# brightest 5mm leds without a metal heatsink?



## mpteach (Oct 18, 2009)

What is the brightest 5mm leds without a metal heatsink? How many lumens could i expect?

Im adding some lighting to my new o1maxima flipkey/remote.
https://www.candlepowerforums.com/threads/245521

I might be able to have a new bottom case machined out of aluminum but i dont think im going to do that. I could just drill two holes in teh plastic and place dual 5mm leds on the front right side, remove the spacer below the remote guts and fit 2 x 2450 primary coincells, or rechargables or maybe a lipo instead.

I dont like how my lighthound 2x2016 5mm coincell fauxton light shines light backwards into my eyes.


----------



## qwertyydude (Oct 19, 2009)

I'd have to say the Nichias like in the Fenix E01. Expect about 10 lumens.


----------



## [email protected] (Oct 19, 2009)

The stuff Fred uses it the killer aaa.


----------



## TorchBoy (Oct 19, 2009)

An unmounted XP-G is about 4.9 mm across the diagonal... :devil:


----------



## mpteach (Oct 19, 2009)

TorchBoy said:


> An unmounted XP-G is about 4.9 mm across the diagonal... :devil:



about??? about? wheres the +- manafacturing tolerances and the ambient temperature and presure you measured it at.....

the fenix does have heatsinking.

so two 5mm will give me 20L total continously?

How is the tint on that nichia?


----------



## JohnR66 (Oct 19, 2009)

Funny isn't it? A XP-G/XP-E package is smaller than a 5mm LED. They are so small with such a tiny surface area that they might need heat sinking when driven over only 30ma.

For the OP, I'd seek out the Nichia GS 5mm LED. Problem is availability. The Energizer keychain squeeze light has the GS in it if you can find that. ($3 at Target). These seem to be a cooler tint (b bin?). The c bin is overall a warmer "cool" white. The GS is the brightest 5mm LED I know of, but it has an angry blue center to the beam.

I have a few GS LEDs by recovering the LED from the light when the batteries run down. It costs more to buy new batteries for it than just to get a new one. If I need A76 batteries, I'll just buy the light and remove the batteries because a 3 pack of batteries is almost $6.


----------



## mpteach (Oct 19, 2009)

I could put a strip of metal down the the right side to spread the heat over a larger part of the plastic case which would help some.

I dont mind if the light is a little bit blue i just dont want it very noticeably blue.

whats the ratio of ma to lumens?


----------



## [email protected] (Oct 19, 2009)

5mm leds are measured by cmd. And Nichia gs is vaguly 40000.


----------



## Grumpy (Oct 19, 2009)

I have some of the highest bin GS leds if you want a couple for your project for free. Just send me your email address and I'll mail them to you at no charge.
If anyone else wants some for a project let me know what you will be using them in and I might give you some as well for a small project. I think I have less than 20 left. I would like to see the completed project.


----------



## TorchBoy (Oct 19, 2009)

[email protected] said:


> 5mm leds are measured by cmd. And Nichia gs is vaguly 40000.


mcd, for millicandela. http://led.linear1.org/lumen.wiz is a tool to convert from mcd to lumens.

mpteach: 3.45 mm x 3.45 mm +/- 0.13 mm.


----------



## mpteach (Oct 19, 2009)

[email protected] said:


> 5mm leds are measured by cmd. And Nichia gs is vaguly 40000.



doesnt cmd depend on viewing angle? What is the viewing angle of the lighthound fauxton? that angle is acceptable, except for the small fraction that backsatters to my eyes.

Im thinking about doing this project as fast as possible so im going to build it the easiest way with available parts. I can always swap a nicer tinted bin led or upgrade the batteries later or maybe even go crazy and have the case machined from aluminum and put a xp-g in there, but i shouldnt wait longer now.

Im thinking about using 2x2450. I dont know if that would burn up the dual leds direct drive since those can push alot more current than 2016. Actually is there a small regulator that would be good to use?

