5 watt Luxeon Star Testing, Runtimes, Brightness, ETC.

ElektroLumens · Sep 18, 2002

I thought I might start a thread to post some initial testing I've done with the 5 watt Luxeon Star. Perhaps others can also post some of their similar testing and observations here.

I mounted a 5 watt cyan Luxeon Star in a 3 'D' cell flashlight. I epoxied the emitter using a mix of 2 part epoxy and silicon grease, and wired it up, and epoxied the stock collimator and holder on the heat sink.

I modified a 6 AA battery holder to fit inside the 3 'D' cell battery compartment. It just slides right in.

With the stock optics, the beam is not a tight focused beam, but a wider beam angle, possibly 15% to 20%. With fairly new batteries, I measured 1320 lux. This is a lot brighter than that number sounds, as it is a fairly wide angle beam.

I started a test today, turning on the flashlight about 2:24pm, and leaving it on. Here are some brightness measurements.

2:24 - 1,000lux
2:39 - 1,000 lux
2:46 - 1,000 lux
3:16 - 930 lux
5:03 - 610 lux
6:45 - 570 lux
7:30 - 530 lux

I wanted to do other tests, and removed the batteries. The light is still very bright, for a Luxeon Star flashlight. But not the mind boggling brightness of the fresh batteries.

I want to see how it does with 4 cells, at 6 volts. So I now put 4 'C' cells into the 3 'D' cell flashlight, using a piece of 1" plastic pipe for a spacer, and modify the tail cap by grinding out the anodizing in the end, and put in a smaller spring.

These are fairly used, but not depleted C cells. I have some fresh batteries I will use later to do a run test.

I want to see how the brightness lasts. You know how a Luxeon Star will go on and on for days. I'm wondering if it will go on and on at a particular brightness.

So the initical brightness is at 750 lux. I'll leave it on for a while and see how the light brightness does. This is starting off well below the rated current and voltage ratings. Later on, I will do some voltage and current long term testing, but I'll have to do it with a 5 watt LS on a external heat sink.

So here it now gets turned on at 8:45pm, Wednesday evening.

8:45pm - 750 lux

To be continued . . .

Wayne J.
www.elektrolumens.com

ElektroLumens · Sep 19, 2002

Here are more results of testing this flashlight:

Testing is from 1 meter. The size of the hot spot from one meter is approx. 18", about twice that of the 1 Watt. This is not a tightly focused beam, as with a reflector in MrBulks test, so the lux will be lower. But this is a whole lot of light.

This is with 4 fresh 'C' cell batteries. All comparisons were done from the exact same distance.

8:30am - 950 lux
9:58am - 750 lux
10:58am - 630 lux
11:18am - 630 lux
1:02pm - 580 lux
2:19pm - 510 lux
3:26pm - 460 lux
5:12pm - 430 lux

After being on continuously for over 8 hours, this 5 watt flashlight is still brighter than the 1 watt mods I've done. The 5 watt is truly an amazing LED. Even underdriven, it blows away a 1 watt, hands down.

It is not nearly as bright as it can be. A good, bright light. Not hard on the emitter. No noticeable heat was ever really noticed, even with fresh batteries.

I hope to do similar tests using a reflector, which should produce much higher lux ratings.

Would this thing survive with 5 'D' cells?

What would the brightness levels and battery life be?

Wayne J.
www.elektrolumens.com

Nerd · Sep 19, 2002

Whatever you do, try not to pop these babys.....

camisdad · Sep 20, 2002

Hi Wayne - very cool - many thanks for sharing the info - it's really valuable. Michel

ElektroLumens · Sep 20, 2002

Originally posted by Nerd:
Whatever you do, try not to pop these babys.....

Well, I just cannot leave well enough alone. As I had tried 5 AA's direct drive before, at 7.5 volts, with not much detectable increase temperature, heh heh, well ... now I'm at with with 6 AA's, direct drive, at 9 volts, somewhat fresh AA's.

I used it last night for a walk, for about 10 or 15 minutes, no heat up detected. Now I just switched it on, and plan to do a brightness / battery life test. Am I crazy?

Bear in mind this is a wide area beam, not a tight focused spot. Outside, it is amaziing, it lights up everything around. Will I burn this thing up? After 10 minutes I notice a slight warming of the flashlight. I can tell when a lot of heat is being generated, having done a lot of mods with the one watt. In comparison, this thing is not even warm yet. Well, let's see if this thing will last ??

I am beginnig to think that concerns over exact current regulation, and over how much heat sink are needed, is being over rated? Why not just use a 4 'D' cell Mag Lite, put in 5 'C' cells, go direct drive! DDB, that is, "Direct Drive, Baby! "

Initial readings at the start:

10:07am - 1,818 lux
10:17am - 1,597 lux

To be continued . . .

