can you elaborate? I was reading some of the Xb datatsheets, interested to hear your thoughts.
What are the TW's. Spotlights?
Thanks again!
The first thing I ever heard about the XB is that they emit out the side of the chip(not sure if that is true, but sounds and looks like it could). So I looked into it and the description of from cree pretty much says it,
"
Optimized to lower cost for high-lumen, omni-directional replacement lamps, the XLamp XB-E High-Voltage White LED delivers high efficacy in the small XB footprint. The XLamp XB-E High-Voltage White LED enables smaller and more efficient driver circuits than standard-voltage LEDs. In addition, the XB-E LED has a wider light distribution that can improve the omni-directionality for ENERGY STAR replacement lamps. These system optimizations combined with the light distribution enable more-efficient, cost-effective and better LED replacements for omni-directional lamps. Built on Crees SC³ Technology Platform, the XB-E High-Voltage White LED delivers up to 364 lumens and 105 lumens per watt at 125 mA and 85°C."
But then when looking at the data sheet look at the spatial distribution graph you can see the pattern is wider than the XT. So when on the tower they will emit a more true "omni-direction" and get the very top of the bulb better than the xt's.
Then we have to remember that it is not really a 1 vs 1 with the chips. The goal for cree is to get the bulb to output the required lumens ~40w=400lm ~60w=800lm...so whatever amount/pattern of chips is required to hit that goal is what they will do. Also, the bin thing I mentioned before. They might be using an average XT bin and better XB bin, so they actually put out the same lm/w. then plus the direction benefits, the XB get the approval.
The TW=true white and are a high CRI(93 instead of 80) version, but they require more watts to produce the same lumens 40wcree=6w, 40wTWcree=8.5w...yet they both put out 400lm. And the chips are the same model...but the high CRI bins have lower lm/w(no matter what company chip).
Now lumens aren't really what I care about for growing, but when the spectrums are nearly identical and from the same company, it will actually be a decent thing to compare with. The true question is what out more par µmols? I testes a WW with XT's vs a CW with XB's, both with globes on, and the WW had 14% more par output surprisingly. But that was only one primitive test and a reflector was used.
What I have come down to is a Cree globe is pretty much a Cree globe, whether xt or xb. But when picking a chip to use in a panels that will be trying to achieve max performance...XT-E all day.