Im also considering li-ions coin cells which would give me a flater discharge curve or even 1 or 2 thin lipo packs.

What kind of voltages/current do i run these nichias at??

As far as the UI im only intersted in pushing a button for it to go on and pushing it again to go off, either a mechanical clicky or an electronic button like the fauxton. I dont need momentary on either.


----------



## mpteach (Oct 19, 2009)

Er

Thanks grumpy pm sent

yea its mcd not cmd

What is the viewing angle of those GS? I'll take them anways im just curious.


----------



## Neondiod (Oct 20, 2009)

There are 5mm leds that can be driven at 70 mA like this one: http://www.lck-led.com/p528/5mm-Powered-White-LEDs-13Lumen--10PCS/product_info.html
They claim they put out 13 lumen. The big legs removes heat.

Br


----------



## Cemoi (Oct 20, 2009)

Neondiod said:


> http://www.lck-led.com/


Thanks for the link, I didn't know this seller.
Prices are rather low, and so are the shipping charges (about $2 to Europe or the US) and they have high flux bin LEDs.
Unfortunately they only specify the flux bin, not the color bin.


----------



## mpteach (Oct 26, 2009)

What voltage do those nichia GS run at? will 2x2450 burn out dual gs? IF so is there a very small regulator available? Would a lithium polymer battery provide the correct voltage? \

I dont like when lights are intially bright and rapidly dim.


----------



## JohnR66 (Oct 26, 2009)

The GS at 20ma is around 3.18v
At 30ma it is 3.26v
Don't know about the batteries.

At 40ma I did not notice fading after 192 hours of continuous operation.
They probably can handle 50ma with good heat sinking of the leads (especially the cathode). Nichia uses a copper lead frame which helps. Most 5mm LEDs have tinned steel leads.


----------



## TorchBoy (Oct 26, 2009)

JohnR66 said:


> Nichia uses a copper lead frame which helps. Most 5mm LEDs have tinned steel leads.


That's interesting.

I came across http://www.besthongkong.com/product_info.php?products_id=526 while checking out their LED drivers a day or two ago. They claim 20 lm.


----------



## mpteach (Oct 27, 2009)

How can i tell if the led is starting to overheat?

The coincell datasheets that ive found are useless, they only cover really low current discharges.

I believe im going to use a LiPo pack anyways.


----------



## JohnR66 (Oct 27, 2009)

TorchBoy said:


> That's interesting.
> 
> I came across http://www.besthongkong.com/product_info.php?products_id=526 while checking out their LED drivers a day or two ago. They claim 20 lm.



I was looking at their 5mm 18cd "low degradation" white LEDs. They want $40 something for ten of them! Who do they think they are? Radio Shack?

I can get Cree XPEs for around that.


----------



## jtr1962 (Oct 27, 2009)

JohnR66 said:


> I was looking at their 5mm 18cd "low degradation" white LEDs. They want $40 something for ten of them! Who do they think they are? Radio Shack?


Link

Actually each "item" here is 10 pieces, so that's 100 pieces for $40.90. Still a little high IMO, but not bad.

If the specs are correct, then these achieve ~70 lm/W at 20 mA. Pretty decent although obviously not as good as the best power LEDs.


----------



## JohnR66 (Oct 27, 2009)

Phew, that's better: 10 pcs=1 unit.

I might try some of them as some of the better ebay 5mm LEDs are around 30 cents each and all that I have tried fades too quickly to be of any real use. I just purchased some from JELEDHK. They are the 55cd ones. They are different from the older ones that had the angry blue center. The newer ones have less of a bluish center to the beam and are less bright. After 300 hours at 30ma they became very dim.

These may be worth it if they hold up.


----------



## TorchBoy (Oct 27, 2009)

Ah, reminds me of the good old days, when I'd put 6 white 5mm LEDs in a key ring torch and spend about the same on them as a Cree MC-E costs now.