Wayne J.
www.elektrolumens.com

Jonathan · Sep 20, 2002

I suspect that with _alkaline_ AA cells, you won't have much concern about exact current regulation. The internal resistance is quite high, relative to the 700mA rated load for the 5W beasties. With 6 cells in series, you have nearly an ohm of resistance.

A useful datum would be the actual voltage under load going to the led. 6 cells under the load of a 5W LS is _not_ 9V by a long shot. I'd bet the voltage is quickly under 7V.

Figuring out good current regulation will be important to run these beasties with NiMH cells, however.

-Jon

ElektroLumens · Sep 20, 2002

Originally posted by Jonathan:
I suspect that with _alkaline_ AA cells, you won't have much concern about exact current regulation. The internal resistance is quite high, relative to the 700mA rated load for the 5W beasties. With 6 cells in series, you have nearly an ohm of resistance.

A useful datum would be the actual voltage under load going to the led. 6 cells under the load of a 5W LS is _not_ 9V by a long shot. I'd bet the voltage is quickly under 7V.

Figuring out good current regulation will be important to run these beasties with NiMH cells, however.

-Jon

Hi Jon,

I think you are very accurate, in regards to internal resistance. It would be most helpful to know what the voltage is under load, and also, what the actual current is.

I have had problems with flashlights I've modified, when people use rechargables. Even at 3.6 volts, the rechargables have so much less internal resistance, that the current draw is too high and burn up the emitter. Seen it happen a number of times.

If I can use 5 or 6 AA's, with no additional voltage regulation or resistance, it would seem that to go to the added trouble and expense of dc/dc voltage regulators is not needed. Also, even when the batteries are low, the emitted light is still very adequate.

I will need to mount an emitter on a large heat sink, and take voltage and current measurements. With my newly purchased IR heat sensor, I can also measure the temp behind the junction point. Then we would be able to see WHY we can go direct drive with 6 AA's at 9 volts and still be okay. Right now I see it works, but I do not know what exactly is going on. Further tests will reveal this. This will benefit everyone who has purchased these 5 watt Luxeon Stars. At least, we might find the limit?

I have a 4 'D' cell Mag Lite. I feel fairly confident it will work fine, with 5 'C' cells, and direct drive the 5 watt. What a simple solution. Well, unless you want a small flashlight, that is.

After being on for over one hour, the flashlight is warm, and still very bright!

Wayne J.
www.elektrolumens.com

**DONOTDELETE** · Sep 20, 2002

Don't know beans about batery life, or LEDs.
Could you drive the 5 watt LED with 6 AAAA bateries?
Could you get 20 minutes of good light out of it?

I'm interested in small with balls.
I could get 6 months out of 6 AAAA batteries if I got 20 minutes worth of light. I don't use a flashlight often, and when I do...it's for very short periods. Thing is ....I want the flashlight on my person when I need it. A 6AAAA light would be shorter than a 2AA Mag....slightly fatter.

I would have no problem lugging that small a profile around at all times.

Please say it can be done, and Jean luc will make it so.

ElektroLumens · Sep 21, 2002

Test results:

10:07 - 1818 lux
10:17 - 1597 lux
10:47 - 1440 lux
11:07 - 1225 lux
11:31 - 1150 lux
12:15 - 426 lux

I think I'll stop here, because it wll probably go on forever at this level. I guess it could be said 1 1/2 to 2 hours of high level brightness, continuous use. I must note, that it is still brighter than a 1 watt direct drive with fresh batteries. So when do you decide to replace the batteries? When it gets down as low as 30 lumens?

Next test: voltage and current levels, using 6 AA's.

Wayne J.
www.elektrolumens.com

Glow Bug · Sep 21, 2002

Wayne,

How about a double barrel 6AA light? Could that light be heatsinked for the five watt??? I have 2 cyans dying.....thats not a good word....just begging to be placed in a good home.

ElektroLumens · Sep 21, 2002

Originally posted by Glow Bug:
Wayne,

How about a double barrel 6AA light? Could that light be heatsinked for the five watt??? I have 2 cyans dying.....thats not a good word....just begging to be placed in a good home.

The problem with the DB is the plastic in the head. If you can get direct contact of the heat sink to the metal, you might be able to make it work. I would not recomend using all 6AA's in series. I could do this with a large 3 D cell, as it started getting hot in my last test. Apparently the 6 AA's were not real fresh, that I use. When I put in fresh AA's, the light got hot.

If you used a 4 AA, or 4 AAA DB, you could probably do this, and it would be way brighter than a 1 watt.

Wayne J.
www.elektrolumens.com

ElektroLumens · Sep 21, 2002

Originally posted by Pi_314:
Don't know beans about batery life, or LEDs.
Could you drive the 5 watt LED with 6 AAAA bateries?
Could you get 20 minutes of good light out of it?

