# XP-G2 vs XT-E



## fedcas (Dec 19, 2013)

Hi everyone,
i haven't found much information about XT-E but i think it's a pretty interesting LED, in particular, i think it's worth considering it as an alternative to the XP-G2.

Both are rated at exactly the same @ 350 mA:

*Flux (lm) @ 85 °C: 139 lm
(Cool White R5 @ 350 mA)*

The main point of the XT-E should be the different emispherical emission, due to the particular shape of the inner optics:










comparing the polar distribution from the datasheets:






so basically the XT-E has more side emission and the hotspot slope is more linear








it is slightly less efficient, but the difference is less than 2% at 350mA. The voltage gap gets relatively bigger at higher currents though.







also, the output at 350 mA is identical, but again it gets quite lower at higher driving currents.






So i would say i'ts an interesting alternative for low driving currents. I swapped the XP-E of my Black Diamond Storm with an XP-G2 to get more flood and more efficiency, but i'd still like a bit more flood and also i got a slight blackhole in the hotspot. According to the graphs, I guess i should have improvements on both sides if i swap the XP-G2 with the XT-E... and the driving current is around 400 mA so the efficiency should not be affected. I have an XT-E right next to me... i'll post a beamshot comparison afterwards


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## degarb (Dec 19, 2013)

I got an R5 xt-e dropin out of curiosity. With the reflector, the color makes me sick: it has sever color issues. But, if I take off the reflector any weird color issue goes away. I do wonder if it would make a good swap for the hp25 flood, or if the color problem would be noticeable under the optic.


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## mds82 (Dec 19, 2013)

according to http://pct.cree.com/dt/index.html they are nearly identical output in the same bin rating. only about a 5-20 lumen difference across the board


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## fedcas (Dec 19, 2013)

degarb said:


> I got an R5 xt-e dropin out of curiosity. With the reflector, the color makes me sick: it has sever color issues. But, if I take off the reflector any weird color issue goes away.



you mean you dedomed the led?


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## AnAppleSnail (Dec 19, 2013)

fedcas said:


> you mean you dedomed the led?



There is color separation in the primary optic (Dome) that is focused and enhanced by the secondary optic (Reflector). The different angles of intersection on the light-extracting dome act like a prism. I remember this happening when the XP-E was replaced by the next one in line. You may 'fix' it by shimming or fogging your reflector slightly to reduce to concentration of funny tints.

It looks like a nice even flood with the reflector off, but the edge of the beam has those colors that the reflector scoops up so nicely.


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