Fenix P2D/Romisen - Heat

Hello.

I have a Fenix P2D Q5 and a Romisen RC-N3 Q5.
With the Fenix on high (not turbo) they both seem to put out a reasonably similar amount of light. The only difference is that after a few minutes the Fenix is quite a bit warmer than the Romisen.

Is this...

A. bad, the Fenix is generating more heat than it should.
B. Good, they generate more or less the same heat but the Fenix dissipates it better.

Note: Neither is hot, it's just that the Fenix is definately warmer than the Romisen. Based on them just sitting on a table untouched for a few minutes.

Any knowledge on this would be greatly appreciated.
Thank you.

In the abstract, it depends on which one runs longer, assuming outputs actually are equal. If the Fenix runs longer, it's good because it means that the Romisen is generating more heat (what doesn't come out as light must come out as heat...) but the Fenix is doing a better job of cooling the LED by heatsinking. If the Romisen runs longer, it's bad because it means the Fenix is less efficient than the Romisen. On the other hand, the Fenix LED might still be better protected than Romisen since the excess heat is getting wicked away.

If the Romisen lasted much longer than the Fenix, then the Fenix might be down on both counts of efficiency and heat sinking. I'm not familiar with that Romisen, but Fenix generally has pretty efficient circuitry so I doubt it's the last case.

Thanks for that.

My claim of a similar light output might be off. I think the Romisen appeared to be more due to a tighter beam. In reality (and a proper nighttime dark test) it's likely the Fenix on high is a higher light output. I also noticed that the Fenix on medium, which is still quite bright and rated as 55 lumens/5.5 hours runtime, doesn't seem to generate any heat at all.

Another thing that could be in play comparing lights is that even with the same efficiency, the same power being applied, and same thermal transfer capability from die to body, some bodies just have more metal. A beefier head that starts at the same temperature simply has more ability to absorb heat before reaching the same temperature.

From the pictures, the RC-N3 seems to have more metal then the P2D, that might also be the reason for the difference in heat.

I'd say it's not a problem.