photon vs. overdriven keymate.

nitebrite

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hi all, i hope this doesnt sound stupid since i think i know the answer. i have a keymate that through great pains i have modded to a regulated 9 volts. it also has a glass optic. i would say it's output would be very comparable to a blue e1e if there was such a thing.

this just may well be my favorite light since i slaved to make it. the only problem i have with it is that it is a tight fit with a leatherman in my pocket.

now i was in a store and tried a photon and the inova keychain light. in the well lit store they seemed quite bright. i did not have my keymate with me.
my keymate is what i consider the minimum usable output of a flashlight.

ok now for the stupid question. if i buy the photon and shine it on the wall next to my keymate am i going to be very dissapointed? is the photon even as bright as a stock keymate? if it was as bright as a stock keymate i'd still consider it given it's much smaller size. however, any less output than a stock keymate i personally find completely useless for anything.


thank you,
nitebrite.
 

paulr

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You're running a 5mm led on 9 volts regulated and it didn't pop instantly? Better check that voltage while the light is actually running.

All these lights (keymate, photon, etc.) run their leds about as bright as you can run that kind of led. If you want something brighter, get a Luxeon, or a multi-led light, or a small incandescent.
 

nitebrite

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you are right sort of. i have 9 volts worth of batteries in it. i should have stated that the led is actually not seeing nearly 9 volts though. the internal resistance of those coin batts lowers their output drastically under this type of usage. plus the regulation circuit draws power. the batteries actually provide about 8 volts and under load the led sees about 7. however i think i have managed to provide that 7 volts for the duration of the life of the batteries. then of course it just cuts out abruptly. so i do not get hundreds of hours of unusable light like it normally would provide.

anyways i was just wondering is the 3 volt photon as bright as a stock 6 volt keymate? if it is i will like it. on the other hand, regardless of what actual voltage my keymate's led sees i maintain it has a coparable lux output of an e1e which i find rather impressive. although i do not have a light meter so i may be completely wrong about this. i am just going by shining it on the wall next to the e1e. the e1e does have more spill though. but i like the blue of the keymate better than the yellow of the e1e.


nitebrite.
 

paulr

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I don't believe that 3 coin cells are delivering 7 volts to the led. Have you measured it?

I can only amplify what I said before: these lights all use basically the same type of LED, and they all run the LED about as bright as you can run that LED. Any brightness difference between them is going to be pretty minor. If you try to put more current through the LED, you'll probably burn it out pretty fast.

I feel that people who fetishize brightness with this type of light are on the wrong track. If you want something brighter, use a different type of light. For example, if you like the Keymate form factor, Lambda has done a beautiful Luxeon mod for it using an N cell (Nano-illuminator). Those show up on BST sometimes. There are also some Luxeon-modded Arc AAA's and so forth. Or you can get a Firefly...
 

nitebrite

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as far as i know the stock keymate runs at 6 volts? the keychain lights(photon) run at 3 volts. if they are the same led i would think the keymate is brighter. all i know is that my keymate is much brighter than a arc aaa. my keymate is NOT running on 3 or even 4 cells! it is indeed running on a taken apart 21/23 minus one cell to allow the regulator to fit in the head. like i said it's output is very comparable to a e1e. i guess i will just have to go buy the photon to find out. if i don't end up using it, it is still cool to put in the drawer.

nitebrite.
 

Doug Owen

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[ QUOTE ]
nitebrite said:
as far as i know the stock keymate runs at 6 volts? the keychain lights(photon) run at 3 volts. if they are the same led i would think the keymate is brighter.

[/ QUOTE ]

I don't know the Keymate, but 'all' the white keychain lights use *two* cells, are 6 Volts. As Paulr said, they're about as hot as they can be as is, some over 100 mA when new. Scary, even.

Doug Owen
 

tiktok 22

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Hey Doug,

you are right. White(among other colors)Photons are driven with two 2016 lithium coin cell batts. 3 volts apiece. Driving a 5mm LED with one extra volt would probably only yield marginal gains in output, but *might* lead to no output if it pops your LED.
 

kitelights

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The KeyMate uses 4 alkaline button cells (6v) and is substantually brighter than the Photon style lights or an ARC AAA. I suspect the reason is the large head with the reflector. I don't know what the run time is, but I would think that an hour would be a generous guess before it drops off substantually.
 

nitebrite

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ok you guys have provided the information i wanted. thank you. kitelights, i figured it was a lot brighter.
the keymate is known to run just fine on 5 button cells.
i did not know the photons ran at 6v., i thought they were 3v. my photon runs on a taken apart 21/23 battery minus one cell to fit my regulator. it runs about for about 45 minutes to an hour(didn't time it) and then cuts out all at once pretty much. i know that the amount of batteries i am using is way more voltage than it can handle. but like i said the internal resistance of these batteries drops the voltage a lot. plus the regulator circuit draws almost a volt. the led is seeing 7v. in mine which it is known to handle just fine. the only difference in mine is i get maximum output for about an hour than none. instead of continous diminishing brightness from the moment i turn it on followed by hours of useless output.

anyways, i stated i think mine is as bright(lux) as an e1e.
hot spot is about the same. the e1e has some more spill. the keymate is blue. the e1e is yellow. i am just going off off of shining them on the wall. is this possible or am i just being nuts here? maybe i am too excited that i spent like 20 hours building this and am seeing things?


nitebrite.
 

gwbaltzell

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The 21/23 is an alkaline battery made up of (8) 1.5 V buttons cells (LR932). It has a very high internal resistance and can't deliver a high current. At best the total capacity is 40 mAh. So with six buttons to give 9 V the total capacity would be no more than 288 mWh. Assuming a converter efficientcy of 70% would gives us 202 mWh. If running for 45 minutes the instantaneous power must then be 269 mW. The 7 V must be without the LED connected. If we use the typical 3.4 V the current through the LED would then be 79 mA. Well beyond the max. rating of 50 mA but not unheard of. I really doubt that cells could supply the average 16 mA to drive at this level. Brighter than a 15 lumen E1E? Well if the light is focused in a much tighter spot. Anyone know the angles of each?

