I think I've figured out the weak link in the Arc6.

...the emitter.

I have two Arc6s, one with a Luxeon K2 TFFC and the other with a Cree MC-E. On a whim I decided to test their current draw, each set to Level 7 and using a freshly-charged AW IMR16340 battery. On the Arc6 with the MC-E, the current draw was ~2.3 amps, but on the Arc6 with the K2 TFFC, the current draw was ~4.2 amps! I was amazed; I switched the batteries, in case there was some difference between them, but as I expected, the results were the same.

Needless to say, in addition to the MC-E using almost 50% less power, it also produces a hell of a lot more light. Clearly the Arc6 driver is capable of handling a LOT of power, but with "normal" emitters it's also clearly wasting a lot of that power trying to push the specified current through the emitter. Now I know why the Arc6 with the K2 TFFC heats up so much faster.

The moral of this story is: if you have an Arc6 and you wish it wouldn't assassinate batteries quite so fast, upgrade the emitter. Now that I know the K2 TFFC is thoroughly inferior, I plan to replace it with an SST-50; I'll be interested to see what the results are.

I put an XP-G in one with some very nice results

Swapping to an SSC is also a very nice upgrade, though not nearly as efficient.

I love the package and the UI on the Arc 6 but I could never get over the run-times that it had... I would love to know what your MCE Arc 6 could do in in the output / runtime departments.

Very neat information by the way.

Tekno_Cowboy said:

I put an XP-G in one with some very nice results

Swapping to an SSC is also a very nice upgrade, though not nearly as efficient.

Click to expand...

The one with the K2 TFFC originally had an SSC P4; I swapped to a K2 to get more brightness and better throw. This was before the MC-E was able to do both at the same time while also preserving the Wall O' Light effect that the P4 has.

If the surface area of the emitter die has anything to do with the amount of power the Arc6 driver has to waste to push the specified output power through the emitter (which is my hypothesis), then yes, the XP-G will do quite a bit better, but a wide-die emitter like the MC-E or the P7 or the SST-50 should blow the doors off it anyway.

:)> said:

I love the package and the UI on the Arc 6 but I could never get over the run-times that it had... I would love to know what your MCE Arc 6 could do in in the output / runtime departments.

Very neat information by the way.

Click to expand...

The MC-E I used was rated at 430lm minimum with all 4 dies running at 350mA each. As it happens, the Arc6 driver has a rated maximum of 1400mA, which divided by 4 is 350mA spot-on. So without sphere-testing, I estimate that I'm getting somewhere upwards of 430lm out of it.

Given that all the luddites who've seen the one with the K2 TFFC said "holy s**t!" when I showed them the one with the MC-E, I think that's about accurate.

Does the runtime get any better?

Honestly I haven't been that rigorous about checking the runtimes -- but at the same time, if the MC-E requires half the input power to achieve the same output power, the math says the runtime must improve.