alternative for Luxeon Star LED - White Side Emitting, 40.5 lm @ 350mA

[steveG]

Hi all,

I have a stash of Rayovac 3 in 1 headlamps (uses 3xAAA) that have the mostly useless incandescent bulb and reflector. I've read about the mod Lux Luther came up with here: http://www.candlepowerforums.com/vb/showthread.php?t=12669. It's straight forward and simple, so I thought I'd order a few LEDs, install them in the lamps and stash them in my cars for emergencies.

That thread is six years old, so I figured by now there might be an LED that could do the job more efficiently than the LXHL-FW1C.

Anyone have a suggestion? Should I just use the LXHL-FW1C? If so, should I use a resistor?

Thanks in advance!



P.S. This is the lamp:

http://www.amazon.com/dp/B0007XJQK0/?tag=cpf0b6-20

 

[mdocod]

I'm assuming that the side emitting LED was chosen because it works well with the reflector, but I'm betting that with some experimentation with LED position, you could get just about any standard star mounted LED to work with an acceptable beam pattern. The old Luxeon series were only around 40lm/w give or take, now days, there are high power LEDs that are pushing 100+ lumen for that same 1W drive level, the Cree Q5 is pretty much the mainstream right now in flashlight applications and is what I would suggest *trying* to use. (Or a Q2, which is slightly less efficient, but probably cheaper).

More than likely, you'll have to play with the "focus" in the reflector. Might have to shim the LED or the reflector, might have to drill out a larger hole, hard to say...

Another issue is that the Vf of modern LEDs may be lower than back then, which may cause higher current to flow across the LED, so you might want to consider a resistor of sorts in series with the LED from the batteries to control current flow, trial by error with a current meter would probably suffice with a few resistors to play with, with any luck, maybe another more experienced member in this area could suggest how much resistance would be a good starting point. You could always measure it direct drive to see where it's at first, if it's already at ~300mA then it should be ok, but ideally, I'd shoot for lower since the only heat-sinking available is the star itself within the headlamp. 250mA or less would be more appropriate IMO.

Hope that helps, best of luck with your modification

Eric

 

[steveG]

Yes it helps. Thank you!

It does seem that the side-emitting LED was chosen to work with the reflector. The instructions in the thread say to drill the reflector to 5/16" to work with the LXHL-FW1C.


Maybe I should try this Cree XR-E Q5?

http://www.dealextreme.com/details.dx/sku.2394

Can someone give me a recommendations on a resistor (or assortment of resistors) to start with?

 

[phantom23]

SSC P4 is direct replacement for old Luxeon. It has the same beam pattern.

 

[mdocod]

Hi phantom23
The SSC P4 has a similar emission pattern as the old "standard" luxeon, I think it was called the lamberton, the side emitting luxeon being discussed here is completely different and a P4 is not a direct replacement in any way as far as emissions are concerned.

SteveG, The P4 is however, may be a better choice because of it's smoother transitioning in the emission pattern. But it's not as efficient.

I think I'd try something with that Q5 first, and see what you can come up with, I can't guarantee anything though

.... or you could just order an old side emitting luxeon, but man, that would be giving up a lot of potential IMO -------

Eric

 

[steveG]

I can't guarantee anything though

Well, I'm going to need you to come up with something you can guarantee. Haha.

.... or you could just order an old side emitting luxeon, but man, that would be giving up a lot of potential IMO

That's exactly what I asked before ordering. I guess I need to do some research on resistors....

 

[LukeA]

I would use an SSC P4 and I wouldn't use a resistor.

The SSC is a better physical fit than a Cree, and its lambertian beam pattern will work better in the stock reflector than the Cree's pattern which focuses more light forward.

 

[steveG]

I would use an SSC P4 and I wouldn't use a resistor.

The SSC is a better physical fit than a Cree, and its lambertian beam pattern will work better in the stock reflector than the Cree's pattern which focuses more light forward.

Like this one?

Seoul Semiconductors Z-Power LED Emitter (U-bin)
http://www.dealextreme.com/details.dx/sku.1445

Or this one?

CREE P4 LED Emitter (WD)
http://www.dealextreme.com/details.dx/sku.1302

What's the difference...? Sorry for the ignorance, I'm new to this and it's still confusing!

Many thanks!

 

[mdocod]

that's a good point, it may be easier to shim the LED into position with the base of a P4 emitter rather than the rectangular base of the XREs,

 

[LukeA]

Like this one?

Seoul Semiconductors Z-Power LED Emitter (U-bin)
http://www.dealextreme.com/details.dx/sku.1445

Or this one?