BTW 2016 cells are rated 75 mAh so two would give 375 mWh. One 123 cell is about 4000 mWh. edit: The four A76 (LR44) cells the keymate is made to run on are rated a total of 720 mWh.
 

nitebrite

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the 123 has a much higher mah. it is a more robust battery, therefore provides more current for longer. i think you were exactly right as to why i think it is brighter than an e1e. like i said it has much less spill than the e1e. it is focused much tighter than the e1e. as to it actually being brighter i don't know since i am just going by shining them on the wall from 4 feet away. would i have been better to run the keymate on 5 lr44's? if i did this i could not fit my regulator. i am going to kick myself if i would have been better off with 5 lr44's! i tried that originally and think this provides a much brighter light over it's duration.

anyhow, i went to the store and checked out a blue inova microlight. in the store it looked much brighter than my keymate! so i bought it. but once outside it was no where near as bright as my keymate. the keymate had like 5 times more throw, was white(inova had blue led) and had a much larger spot. i think this is the same reason i think the keymate is brighter than the e1e. as the spot gets tighter it appears brighter. whether the lux meter would say it is brighter i doubt. it is simply an optical illusion i think.
with the inova's tiny spot it seemed way more intense. but was barely usable as a flashlight compared to my keymate. the microlights would be great to find a keyhole at 6 inches. that's about it i think.
oh, and one more thing you were also right about the voltage i got 7v. after the regulator, not powering the led.
8.7v. without the regulator.
would 5 lr44's make this lamp brighter for at least the 45 minutes i get now? if so i wasted a lot of time. nonetheless i think even the stock keymate is brighter than a microlight. it should be. it weighs as much as four microlights. it has to be the large reflector, where the microlights have none. the photons are not even sheilded. i would think you loose a lot of light right to the sides with those.


nitebrite.
 

paulr

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If you want the brightest possible hotspot and don't care at all about spill or beam diameter, get a keychain laser and be done with it.
 

nitebrite

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actually that is not what i am looking for. the keychain lights have such a tight beam they are useless imho. my keymate is rather amazing for it's size, even though it is bigger than a keychain light. i was trying to get something smaller than the keymate. however, i have come to realise that the keymate is going to be the brightest thing that fits in my pocket even if it is bigger than a keychain light. it has a beam diameter 5 times the size of a keychain light and maybe 5 times the throw.

now all i need to know is, if the keymate will run brighter on 5 lr44's instead of 6 of the cells from the 21/23?
the lr44's have much more mwh. i'd rather go for brighter than longer run time. i do not have a light meter and can't tell much of a difference between the two battery configurations by sight. that is why i am asking. i would think it may be a simple matter of math here, but i don't really know.

thank you,
nitebrite.
 

gwbaltzell

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No, the LR44s are also alkaline and would likely just give more run time. Trying to run without the regulator would probably destroy the LED. If you are going for the highest brightness and don't care about color use a blue-green (cyan) LED of the same angle. Blue-green is at least 2.5 times as effective to human vision at low levels. See my web page for a detailed explanation. (click my initials and then click night vision - the red myth)
 

nitebrite

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thank you gwbaltzell and paulr. you have helped me understand more about this stuff.

nitebrite.
 

gwbaltzell

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Just remembered something you might think about. There is a battery made up of 4 LR44s, called (strangely enough) 4LR44. Now, don't leave me yet. I know you went to 9 V instead of 6 V. The thing is the other number for this battery is 28A. Which brings us to the lithium version, the PX28. Exact same size as the 28A (4LR44). Still, 6 V you say. The thing is how long it maintains its voltage and how much better can it deliver higher current. I don't know how well (or if) it will fit the keymate. Or even if it will out perform the 9 V worth of LR932s. But it might be worth trying!
 

kakster

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I tried one of the 4LR44s on my Keymate (silver oxide, not lithium), and it wont fit. Its ever so slightly too big in diameter to fit in the battery tube.
 

nitebrite

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why not just take the 4lr44 apart and use the cells like i do with the 21/23? is it the same type of thing as the 21/23 where the case opens and the cells are inside?

i stated that i think this thing is as bright as an e1e. well, a friend has a nanomate and i would be pretty sure it is brighter than that too. i don't know if it is just our imagination but we both agree on this. i would think for that led to be pushed that hard it would have popped long ago. maybe i just got a good one. without having a light meter i want to ask do you actually think this is possible, or just an illusion due to different beam shape etc.?
maybe the 7v. that my 5mm led is seeing is driving it much harder than the n-cell on the luxeon? i'd think that the n-cell is barley driving that luxeon.


nitebrite.
 

kakster

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I think your eyes are being tricked by the higher colour temperature of the LED. Those 5mm LEDs are rated for no more than 2-3 lumens when driven at spec. I think even if overdriven, it would have burnt out long before hitting the 15 Lumens that the E1e puts out.
 
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