The fading issue really is a bit of a problem. I fixed the light in my father's radio about three times with two or three 5mm LEDs each time, but each time after about a month they had faded so much they were next to useless. I gave up and put in an XR-E running a small current and it's going just fine almost half a year later.


----------



## mpteach (Oct 27, 2009)

The Leds will partially be in the plastic case and placed side by side, but i can solder the cathode leads to a 2.5" long copper strip placed in the right side of the plastic case to spread the heat a little better. Should i go 50ma? or only 40ma? Is there an easy way to tell I'm overdoing it before the Leds get damaged?

If i use a resistor and direct drive with the LiPo how fast will the brightness drop? When the battery is 50% discharged how much dimmer will the nichias be?

If it dims badly i could run the Leds in PWM, or with a Buck or LDO regulator instead of direct drive. The efficiency wont be much different between those three methods right?. Which of them would be the cheapest? And small. And something i can order that doesn't take a month to get lol.


----------



## JohnR66 (Oct 28, 2009)

You can probably get away with 50ma using the Nichia GS, but that is starting to push things in the 5mm realm. At 40ma the longevity of them is not an issue nor is heat. Their high conversion efficiency means less heat produced as compared to other 5mm LEDs. The discharge voltage curve for most rechargeables is fairly flat that I would not worry about a special driver for such a basic application.


----------



## JohnR66 (Oct 28, 2009)

TorchBoy said:


> Ah, reminds me of the good old days, when I'd put 6 white 5mm LEDs in a key ring torch and spend about the same on them as a Cree MC-E costs now.
> 
> The fading issue really is a bit of a problem. I fixed the light in my father's radio about three times with two or three 5mm LEDs each time, but each time after about a month they had faded so much they were next to useless. I gave up and put in an XR-E running a small current and it's going just fine almost half a year later.



There are a few good 5mm LEDs around. Ebay is just not the place to look for them.:laughing: Power LEDs are great, but low power LEDs are fine where less light and lower cost is needed.

Now that I have a light meter, I am retesting seven of the better LEDs I have. I will have results posted in about a week. Note that no ebay LEDs have made it to this stage in testing except for a couple flux versions.


----------



## mpteach (Oct 28, 2009)

The lipo starts at 4.2v or 4.1v and goes down at an even rate till its almost dead at 3.6v that a .6 or .5v drop, halfway a .3v drop. Woudlnt that be noticeable with an led? A regulator should give me the same level the whole time. If it would be too hard or expensive i could live with that and just recharge it more often.


----------



## TorchBoy (Oct 28, 2009)

JohnR66 said:


> There are a few good 5mm LEDs around. Ebay is just not the place to look for them.:laughing: Power LEDs are great, but low power LEDs are fine where less light and lower cost is needed.


Well, I found that even non-Ebay low power LEDs aren't fine running at 20 mA for that many hours a day. They came from two or three different sources, but I'd bet none were Nichia or other reliable brands. The Cree XR-E produces a more even backlighting, too.


----------



## TorchBoy (Oct 28, 2009)

mpteach said:


> The lipo starts at 4.2v or 4.1v and goes down at an even rate till its almost dead at 3.6v that a .6 or .5v drop, halfway a .3v drop. Woudlnt that be noticeable with an led?


With a resistor dropping excess voltage then you might not notice much drop in intensity. I've found it tends to get masked by the lack of colour change. LEDs don't go brown when they get dim. The more voltage gets dropped across the resistor the more stable the LED's intensity will be, but it's probably not worth specifically going for low Vf LEDs.


----------



## mpteach (Oct 29, 2009)

How many ma does the gs need to be just bright enough to locate at night like a tritium vial?


----------



## JohnR66 (Oct 29, 2009)

I tested one to light bright enough at 90 microamps.

LEDs don't always light reliably in this range as small conducting channels seem to form in the die due to ESD or normal use. You must handle them with care if you plan to run them at micro amp currents and expect them always to light. Generally not much of an issue with quality LEDs, but it is something to look out for. Use a grounded wrist strap and grounded soldering iron when working with them.


