Brinkmann 3AA - LS/o Mod

I just wrapped up building a "Luxeon pill" that drops into a Brinkmann AA flashlight. I chose the 3AA body because I wanted to direct drive the Luxeon off of 3 Ni-Mh batteries to get 3 x 1.2v = 3.6v I like the efficiency of direct drive plus I don't possess the electronic genius that some of the other guys here do.

I chose to build a pure copper heatsink which was bonded using Arctic silver thermal expoxy to the original LS/o aluminum heatsink. Using the copper also allowed me to solder on to pick my negative lead. I built a center post from some non-conductive washers with a center stud to route the positive lead.

I can't begin to say how ecstatic I am about how this sucker blasts light !! Comparing it to an INOVA X5 if was hard to tell the INOVA was even on! My Lightwave 3000 didn't fare any better.. Starting with the Ni-Mh's I'm getting the following results:

* Freshly charged-
4.05 volts
1.120 amps

* 10 minutes run-
3.74 volts
980 MAh

*15 to 20 minutes run-
3.67 volts
850 MAh

Did I mention this thing is bright? darn near "permanant eye damage" bright.. I'm also extremely impressed with the thermal stability of this flashlight so far, even though I haven't conducted any continous run-time tests. I'm convinced the copper is responsible for this since even when the flashlight head becomes warm, removing the pill I find that the temperature appears to be lower than that of the surrounding metal. The above readings are stated at approximatly 10 to 12 seconds run where the readings stabilize cleanly. Testing with alkalines will happen (4.5v) but I intend to build up to that slowly, as I'd just hate to fry a creation that took so many hours to build.

So does any one know if a well heatsinked Luxeon will survive 1.5 amps @ 4.5+ volts??

With the freshly charged Mi-Mh's, I found that consumption began at 930 MAh and climbed steadily to 1.15 amps before "settling". I plan to use the Ni-Mh's for their rechargabilty, but would like to dertermine If I can get away with the alkalines (extra power) without taking a big chance that I'll fry it..

I might also add that inspiration for this mod came from a combination of Lambda's work with his Brinkmann "Illuminator" + Electrolumen's work on the "Blaster" Mag along with some collaborative conversation w/Mr. Bulk. Thanks to you guys (and the many others) who take the time to share with all of us.

About the only decent "measuring device" I have is my Wavetek DVOM that handles up to 10amps. I don't have any lightmeter or temperature probes. In fact, I test temp differences my holding the component up to my lip (so nothing is very hot for sure and I don't get numbers).

I'm hoping that overdriving like this doesn't result in a degradation of light output of the Luxeon but I am willing to accept that I'm shortening it's overall life..

I certainly ageee with your statement that individual Luxeons perform differently. I have come to accept that as "life on the bleeding edge"

Nice Mod!

Can you post pics of the copper pill?

The Luxeon, as Elecktrolume has proven, can take 1.5A when properly heatsinked. The only problems you may see with this mod would be related to the small AA case. A Mag 2D has a lot more aluminum to absorb the heat.

My estimations for power dissipation, based on how hot things get, is that a 2AA Brinkmann can safely handle ~2.5W continuously. The 3AA probably a little more, say ~3W.

So, if you use alkiline cells, just keep a check on the temps and see how it goes.

The "lip" method for temp measurement works quite well, that's all I ever used until I splurged and bought a TPI infared therm just to double check things. But if it won't burn your lip, the Luxeon most likely is not getting too hot.

For comparison, the Ultra Illuminator (Ledgend LX case) will push 2Amps with fresh batteries (~6.8W), and settles down to ~1.6A (~5.4W) for most of it's run. It does however, get very hot after 5-10 min and will start to enter self protect mode (strobing) to limit the Luxeon temps below 100C (212F).

Do keep in mind, Luxeons vary in voltage drop, so one can run hotter than another.

Just a rule of thumb, when I measure 110F on the case of an Illuminator that's been running for 1/2 hour, the Luxeon temp will register ~125-130F inside. So, the thermal resistance from Luxeon to case will dictate how hot it gets inside.

Just use your common sense, check temps, and remember that 1.5A in a small light is a lot of power!

Again, nice mod!

I plan to visit a friend that has a digital camera sometime during the next week or so, I'll get some pix of the finished pill and also the various raw parts I used to assemble it.

