Toshiba yellow 10mm 23,000 mcd LED ?

[vcal]

telephony-
That 10mm Wht. LED output was measured w/newly acquired G.E. Lux/footcandle meter-(LED carefully aimed in jig-12" over the meter's sensor).
Ken-my Photon II output measurements came out very similar to telephony's..
Btw-when the Arclight is delivered, I'll post a condensed
direct light unit output-with % light loss hour by hour...

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
telephony-
That 10mm Wht. LED output was measured w/newly acquired G.E. Lux/footcandle meter-(LED carefully aimed in jig-12" over the meter's sensor).)<HR></BLOCKQUOTE>

Ok, I just wanted to see if you tested the same way I do - by firing the light directly at the meter. If everyone could get their hands on a foot-candle meter, no matter how old or new, we should all be able to get similar results.

My sensor is bolted to the wall below my test target, and I just lay the lights on a magnet mount clip that fits a 3 AA Trek light, that is itself placed on a styrofoam block. The whole mess is then rotated & aimed at the sensor. Laying the light onto this clip allows for adjustments to be made, and places the light at the same height as the sensor. Crude, but it works in leiu of a jig or an optical bench.

An LED that needs to be tested is simply held in the hand by the alligator clips that feed it power, and aimed at the sensor and slowly waved about until the highest reading is obtained.

 

[vcal]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by KenB:
Doug, does your`s show about the same?..<HR></BLOCKQUOTE>
Ken-
I just did a"quickie" test on my Photon II-(WHT) with fresh batteries.
FYI-Initial Lux-Unit brightness was 350 units.
Test was stopped exactly 2 minutes later, and unit brightness had declined to exactly 250 units!-this obviously means that in 120 sec.
this great little light lost almost 29% of it's initial brightness

As telephony said, -it falls off
REAL quickly..(if you really measure it)...........
What do you imagine the loss would be if I left it on for 10 minutes straight???
Also-FYI-Photon was reactivated after 2 minute "rest" and the unit reading shot right back up to 345 units!
-food for thought.............

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
I just did a"quikie" test on my Photon II-(WHT) with fresh batts
FYI-Initial Lux-Unit brightness was 350 units.
Test was
stopped exactly 2 minutes later, and unit brightness had declined to exactly 250 units!-this obviously means that in 120 sec.
this great little light lost almost 29% of it's initial brightness

<HR></BLOCKQUOTE>

All of the coin cell, direct-drive lights will show a very quick fall off, which then slows or plateaus a bit as the battery voltage sags & LED current demand decreases.

Obviously, the larger the battery, the slower the fall off.

I measured my Photon II at 26,000 to 27,000mcd, which falls extremely rapidly (100mcd per second or more)... within about a couple of minutes it's gone down to 14,970mcd. Then the fall-off slows to maybe 15-20mcd a second... 14,040mcd... 13,430mcd... 13,260mcd...etc.

 

[vcal]

Craig, this is Exactly why lots of people wish LRI had gone with the #2032 cells..your thoughts??

 

[The_LED_Museum]

P.S.

For those with light meters capable of reading in foot-candles, to convert that to millicandelas or mcd - the standard measurement used for LEDs, do the following:

With the sensor exactly 1 foot from the LED (or better still from
wherever the rays are diverging from, and such point will usually but not
necessarily be somewhere inside the LED), candela and footcandles are
equal. Multiply foot-candles by 1000 to get millicandelas if you are
satisfied that the effective distance from the light source is 1 foot.

I had to do a bit of checking around to confirm what I already knew - that mcd values would easily come out of foot-candle values, and received that confirmation this evening. I had to be sure first.

So if your physical measurement is reasonably accurate, your light measurement will also be so. And the conversion is so easy...

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
Craig, this is Exactly why lots of people wish LRI had gone with the #2032 cells..your thoughts??<HR></BLOCKQUOTE>

At 6 volts total, a pair of CR2032 might, just might have enough energy to deliver the fatal blow to an LED connected directly to them.

The CR2016's won't do it because they can't deliver a couple hundred mA to the LED.

 

[vcal]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by telephony:
At 6 volts total, a pair of CR2032 might, just might have enough energy to deliver the fatal blow to an LED connected directly to them.

The CR2016's won't do it because they can't deliver a couple hundred mA to the LED.<HR></BLOCKQUOTE>
Have you tried (like I did) that
xperiment with 2-2032s hooked up to a Nichia "5600"?-didn't notice any problems (only left it connected for about 45 min.), but didn't take any measurements though.........

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:

Have you tried (like I did) that
xperiment with 2-2032s hooked up to a Nichia "5600"?-didn't notice any problems (only left it connected for about 45 min.), but didn't take any measurements though.........

