here is a chart of what lumens it is possible to get out of a single XML
in Lab conditions at all drive currents .
I will leave you to work out who is telling porkies in their advertising
for some pretty ludicrous lumen claims .
Bike Forum
XML Lumens what is possible and what is bending the facts a tad
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Posted 7 months ago #
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Good bit of work there Troutie
Posted 7 months ago # -
Not my work Smudge I only cut and pasted it
Posted 7 months ago # -
Hard facts are no use to us, this is mountain biking, and we demand a diet of fantasy and marketing bullsh*t!
EDIT- The Dominator is stunning, dont need lists of figures to work that out either
Posted 7 months ago # -
Don't let messy things like facts get in the way of a good story.
Posted 7 months ago # -
I will leave you to work out who is telling porkies in their advertising
for some pretty ludicrous lumen claimsTrout.
As we discussed earlier this year.
If whomever it is that you have found to be enhancing their claims, is within the juristiction of the ASA, then they should look into it.Incidentally, in back to back testing of XP-G to XM-L, I can certify that the approximate increase in lumens of the X-ML over the XP-G is......... 16 lumens upto a current of 650ma, the max current I have conduted testing at.
Same real world conditions, basically I constructed a light identical in everyway to a retail model and then got it independantly measured.Obviously, the XM-L has its main advantage over the XP-G in the fact that it takes higher currents.
You didn't answer the mail I sent to you and Smudge, last week.
No doubt your tempremental ISP again.
I hope all is well at the Hatchery.
Posted 7 months ago # -
Luminous/trout
I know your test didn't run XPE/XPG led's but what Lumen output can i expect from XPE/G leds run at 850mA? Is it that i run 3 of them at that current that i get a (presumed) similar Lumen output to a single XLM at 3 amps?
Oh and thanks for frazeling my brain this early on a Monday morning
Posted 7 months ago # -
RM.
Get over onto the Cree website, and you will see docs and graphs with outputs for the LEDs you mention.
However, as you will know, these figures are recorded under lab conditions.
In the real world we have to account for LED temperature when in operation, as this will have a direct result on the lumens you might hope to see from the front of your light.
So, for an empirical figure of Lumens at any said current, refer to the Cree documents.
If you really need to know the actual output from your light, we know a nice man who measures lights. Posted 7 months ago # -
James Got your mail picked it up on the Ipad then upgraded the damn thing to ios5 and lost all the mails for some reason
will find it on the virgin server I GuessRusty I have charts with the XPG XPE lumens will post them up when I find the photos
xpg @ 800 ma = 295lmns and @ 900ma = 324lmns
XPE @ 800 ma = 217lmns and @ 900ma = 235lmnsPosted 7 months ago # -
imperical figure of Lumens
do you mean a figure in candlella or "empirical" ?
Posted 7 months ago # -
Have a look at PCT from Cree.
That gives current vs lumens. You have to register for this.
Also OVERDIVE INFO which might give a clue about those Lumen claims in peak mode.
Posted 7 months ago # -
No worries Trout.
It was just a "how you doing ?" e-mail.
Edit.
Anyway, I can't stand the suspense.
Who do you think has been fibbing about their XM-Ls ?.
Posted 7 months ago # -
According to some boffin on candlepower via the power of google I give you the XPG R5 table
And the Mc-E table
Posted 7 months ago # -
Who do you think has been fibbing about their XM-Ls ?.
Just about everybody who sells a light, present company excepted of course
Thanks Tomaso beat me to it in the search skills
Posted 7 months ago # -
Is the MC-E chart accurate as is appears to offer more lumens for a given MA?
Posted 7 months ago # -
Hi Trout, I sent you an e-mail regarding purchasing an H6FLEX driver for one of your Twin XML DIY kits that stopped working, did you get it, or was it lost in cyberspace?
Doug
Posted 7 months ago # -
Never saw that one Doug but yes can do .
George @ taskled is on hols at the moment but if you mail him he might be able to fix the old one too.
Posted 7 months ago # -
Thanks all for the replies and the links, i realise these figures are all generated in ideal conditions which are unobtainable in a torch or lamp of any usable size for biking. I was just curuious as to what i was likely to be getting from my Lumicycle halogen LED conversion lamps i am running at the moment.
It looks like my brain is kind of switched on this morning as my innitial estimate of 900 ish on paper lumens is about right for the three LED's. I'm guessing a more realistic value is going to be about 750 -800 lumens taking into concideration 20% losses (guessing at this figure).
One other guess into the facinating world of LED's -
Mc-E LED's they look promising from a curent in to Lumen out point of view but are they simply not that common because of the comparitively high voltages involved in generating the output?Posted 7 months ago # -
another real world consideration is the reflector and the lens/glass cover.
The reflectors will absorb 1-2% of the light, and assuming it's glass on the front that will loose another 4% unless it has an expensive anti refelctive coating on.
So a well designed and light tight system will loose ~5%. Most will leak a bit of light in other places too.
Posted 7 months ago # -
Hi Chris
Be cool to know the before and after lumens from one of the hope 2s
you dont have a mate with one you could test and send it in for an upgrade and test afterPosted 7 months ago # -
not im my immediate riding circle, I'll ask around and see.
Posted 7 months ago # -
That graph must be one of the worst representations of data I have seen in a while... at least the x-axis intervals are some of the most random. It's quite hard to interpret much below a 2A drive current.
I guess that the other advantage of the xml over xpg is the reduced vf which gives better efficiency.
Posted 7 months ago # -
right, i have no idea what i just read. trout i have used my dominator tree burner a few times now. only charged it when it arrived and have ridden 4 times!
stoopid bright doesnt appear on that chart
Posted 7 months ago # -
Sorry for my ignorance but putting this in laymans terms if im using an 18650 2800mAh battery on a XML-T6 then i should be getting about 852.2 lumes
A cheaper Ultrafire 300mAh battery listed on torchies site atabout 1000 mAh should be about 392.
Am i barking up wrong trea here - obviously i expect lossage aws discussed earlier.
Posted 7 months ago # -
carbon,
the lumen output will be determined by the current that your driving the LED at. Normally determined by the driver you are using.
The battery capacity (mAh) will just influence how long the lights will run for.
Posted 7 months ago # -
carbon337
you are missing the 3rd component to the light - the driver board.
In generalities the driver board controls the current going to the LED rather than the battery.
Posted 7 months ago # -
ah ok how do you find out the driver output to the led then?
Posted 7 months ago # -
Finding out the driver output is kind of tricky, I know what is in mine as i built the lights and i bought a 830mA driver board, other driver boards can be programmed to work at different outputs, the TaskLED boards are a prime example of this.
Some of the propper light boffins may know of a way of measuring it but i don't know how.
Posted 7 months ago # -
Drive current should be listed in the specification of the driver or light that you have.
Otherwise you could measure it (but finding the relevant specs. would be much easier...)
Posted 7 months ago # -
EDIT, Troutie Pmed
Posted 7 months ago # -
Hi chris,
any chance of having a peek in your inbox to see if my e-mails are sitting in there?
ta
john
Posted 7 months ago # -
Toutie Chris - I've located a hope vision 2 - you have mail
Posted 6 months ago #
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