frica
Well-Known Member
And you don't think your way of measuring this is flawed?just measured the heat of XTE royal blue - and i have bad news for you.
Too much heat !
Too much lumen/W ? I don`t know - but it`s hard to believe. I`m just confused.
How can they(cree) believe in 619.7 lm/W ???????????????????
There must be something wrong on this page:
http://pct.cree.com/dt/index.html
0.350 A ......................here is the data for your mentioned XTE royal blue @350mA
650.7 Led lm............. data for lumens must be fake. Several other blue data also - compare to
619.7 lm/W................ XM-L wich seems to be more real.
3 Vf
1.05 Led W
0.500 A ..................... i measured the heat of XT-E @ 500mA with 3,08 V for ten minutes
888.5 Led lm............. and i received 1,3W of heat power. That means around 80% heat power
574.7 lm/W................ from input.
3.09 Vf
1.546 Led W
View attachment 3908120
So the reference, when you say up to 57% efficiency can`t be the total input of electrical power.
Maybe your 100% is part of the electric power, that is ! not ! converted to heat.
The light transmittance is still very good. I estimate >90%
Blue light passes much better through water than red light.
Even if 10% - 30% of the light energy would be lost in the water and get converted into heat -
wouldn`t explain 80% heat energy in total as in a coolmac led system you can store ~ 60%
of total input as heat energy if you tap it only from the backside of the chip and let the light stream free to the room.
The balloon is still trapping a lot light, transmittance isn't the only factor. If light exits the surface part will be reflected back into the balloon, depending on the angle it's a small part or everything can be reflected back.
Cree has sphere tested their chips, which is far more accurate than a condom wrappen around the chip.
You're assumption is that your test is perfect, or at least close enough and that if results aren't like what Cree has tested then it must be that your test is better, it doesn't work that way.
How is heating a condom better than sphere measuring the total light output, and measuring the electric input power?
Your test isn't accurate because you don't factor in internal reflections which has nothing to do with transmittance.
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