<HR></BLOCKQUOTE>

Sorry, I haven't tried.
I don't have any CR2032's here with which to try it - I lost all of my coin cells in the quake due to immersion in water from a broken fishtank.

Good instant project: someone who has these things hook up a white LED to a pair of them and meter it for current.

Most important reading is when the LED first comes on... if it spikes much over 130mA to 150mA during the first few seconds, it will probably shorten the LED life quite dramatically, and some LEDs (not all) may even blow out at this point.

Yours may have worked, but that doesn't mean everyone else will be as lucky.

Then again, if the current on NEW batteries stays below 120mA or so, there may not be a problem with using this larger cell size.

 

[vcal]

Additional point of interest(?)
Just did output longevity experiment with Pelican L1.
Initial output=340 units
Aft.2 minutes=300 units
" 5 minutes=295 units
" 10 minutes=285 units
" 15 minutes=277 units
" 30 minutes=255 units
-hey, this could be Addictive,-I think I'll quit while I can...

p.s:batts were thoroughly
pre-checked B/4 doing that.
(4-L.R.44s)

 

[Badbeams3]

I don`t have a light meter yet

...but the Bison clip light I have uses two 2032`s with a Nachia 5600 and it does not burn out the LED if left on. I bet it drops the batt volt quickly as well...but it does seem to run a lot longer than the Photon

 

[vcal]

Ken,-does that bison light have a stay-on switch?

 

[MY]

I have a Lightwave light which I am using 2 2032s. I took out the foam spacer and shaved a little of the backing off the cover. The cover fits albeit pretty snug. The light burns brighter and for about twice as long as the original batts.

FYI: my local home improvement store Lowes sells coin batteries, all sizes, for $1.09 each. You might want to check out your local Lowes.

 

[Badbeams3]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
Ken,-does that bison light have a stay-on switch?<HR></BLOCKQUOTE>

No, you have to use a clothes pin...if it did it would be a nice light...I ran it constant for about a half hour looking for sea shells when I first got it...Bison told me they were coming out with one just like it with a I/C on/off switch...not water resistant though and using 2025`s to allow for the space the I/C will take.

My, neat idea, I might have to try that with mine

 

[Brock]

Craig and Videocal I need to get a good light meter, but when ever I look on EBay I find over 100 and have no idea which one I should get or which ones are good. Any tips on search words, ie "light meter camera" or something along those line?

Brock

 

[Badbeams3]

After looking at my Pocket Bright and seeing how easy it would be to do what My said...it makes me wonder why they are not made for the 3032`s...makes me think that Craigs thought about running the led to hard may be why...perhaps the Nachia will tolerate the larger batts for a while but...maybe shorten the overall life enough to where conserns about warranty replacments might have been why they decided to go with smaller batts...it looks almost like useing 2032`s was the original idea but...after the case mold was made they changed their mind and for some reason went with 2025`s instead. Might explain why the Pockat Bright`s are so needlessly fat too.

 

[vcal]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Brock:
Craig and Videocal I need to get a good light meter, but when ever I look on EBay I find over 100 and have no idea which one I should get or which ones are good. Any tips on search words, ie "light meter camera" or something along those line?

Brock<HR></BLOCKQUOTE>

Would really recommend (if you can afford about.$75.or so).that you get a digital one.
-just index in search: "digital light meter" and you'll find several..

 

[Chris M.]

Me too. One would be a very handy tool for life-testing, comparisons and stuff like that. I`d like to include Candela brightness figures in my reviews (patience please, they`re coming!), I think that would be very useful.
I can`t afford the very best meters but if you could suggest a good one (digital?) for under, say, $60 then that would be great (if you`re pointing me to Ebay make sure they will ship overseas too)!


By the way I had one of those Toshiba LEDs that started this thread off. As good as useless as a flashlight but pretty good in the garden- on dark foggy and rainy nights it left a fairly noticeable streak through the air, I had an idea to use a few for some interesting lighting effects. Craig- how much would you sell those ones you have for (email me!)? I`d be interested in seeing the whites too cos I`ve never seen a 10mm white before. They might work better cos the blueish light would contrast more against the orange light-pollution glow in the sky when it`s cloudy. The yellows are almost the same colour as sodium lights.

 

[Chris M.]

Would really recommend (if you can afford about.$75.or so).that you get a digital one.
-just index in search: "digital light meter" and you'll find several..



Don`t know why I didn`t think of that! Too many late nights I suppose. Web design is fun, isn`t it.....?

 

[Chris M.]

The catalogue has these at around $3.50 apiece. I can let some of them go for $1.50 apiece.

Those $7.00 white ones - how about two bucks each, but I need to find them first.



Sounds good to me- let me know when you`ve found them. No hurry, I still havn`t figured out quite how Paypal works...