----------



## mpteach (Oct 30, 2009)

Possible change of plans
Im attaching my housekey to the bottom(it will swivel) so i dont need that ring on the back.
I have a space 25mmx10mm and 6mm deep on the back now. On the front right i have 10mmx10mm and 12mm deep that shares space with a 3mm transponder chip.

I could run the 600mah Lipo at 250ma and still get 2hrs runtime.
Im thinking about 2 options

1.The case plastic is 2mm thick. I could line the inside back, left, right, and the bottom with a thin copper sheet, that would total 20cm^2 of area(as long as there are no rf issues w the remote then id have to do less) and then fit a power led in the front space and a clickie switch and charging jack on the back.

2. I could put say 5x 5mm leds across the back, the switch on front right top where i prefer, and the jack on right front.


If i did the first option with the power led, would i have room enough room to fit it? Would the beam angle be too wide? How would i attach a window to cover it?
Note: The top and bottom half of the case seperate when opening so i couldnt glue it to both halfs.


----------



## mpteach (Oct 30, 2009)

I wont be able to test if metal below the remote board doesnt effect its range for another week. 
Apparently theres two different 01 maxima remotes with different fcc numbers/frequencies. The board and position of the battery are different.The ebay flip key's molded battery holder is designed for the other remote. Im going to exchange the boards. I have to mod the molded 2025 battery holder to make space for the lipos anyways.

So much for fast lol


----------



## TorchBoy (Oct 30, 2009)

mpteach said:


> I have a space 25mmx10mm and 6mm deep on the back now. On the front right i have 10mmx10mm and 12mm deep that shares space with a 3mm transponder chip.


Shove an XP-G on a 10 mm square board in there with a 10 mm optic and be done with it.


----------



## mpteach (Oct 30, 2009)

TorchBoy said:


> Shove an XP-G on a 10 mm square board in there with a 10 mm optic and be done with it.



I would like to do that! How deep would the xp-g + optic be?
How many cm^2 of of copper would i need minimum to spread the heat over enough plastic case to not melt the led @ 250ma?

It might be difficult to fit the xp-g and transponder chip in there. I have to keep the transponder in the front next to the key for the ignition to read it.


----------



## jtr1962 (Oct 30, 2009)

mpteach said:


> How many cm^2 of of copper would i need minimum to spread the heat over enough plastic case to not melt the led @ 250ma?


An XP-G @ 250 mA only makes about 0.42 watts of waste heat. The 10mm board should be sufficient to dissipate that without much temperature rise.


----------



## mpteach (Oct 30, 2009)

jtr1962 said:


> An XP-G @ 250 mA only makes about 0.42 watts of waste heat. The 10mm board should be sufficient to dissipate that without much temperature rise.



Its surrounded by plastic and battery it not in open air. If heat's not an issue than i could increase the ma  The 600mah lipo can put out 600ma. Maybe i should have a high low and mode. If i had just one then i think 300mah would be a good compromise between brightness and runtime.

xp-g @ 300ma is only 2.9v. Maybe a regulator makes sense.


----------



## jtr1962 (Oct 30, 2009)

Here's a chart of the XP-G power consumption and waste heat. Red line is power consumption and white line is waste heat. This should give you an idea of how much heat you'll need to deal with at various drive currents.


----------



## TorchBoy (Oct 30, 2009)

mpteach said:


> Its surrounded by plastic and battery it not in open air. If heat's not an issue than i could increase the ma  The 600mah lipo can put out 600ma.


 Heat might not be an issue at 250 mA (emphasize _might_) but if it's surrounded by plastic you could start melting things with much more than that. 0.42 W of heat is enough to get not-very-heat-conductive plastic very hot.

https://www.candlepowerforums.com/posts/3125821&postcount=23 has a pic of some 10 mm optics. They don't look hugely deep.