I'm interested in small with balls.
I could get 6 months out of 6 AAAA batteries if I got 20 minutes worth of light. I don't use a flashlight often, and when I do...it's for very short periods. Thing is ....I want the flashlight on my person when I need it. A 6AAAA light would be shorter than a 2AA Mag....slightly fatter.

I would have no problem lugging that small a profile around at all times.

Please say it can be done, and Jean luc will make it so.

Why not just use a 9V battery. Small! Internal resistance would help limit the current.

Wayne J.
www.elektrolumens.com

**DONOTDELETE** · Sep 21, 2002

Any guess as to how long a 5 watt LED could run on a 9V battery?

Another question...I just bought a dremel tool...It's the new rechargable. I noticed the battery after buying it ....that it's 7.2 volts.
See any problems using that battery?

Daniel Ramsey · Sep 21, 2002

There is an ever increasing market of cordless tools, of the lower end amperage or light duty the 7.2v is popular, I have a Makita 7.2 cordless drill with the recharging stand. It would most likely be what Lumileds had in mind to power this 5 watt Luxeon, Ni-Cads, which are everywhere. Makita sells a rechargeable flashlight, I believe it may be 12 volts but its a thought,

Also Wallyworld sells a bunch of inexpensive power tool kits with rechargeable flashlights as does Sears.

ElektroLumens · Sep 22, 2002

Originally posted by Pi_314:
Any guess as to how long a 5 watt LED could run on a 9V battery?

Another question...I just bought a dremel tool...It's the new rechargable. I noticed the battery after buying it ....that it's 7.2 volts.
See any problems using that battery?

If there was ever a LED the battery companies would embrace, it would be the 5 watt Luxeon Star. It does do bettern than an incandesant, but for an led it really draws the power. Only 1 1/2 to two hours from 5 AA's at hight brightness! With 5 'C' cells, I expect only 6 hours, and from 5 D cells I only expect 12 hours.

Tried my 5 C cell mod with the side emitter last night. It's on par with most any halogen flashlight. Easily lights up 100 yards away fairly bright, although it's a blue green cyan color. Can't wait for white!

Wayne J.
www.elektrolumens.com

PsycoBob[Q2] · Sep 22, 2002

Makita 7.2 /9.6v light made from aluminum, so I can use my nice 7.2/9.6/12/14.4v smart-charger and nice, standardized battery-packs.

Get/make 2 versions, one direct-drive, and one with a smart-controller for variable brightness, etc.

Daniel Ramsey · Sep 22, 2002

That sounds like a good stable modding platform for the 5 watter, good luck with it!
seriously it was my choice other than the milled protype in mind. I was working on just an illuminator head assembly only with a finned ventilated heatsink backed by an epoxy/ground silica mix that uses also some copper I got through washing some Permatex copper anti-sieze through an acetone bath. Its being mixed with some thermal epoxy I picked up earlier this year for my other luxeon mods. The illuminator head will attach to a li-ion battery pack I salvaged from an old laptop. The silica is basically whats used for bead blasting and according to my tests its a very ablative heat sink, similar to what the space shuttle uses. Course its possible to fuse this with an oxy-acetylene torch but then I might be getting ahead of myself here, after all I do enjoy some secrecy.....

ElektroLumens · Sep 22, 2002

Originally posted by Pi_314:
Any guess as to how long a 5 watt LED could run on a 9V battery?

Another question...I just bought a dremel tool...It's the new rechargable. I noticed the battery after buying it ....that it's 7.2 volts.
See any problems using that battery?

Using this battery sounds like a good idea.

Wayne J.
www.elektrolumens.com

ElektroLumens · Sep 22, 2002

Originally posted by Daniel Ramsey:
That sounds like a good stable modding platform for the 5 watter, good luck with it!
seriously it was my choice other than the milled protype in mind. I was working on just an illuminator head assembly only with a finned ventilated heatsink backed by an epoxy/ground silica mix that uses also some copper I got through washing some Permatex copper anti-sieze through an acetone bath. Its being mixed with some thermal epoxy I picked up earlier this year for my other luxeon mods. The illuminator head will attach to a li-ion battery pack I salvaged from an old laptop. The silica is basically whats used for bead blasting and according to my tests its a very ablative heat sink, similar to what the space shuttle uses. Course its possible to fuse this with an oxy-acetylene torch but then I might be getting ahead of myself here, after all I do enjoy some secrecy.....

Hey Daniel,

Sounds like you have some great idea!

Wayne J.
www.elektrolumens.com

hotfoot · Sep 22, 2002

Originally posted by ElektroLumens:

Originally posted by Pi_314:
[qb]Any guess as to how long a 5 watt LED could run on a 9V battery?

Click to expand...

Hmmm... assuming a full constant 5W draw, the poor little alkaline 595mAh 9V will poop out after around 8+ minutes.

5 watt Luxeon Star Testing, Runtimes, Brightness, ETC.

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