Heat issues LED vs Incan in G2

One week after getting my Surefire G2 I switched out the P60 bulb and CR123 batteries for a Lumens Factory HO-9 bulb and AW RCR123 rechargables. I found it to be very bright for its size. However, after about 60 seconds of use, I could feel the lexan lens getting very hot. Whenever I aimed the G2 at my skin from 6-12 inches away I could also feel my skin get warm after about 10 seconds.

I recently got a Cree LED drop in from kaidomain that fits perfectly and outputs a similar amount of light (slightly less, with a typical LED colour profile). When used for 60 seconds, the lens is completely cool, however the part of the G2 body where the first battery is stored begins to get warm.

I would much prefer to use the LED drop in since it is less prone to breakage and has a longer lifespan, as well as longer runtime. The heat in the G2 body causes me concern. Will this damage the batteries?

The heat generated by the incan seems to be directly forward out the front of the light, instead of inside the body. Switching to a UCL glass lens would probably fix any heat problems in the lens.

Incan lights emit infrared light, which is what causes material it hits to heat up. In the case of the G2, the lens is made to handle that kind light (well, with the normal LA's at least, don't know about the LF HO-9).
with LED's it's the electronics that are emitting heat, so that stays inside the body.
Li-Ion batteries deteriorate with higher temperatures, but this is more referring to long-term storage. Short burst (1hour runtime i guess?) is nothing compared to storing them for months at high temperature, but i don't know the specifics of how those short burst affect it's ability to keep a charge.

The LED module's only route of conducting heat in a G2 would be the metal lining and the batteries, as the nitrolon insulates the heat. I wouldn't leave it on for long per se as this could damage the LED or shorten its lifespan, but you gotta strike a balance between using it and "protecting" it. Overheating the battery is also possible.

I like to keep in mind that most of these lights are "tactical" lights, and not supposed to be kept on for long, it wasn't too too long ago a SF 12PM/Z/P would only run a few minutes before going into thermal shutdown.

At under $15 for the LED drop-in, don't baby it. The life and output degradation from heat is relatively minor and not normally noticeable unless directly compared to a new one. Costs the same or less for a comperable incan. If using primary lithiums (observing NOP for series batts) don't baby those either as the assembly doesn't under normal use draw enough current to cause damage plus they are meant to be disposed anyway. RCR123's deliver higher voltage and therefore the module draws less current and batteries are stressed less. If you remember, mark the RCR123's so you can alternate which one goes in first. I've unscientifically noticed the one closest to the head usually comes out at a lower voltage. Theoretically there shouldn't be a difference but... Use it and have fun. YMMV

maybe that idea concerning the cost is good for You, maybe not, it sure is a new point of view to consider.

I for my part think there is no way You can exaggerate hatsinking and thus would never ever use any Led thing, running on high current, in a non aluminium light.
f.e. my 6P Cree mod gets quite warm within 10 mins of use. Not hot, still possible to grab it, but surely very warm, totally, head + body + part of end cap. And the led is placed on a 1 cm thick heatsink press fit into the aluminium light.

At Yours the heat just cant get away and so the degradation of Your unit, when running on comparable current than my light, will be noticeable within this year for sure
except if You use the light fors bursts, then its ok.
(extreme example: no heatsinking --> burn out in some secs)

Cost is no issue. My concern is purely about safety and reliability. I don't want the AW RCR123 rechargeable batteries to explode/overheat, and I would prefer to use an LED over Incan due to the shock protection and longer lifespan.

Cost wise, I would have no problems with upgrading to an aluminum light like the 6P, however I don't because I actually prefer the nitrolon material.

My general use is less than 30 seconds 60% of the time, less than 60 seconds 99% of the time. From the feedback I have received, it sounds like this won't be a major issue, I just may shorten the lifespan of the LED, and maybe the batteries as well. Hopefully I never have to use it in that one random emergency situation where I need it for 20 minutes constant on.

I'm still rather undecided. I'll have to think of the pros and cons of each further. Thanks for all your input, and if anyone else has more information, please do let me know.