----------



## JohnR66 (Oct 31, 2009)

I think you are over complicating this thing. It looks too thin to be messing with power LEDs & optics. I can see a lot of potential problems with flexing that may reduce reliability let alone shoe horning it all inside.

Just put a couple good quality 5mm LEDs inside. I made a snap on 9volt battery clip that uses 2 Nichia GS LEDs. At only 20ma drive, they are plenty bright to light up a room at night. At 40ma drive to each LED, they should give decent light and last a long time on a charge.


----------



## mpteach (Oct 31, 2009)

JohnR66 said:


> I think you are over complicating this thing. It looks too thin to be messing with power LEDs & optics. I can see a lot of potential problems with flexing that may reduce reliability let alone shoe horning it all inside.
> 
> Just put a couple good quality 5mm LEDs inside. I made a snap on 9volt battery clip that uses 2 Nichia GS LEDs. At only 20ma drive, they are plenty bright to light up a room at night. At 40ma drive to each LED, they should give decent light and last a long time on a charge.



This is 18mm x 37mm x 70mm (w/o silver ring on the back and key closed) measured around the outside center. Its definitely thicker than an iphone and comparible to my current one.

This thing is quite sturdy, no flex, 2mm thick plastic and rounded edges. I could put a brace inside if needed.
Theres lots of small flashlights with everything shoehorned inside. Shoehorning it inside is half the fun lol.

I want my houskey screwed to the bottom because my house and car key are the only ones i really need to carry on me at all times and i can avoid a chain.
I think lipo packs greatly simplify it over having to change coin cells. opening this thing is a pain, theres 3 tiny screws, one which requires prying up the logo and when opened the spring for the key pops out and has to be carefully put back in and rotated tight when closing. A charging jack is a lot easier.

If i dont use a power led im going to use no less than 4x5mm leds across the back. I like bright lights. I like small electronics A low mode would be smart for runtime though.

If i use a power led im going to put a thermocouple in there and test how much current i can safely push in real world conditions, ie fresh bats, high ambient temp and 10min running on a couch bottom side down.

Edit: this will be an edc light. At work i'll use a floody 18650 mc-e light but there will probably be a lot of times when this is my only light.


----------



## mpteach (Oct 31, 2009)

TorchBoy said:


> https://www.candlepowerforums.com/posts/3125821&postcount=23 has a pic of some 10 mm optics. They don't look hugely deep.




Where can i get those optics? If their cheap i'll get several different ones and see which i like.


----------



## TorchBoy (Oct 31, 2009)

Yes they're inexpensive but the shipping isn't nice. I'm told you can enter CPFDISCOUNT for 5% off.
http://www.cutter.com.au/proddetail.php?prod=cut837
http://www.cutter.com.au/proddetail.php?prod=cut937


----------



## mpteach (Oct 31, 2009)

Will an xp-g draw less ma than a xp-e or simply less vf? If its the latter i may just be transfering the heat from the led to the resistor and paying for the privilege. Do they have neutral tinted xp-g?

Assuming the battery doesn't drop excessive voltage and the dimming is noticeable and it can handle 350ma heat wise i'll use a amc7135, and if it can handle more then i'll use a resistor in parallel with the amc7135 for semi-regulation. Amc7135 are very cheap.... and much less complicated than running my 2 300mah lipo packs in series instead of parallel and using a buck driver..heh


----------



## TorchBoy (Nov 1, 2009)

A resistor in parallel with the AMC7135 will result in the LED getting more current. A diode or two (or maybe a resistor) in series with the Vdd pin of the AMC7135 will mean the thing is operating out of regulation but probably in a well behaved manner. It could be fun figuring out the value of resistor you need. The AMC7135 needs 2.7 V and draws 0.2 mA in regulation.


----------



## mpteach (Nov 1, 2009)

TorchBoy said:


> A resistor in parallel with the AMC7135 will result in the LED getting more current. A diode or two (or maybe a resistor) in series with the Vdd pin of the AMC7135 will mean the thing is operating out of regulation but probably in a well behaved manner. It could be fun figuring out the value of resistor you need. The AMC7135 needs 2.7 V and draws 0.2 mA in regulation.



