Streamlight 4AA led HEAT!

tygger

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i just recieved a streamlight 4AA led from brightguy.com. the light is very bright and durable and has a nice touch with the pressure release valve. the only problem is that it gets really warm, too warm, after its left on for 5 min. or more. i know i could use 3 lithiums with a dummy cell, etc. but i really don't want to do that cause alkalines are really cheap and i will use the light every day. are the leds being driven way too hard? how long before the they start to degrade? did i get an early model without added resisors? i need to find out so the light doesn't quit on me when i really need it.
 

llvo

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Hi, I got this problem, too.
I left it on for about 20mins and the heat melt the surface of the reflector and streamlight sent me a replacement with 22ohm resistors, it still gets warm that I have to switch it off for fear of damaging it again.

It seems that not all 4AA owners have this problem /ubbthreads/images/graemlins/rolleyes.gif
*(you can search for the old discussions since there are several posts regarding this matter)
 

tygger

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thanks for the info. i checked the previous posts and this seems to be a fairly common issue. does anyone know if streamlight is planning an improvement? possibly added resistors?
 

shankus

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I wouldn't say that it is common. Yours is the 2nd or 3rd light I've heard of with the problem.

Mine runs with less current when running on NiMH cells. Perhaps it would run in an acceptable temp range for you with the decreased current.
 

steve_vance

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I just spoke with the manager of Streamlight customer service....I emailed her both of the threads that have addressed this; she is having engineering get back to me on this. Soon I hope that we will have a definitive answer to this question.
One thing to note: how the light is packaged (box or blisterpack) does not in any way indicate its model, or which production run it is. Streamlights have always been available to distributors two ways: blister packed or boxed.
I will post as soon as Streamlight responds.
/ubbthreads/images/graemlins/grin.gif
 

StuU

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Somebody is mixed up here. You don't have to use LITHIUM batts when doing the 3 cells + dummy cell. I have been using 3 ALKALINE cells + dummy cell in my SL7 for the last 6 months. It works great. Lots of light. Long battery life- I'm on my second battery set in 6 months at this point. Lithiums would make the light marginally brighter but are not necessary.
 

asdalton

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The reason that many people use three lithium AA batteries is to achieve flat discharge, resistance to cold, and light weight. Don't use four Li batteries, though. Four NiMH batteries are safe, in my experience.
 

pilot4x4

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I had the same problem with a light I bought a month ago. It had the 22 ohm resistors in it. I put the Energizers in it that it was packed with in the blister pack, then we took a night walked and ran the light for 35 or 40 minutes. When I returned I noticed an odor coming from the light. It was the adhesive that holds the reflector assembly to the piece with the battery contacts. That adhesive was melting and the reflector was slightly distorted. I spoke with two people at Streamlight and they said they'd never heard of any problems. I guess I talked to the wrong people. I sure hope they can come up with a fix for the problem because it's a nice light but right now you can't count on it for long periods of continuous use. John
 

The_LED_Museum

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I've got one of these, but I don't know exactly where it is at the moment. If I remember right, it has 22 ohm resistors (red-red-black-gold I think) inside the head, and nothing on the bottom of the head. Ahhh, there it is...right where I left it except it's lying on its side instead of standing upright. Most of the LEDs do have a slight blue color, but not that "pissed off turquoise color" that a severely overdriven white LED would produce. I'll have to turn mine on and leave it on and see if it starts to smell funny after 20 or 30 minutes.
 

llvo

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I left the light switched on for over one hour last night.

Here's the result:
The SL 4AA LED *new version with 22ohm resistors* will get warm but will not get damaged at all after one hour. But you can smell that 'hot smell'??

It was powered by 4 freshly charged NiMH batteries.
Very bright for 7LED! Overall brightness is equal to my Surefire KL1.
 

pilot4x4

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I've run mine with NIMH and it doesn't seem to get as hot as it does on Alkaline and it's not noticablly dim compared to the alkalines. On a set of 2100 mahs I can only run it about two hours before it's getting dark enough that it needs a fresh set. John
 

Quickbeam

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Just FYI, at 22 ohms resistance at 6v, each LED should be drawing about 110mA. Very overdriven! Throw in a dummy cell for 4.5v and they'll be drawing between 40mA and 45mA - much more reasonable, but much dimmer as well.

If your 4AA has 12 ohm resistors on each LED (first production run) and no supplimental resistor, at 4.5v (one dummy cell replacing one alkaline) the LEDs are drawing around 80mA to 85mA. This probably gives really good light but doesn't create too much heat. However, at 6v (4 alkalines) the're trying to draw around 200mA!!! No wonder the first ones out cooked the reflectors!

Now remember, factory specs (which we all ignore) for the Nichia white LED is 20mA at 3.6v...

FWIW:

with 22 ohm resistors, 4 alkalines, 150 lux at beam center at one meter
with 22 ohm resistors, 3 alkalines, 88 lux at beam center at one meter.

