was a few years old.

I ordered a SSC P4 U3 bin LED from Photon Fanatic and the amount of light almost doubled. It was quite impressive. It is a direct replacement for the existing luxeon that you have.:twothumbs

Click to expand...

I'll order one and try it before I decide on something that will wind up taking far longer and be more expensive than I could anticipate. Thanks, close to double the light would be great.

John F