I made the copper heatsink from a piece of copper plate that I found at a metals surplus store. It's about 1/16 inch thick.

I simply make a slug (a little smaller than a dime) that matches the diameter of the ground down Luxeon. The slug sinks heat so effectively that I have to use a torch to heat it up to add the "solder dot" for the ground pickup. Not even my 95watt iron could do it right. Then I epoxy them together and use the columator as a clamp to keep them lined up. At three minutes, I take it out and peel off the excess epoxy while it's still possible, then put it back together to fully cure.

I have transferred this pill between both a 2AA and 3AA. In 2AA mode I use lithiums and it still makes more light than either my INOVA X5 or Lightwave 3000 ! It's only pulling 390 MAh like this so I think this about one of the best mods there is to build.

One additional thing I'd like to point out for anyone attempting this mod is that not all Brinkmann AA flashlight heads have the same internal dimentions. In the 3.6 million serial range, the heatsink is about the size of a dime. In the 4.7 mil range, heat sink will be about the size of a nickle since they machine more material out of the head. I don't know exactly when this manufacturing change occurred.

The only problem I have encountered with this mod so far, is that now ALL of the other LED flashlights in my collection are dissapointingly dim by comparison. I may have to have a "fire sale"..

Thanks for your good words & advice Kevin, it's much appreciated.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Slick:
[QB]
One additional thing I'd like to point out for anyone attempting this mod is that not all Brinkmann AA flashlight heads have the same internal dimentions. In the 3.6 million serial range, the heatsink is about the size of a dime. In the 4.7 mil range, heat sink will be about the size of a nickle since they machine more material out of the head. I don't know exactly when this manufacturing change occurred.[QB]<HR></BLOCKQUOTE>

And everybody thinks putting Illuminators together is easy. Yes, many other variations in their demensions also. It's just something you have to deal with for each mod. Not a production line type assembly since you can't control all the dementions of the flashlight.

But, with a little TLC, great mods are possible.......

Sounds like a winner Slick!Great mod!

I was planning on doing something similar in the near future,and if you don't mind,you have given me some ideas.I have done Brinkmann mods w/a boost circuit before,and since a direct-drive takes up less room in the barrel,how about making a multi-finned heat sink to help compensate for the extra heat.I'm thinking of using two different sized slugs,alternating larger and smaller slugs to form fins w/a hole down the center to run anode connection wire.Will this work?
Has anyone tried a multi-finned heat sink yet?Now that I think about it,the fins wouldn't make a difference(no air flow),but the extra mass should help.

I looked around through many bins of computer heatsinks of all kinds but pretty much believe that you need "airflow" around those fins to makem' work.. so I scrapped that approach.

I finally decided that I like the thermal conductivity that pure copper offers. A nice chunk that makes lots of contact to the surounding aluminum body will pull heat away amazingly fast.

I need to invest in one of those irfrared temp sensors & light meter of some sort.. This is starting to add up!

Slick,

I use computer CPU heatsink hacked to 4 small pieces. The light has hi and low switches. http://photos.yahoo.com/pilgrim1956

The hi has no resistor, it gets all the juice. The low is about 80mA, works really well. I use it every night. It can stan up as well.

Henry

If you can get your hands on one of the new 5 watt luxeons try it in the 3 AA legend with 5 "N" cells, run time may be short but its something to try for an easy mod without a boost circuit.

I have found that copper washers available at hardware stores are effective, and easy to find in the correct size.

When I did my Brinkmann 3AA LS mod, I used a LOT of copper:
http://www.hunting-pictures.com/members/jimdillus3/index.html

The problem I encountered is with the optics. The LS collimator lense is too thick to fit in my light with all that copper heat sinking.

How did you mount your optics in the light?

Hey Slick, nice mod. Been busy trying to sell stuff and finish up my own mod (finally) but I do like the Pill idea as I told you over the phone the other day. Mine gets good and warm on the outside real fast, so I know the heatsinking is working, but it would be nice to just drop in a Pill with any metal flashlight we find:
http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=14&t=000278

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Avatar:
I have found that copper washers available at hardware stores are effective, and easy to find in the correct size.

When I did my Brinkmann 3AA LS mod, I used a LOT of copper:
http://www.hunting-pictures.com/members/jimdillus3/index.html

The problem I encountered is with the optics. The LS collimator lense is too thick to fit in my light with all that copper heat sinking.