I'd bet that with 4 alkalines, resistance of around 30-40 ohms on each LED would be a reasonable compromise between heat and output...
 

steve_vance

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hey folks....I got the answer from Streamlight's engineering dept. Here it is:(it's from Jean, my internal contact at Streamlight; as you all probably guessed, I am a Streamlight distributor, but I do not sell anything retail) /ubbthreads/images/graemlins/grin.gif
Hope this is helpful:

Sorry Steven,
Here is some additional information that I just received and thought you may be interested in. Let me know if there is anything additional.
Jeanne

4AA LED RESISTOR REVISIONS

The first units had 12 ohm resistors in series with the LEDs (7 resistors, one for each LED). The 12 ohm resistors, visible through theopening in the side, are color coded BROWN, RED, BLACK, GOLD.

There was then an interim fix which added a large one ohm resistor to the back of the housing.

The current production assemblies do not have the external resistor and the internal ones have been changed to 22 ohms. These are color coded RED, RED, BLACK, GOLD.

You can probably identify which assembly you have by looking at the color codes on the resistors through the openings in the side of the module. All resistors will be the same value. Unfortunately there isn't a whole lot of visible difference between the shade of brown used in the old ones and the new red, so you need to take a really good look.

There is little to no apparent difference in intensity of any of the three versions. LEDs unfortunately have a very large range in the amount of current they draw as part of their normal manufacturing process, and the original values were chosen using LEDs of the lower current end of the range. This caused the ones that drew higher current to be driven too hard. They not only were failing because of heat, but were no brighter than ones operating correctly.

If operated continuously, it is normal for the 4AA LED to get warmer than the Xenon version when the batteries are fresh. If operated continuously with new batteries, the plating in the center of the resistor may discolor and crack or blister. This is normal and does not affect the light output.

.........................................................................................

Just a reminder that ALL Streamlight products are covered by a lifetime warranty; if you have one that is not performing properly, send it back to Streamlight. Their address is:
Streamlight
Attn: Repairs/Warranty dept
30 Eagleville Rd
Eagleville, Pa 19403
 

Lagged2Death

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[ QUOTE ]
Quickbeam said:
Just FYI, at 22 ohms resistance at 6v, each LED should be drawing about 110mA. Very overdriven! Throw in a dummy cell for 4.5v and they'll be drawing between 40mA and 45mA - much more reasonable, but much dimmer as well.

[/ QUOTE ]

It would be interesting to see a run-time chart of the 3 cell + dummy cell arrangement. A 60% drop in current sounds like a recipe for a slower drain and longer runtime - or am I being naive?

I know my SL 4AA LED produces a lot less light with a tired set of batteries, but it's still a very useful flood of pleasingly white light. It would be nifty to have the option of reduced output and extended run-time, while saving a few cents on batteries to boot.

Is there a good place to buy a solidly-made dummy cell, or is that something a True Flashaholic(TM) would build on his own?
 

asdalton

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[ QUOTE ]
Quickbeam said:
Just FYI, at 22 ohms resistance at 6v, each LED should be drawing about 110mA. Very overdriven! Throw in a dummy cell for 4.5v and they'll be drawing between 40mA and 45mA - much more reasonable, but much dimmer as well.


[/ QUOTE ]

If you account for the internal resistance of the batteries, then the new model draws about 90 mA per LED (with fresh alkaline batteries). That's high, but not quite as bad as 110 mA.
 

eluminator

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Using NiMH cells will reduce the power delivered to the LEDs a little bit. At least it does in my original 12 ohm light where the current per LED dropped from 90 ma to 71 ma when I went from alkaline to NiMH. These readings were when the LED's were cold. As they warmed up, the current went up too.

I'm wondering how the Nichias are holding up under the strain. To my knowledge, nobody has reported any LED damage. But if the light output is diminishing with use, it might be hard to detect unless measurements are taken.

I make dummy batteries out of whatever I can find that has the right diameter. My current favorite is to use the white fiberglass reinforced rubber hose 1/2 inch in diameter that is sold wherever plumbing is sold. It's used to connect wash basins, etc. to the pipes coming through the wall. Kind of expensive because it has brass fittings on the ends, but if you want the Rolls Royce of dummy batteries, this may be it.

I cut it a little shorter than an AA cell. Jam a small rubber grommet in each end. Cut a length of 3/16 diameter copper tubing (or small diameter brass rod etc.) the length of an AA cell, and shove it through the grommets.

The rubber hose has a slightly smaller diameter than AA cells. If you want a snug fit, wrap with vinyl electrical tape.

Voila, dummy batteries for dummies.
 

shankus

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I measured mine at just under 83 mA per LED on fresh alkalines. On fresh NiMH, it was lower. I posted it here somewhere.

My reflector has never discolored, but then, I painted mine gloss white a few weeks ago. It got rid of the spirograph-like artifacts in the flood.

CCrane has dummy AA cells, I bought some from a CPFer in B/S/T. If you post that you want to buy some, I'm sure someone will respond. On CCrane, you can only buy them 10 for $10.

A word of note about the CCrane AA dummies: I measured mine at 1 full OHM. I had to file the plating off of both ends, to bare metal. After that, the meter floated between 0.1-0.2 OHMs.


*EDIT* Here is my original thread:
Do you use NiMH in your Streamlight 4AA LED? *EDIT*
 

Quickbeam

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I use the CCrane dummy cells... /ubbthreads/images/graemlins/smile.gif I'm surprised they still have them in stock! I don't know if it's still in effect, but there was no shipping charge when I ordered.
 
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