Would a diode in series with vdd reduce or increase current through the 7135? This is a constant current regulator and not a constant voltage so i wonder if it will have any effect besides increasing the min regulation voltage from 2.7 to 3.3. Has anyone tried it?

I know a resistor in parralel would increase current thats why i said if it could handle more than 350ma id add a resistor for extra current. Only the first 350ma would be regulated and the rest direct drive, but semiregulation is better than no regulation and i know 700ma wont happen lol, if it didnt melt it would exceed my lipo specs. The high discharge lipos couldnt fit this thing.


----------



## TorchBoy (Nov 1, 2009)

mpteach said:


> Would a diode in series with vdd reduce or increase current through the 7135? ... Has anyone tried it?


It couldn't increase the current. If it dropped the voltage on Vdd below the point at which it could stay in regulation then you'd get a reduced current from the AMC7135; they drop out of regulation quite gracefully, not in a sudden death fashion.



mpteach said:


> I know a resistor in parralel would increase current thats why i said if it could handle more than 350ma id add a resistor for extra current.


OK... but you'd then be getting perhaps 1 watt of heat dissipated inside a small plastic case. Is that a good idea?


----------



## mpteach (Nov 1, 2009)

TorchBoy said:


> It couldn't increase the current. If it dropped the voltage on Vdd below the point at which it could stay in regulation then you'd get a reduced current from the AMC7135; they drop out of regulation quite gracefully, not in a sudden death fashion.
> 
> 
> OK... but you'd then be getting perhaps 1 watt of heat dissipated inside a small plastic case. Is that a good idea?



It probably wont handle more than that, i guess if it even handles that, i really dont know what it will handle. Lol yea it might be like holding one of those laptop powerbricks lol.

How is using a resistor to drop the amc1375 out of regulation for lower current better than just a resistor? When the voltage goes to low and the amc1375 drops out of regulation doesnt it go to direct drive?

edit: 4 of these flip keys taped together have nearly the same dimensions as my 45w laptop powerbrick.


----------



## TorchBoy (Nov 1, 2009)

mpteach said:


> It probably wont handle more than that, i guess if it even handles that, i really dont know what it will handle. Lol yea it might be like holding one of those laptop powerbricks lol.


I was thinking it might be more like holding a blob of melting plastic. 



mpteach said:


> How is using a resistor to drop the amc1375 out of regulation for lower current better than just a resistor? When the voltage goes to low and the amc1375 drops out of regulation doesnt it go to direct drive?


I've never tried using a resistor like that. Hmm... I suppose the benefit would be in having a current ceiling. Yes, I guess it is direct drive, with a gradually reducing overhead.


----------



## mpteach (Nov 1, 2009)

The inside of those power bricks are lined with copper sheet to spread the heat evenly over the exposed plastic area. Some of them still get almost hot enough to burn you though!

I cant really calculate the thermal resistance so when i get it set up im going to put a thermocouple in there and slowly turn up the current till i reach my maximum safe temperature.

I wish the 7135 was adjustable.

again is there anwhere faster than kai/dx to get the amc7135?Are there any warm xp-g tints yet?


----------



## J_C (Nov 6, 2009)

I wonder how much current you could safely put through an XP-G if you use a big 12 gauge wire for a power lead to heatsink it. Seems easier/cheaper than the other alternative of using a 4mm copper rod, though I suppose instead of an official "rod" you could just get the largest diameter solid core copper wire you can locate, or for more cost effectiveness twist together several strands of 14 gauge, solder plate the end and cut, lap it to a flat surface... think I may end up trying that some day.

Wouldn't it be nice if they made some XP-G with an integral lens that attempted to focus a lot more?

Anyway, if you start lining the sides with copper sheeting it is likely you cut down on the RF range, but we don't know how much margin there is to play with on current distance vs minimal distance you require of it.


----------