How did you mount your optics in the light?<HR></BLOCKQUOTE>

I considered using copper washers but was afraid that having a hole in the center (right where the LS is) would not be a good idea. Consequently I'm using a single solid copper disk (beneath the original aluminum one) so I still have plenty of verticle space left.

When I mounted the optics I chose not to use the original lens (as a cover). The Luxeon collumator has a groove around the leading edge that locates it centrally in the bezel. I use an "R13" size O-ring behind the collumator to keep it firmly located once the bezel is screwed down. When I get the photos shot, I'll take some of the collumator + spacer too..

I haven't run mine up on alkalines yet - just Ni-Mh's. I'm taking a fairly slow approach to testing to be certain that I have adequate heatsinking before I give it "full throttle". It seems to be doing really well so far. When the thing heats up, I've checked the internals and they're not getting any warming than any thing else on the light.

Of the several dozen Brinkmann Legend AA Luxeon mods I have made up and sold locally back in january a simple dime is a neat heatsink.
On the other hand aluminum does transfer heat better.

Heat transfer between aluminum and copper given good surface area contact is easily sufficient to allow copper washer to be used. The 'hole' makes little or no difference. The aluminum transfers heat away from the LS and the copper accumulates quite a bit of heat given its relative mass. Then more heat is transfered to the aluminum flashlight housing.

I have had my Death Star mod on for over two hours on a single set of batteries. It is still VERY bright.

I have had it on for over 1 hour continuously, and the temperature can only be described as 'warm'. It was in no way hot.

Hay Slick (just got back in), I think Avatar may have something there with the copper washers, especially used in your configuration where you keep the original heatsink anyway. I can't use the washers in my version since the hole is right where I would epoxy the LS...

Unfortunately, I still couldn't use a washer for my design since my "pill" uses a lead that is soldered directly to the center of the copper heatsink. Then epoxied together fiber washers fit over that and build the post for the positive lead. I may have to look into the hole saw idea that Lambda mentioned - but only if I decide to produce some of these for sale.

Avatar - thanks for the info on your run tests. By any chance, did you happen to measure the current consumption of your flashlight during your tests?

Hey,

I was just checking out this thread. Very good info here.

I just did a mod with the Brinkmann 3 AA I had laying around for a while. I used a 3/4" drill bit in my drill press, and machined out the inside of the head. Then I epoxied on the new Lambertian Luxeon Star onto a small aluminum heat sink, the size of the newly enlarge head inside. I drill a couple of holes for the wires to pass through, put the wires through and soldered them onto the LS. Then I epoxied around the wire connectcions so they cannot move or be damaged from tweaking. I pushed this into the head tightly, and epoxied it in with heat sink epoxy that I mix up custom. When You do it this way, the collimator will fit in the head just fine. No need for the clear lens. If you space it properly, the collimator fits in snug, and focuses properly. This is the Brinkmann 3 AA I have up for auction on eBay right now.

Here is a photo of the machined head inside, with the Lambertian Luxeon Star mounted. I place the collimator in the head cap, and screw it in for a nice tight, water resistant fit (using the lens o-ring still).



I did this direct drive, so it is best to use rechargables. It gets fairly warm with alkalines. Don't know if it can take them or not.

Wayne www.elektrolumens.com

Sorry, no luck with power consumption. I tried but my 30 year old multi-meter was not accurate. My new multi-meter is no where to be found.

It is direct-drive with alkaline batteries. I have had no problems. The key to keeping things from overheating is the heat sinking. Not only do you need plenty of surface area for heat transfer, but you need a decent amount of mass for the heat sink.

Keeping the light on continuously for 1 hour was an abusive test for any light. Especially for the Death Star, which has a purpose exclusively of identifying targets at night.

If you check out the web page I linked to in my first post on this thread, you will see just how many copper washers I used.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Avatar:
If you check out the web page I linked to in my first post on this thread, you will see just how many copper washers I used.<HR></BLOCKQUOTE>

Yeah, I saw that you had a half dozen of 'em in there That ought to do the job quite nicely. From the looks of your washers and the Luxeon you used, I'd say your light is one of the "large diameter" machined heads. 2 of my are large and the other 2 are small (dime sized).

I'm looking into getting an infrared thermometer so I can compare which of the 2 designs sinks heat better..

My Brinkmann 2AA LI is ~158mm/6.25" long, just OK for EDC.

How long is the 3AA?