CREE P4 LED Emitter (WD)
http://www.dealextreme.com/details.dx/sku.1302

What's the difference...? Sorry for the ignorance, I'm new to this and it's still confusing!

Many thanks!

The top one.

 

[Gunner12]

The top one is the Seoul(company) P4(model) U-bin(flux bin).

The Cree(company) XR-E(model) P4(flux bin)

The bottom one has the same emitting pattern as the Cree XR-E Q5, just at a lower output and efficiency.

 

[steveG]

I thought I'd give everyone that helped an update. I ordered and received this LED: http://www.dealextreme.com/details.dx/sku.1445, installed it in the lamp and it works great, For a bit I thought I ruined the emitter. It started strobing and doing some weird stuff when I would connect to one of the contact pads. I accidentally found that it worked fine when I attached the negative wire to one of the screws so I ran with it.

You'll have to excuse my poor workmanship and speaker wire (it was the thinnest I had). I don't solder often and never on such small parts. I also figured out that I need to invest in some better soldering equipment.

I'm very happy with the amount of light. Without the reflector it puts out about as much light as my H30 Zebralight at a slighter wider angle. It's certainly no thrower, but hey, neither was the original incandescent. I did try the reflector but there were a ton of rings in the beam. I may play with that part later.

EDIT: Not as bright as the Zebralight, see my next post.

 

[Gunner12]

Yay! I'm glad it worked.

You would have to get the reflector in focus.

Since most incan lights have the filament pretty far into the reflector, you might have to remove a good bit off the bottom of the reflector in order to place the LED at the focal point.

 

[spencer]

I have a few headlamps like this as well and I'm interested in what you did.
As far as I can tell you just did a complete replace of bulb for the LED. Is that correct?

Thanks,
Spencer

 

[steveG]

As far as I can tell you just did a complete replace of bulb for the LED. Is that correct?

Thanks,
Spencer

Yup. It was very straight forward. I'm going to order a few more to convert my other headlamps. I still want play with the reflector to see if I can get some throw out of it.

EDIT: I ended up with just over a 3/8" hole and the focus and throw are great. I would start there, or just under, and adjust accordingly. The reflector snaps into the lens cap and turns as it's threaded down, so be careful that it doesn't tear up the terminals on the emitter.

Update on the output. I took it outside just now and it's definitely NOT as bright as my Zebralight. It's a good amount of light and very usable, but I have to be fair to the H30. I have no idea about lumen output, but regardless, a good upgrade indeed!

 

[steveG]

I got a few more LEDs and got a much cleaner job done. I thought I'd post more pics. I'm also doing a runtime test with some rechargeables. I'll post the results later.

By the way, earlier today I saw these lights at my local Big Lots for $8.00 each.

Pics:

 

[mdocod]

looks like you're having fun. Good call on the U-pin P4, that's a more modern P4 and should be right up there with some of the latest and greatest.

I do suggest a current measurement to the LED to make sure you aren't driving them too hard. (or even from the batteries, and from there a rough estimate). Just want to make sure since the only heat sinking is basically just the star, and that is mounted inside of insulated plastic, that it doesn't overheat and self mutilate. When they get too hot they will go into thermal runaway

 

[LukeA]

looks like you're having fun. Good call on the U-pin P4, that's a more modern P4 and should be right up there with some of the latest and greatest.

I do suggest a current measurement to the LED to make sure you aren't driving them too hard. (or even from the batteries, and from there a rough estimate). Just want to make sure since the only heat sinking is basically just the star, and that is mounted inside of insulated plastic, that it doesn't overheat and self mutilate. When they get too hot they will go into thermal runaway

If the original emitter didn't self-destruct, then this SSC which produces slightly less heat than the Luxeon, will definitely be fine.

 

[steveG]

It looks like I'll be OK on heat. I left the light on for 3.5 hours yesterday and saw no adverse affects from heat. I checked on it regularly and it was never very hot. My H30 Zebralight gets MUCH hotter when ran on high for extended periods.

P.S. I may play with adding a small resistor to decrease brightness and increase usable runtime.

Any starting suggestions?

Thanks again for the help guys!

 

[mdocod]

If the original emitter didn't self-destruct, then this SSC which produces slightly less heat than the Luxeon, will definitely be fine.

The original mod replaced a bulb if I'm not mistaken, which means it would likely be direct drive.

As for the LED light with the updated Seoul, it's very possible to get a Lower Vf LED. This would result in higher current flow from the same original setup.

Eric