Thanks very much for the response. I've had an internal debate for weeks on buying copper PCB xmls (instead of aluminum) for a project. I think it will be worth the extra money to buy copper.
I think you're right about the impracticality of a peltier. But let's hope for some new advancements in battery technology to change that :)
Even if they do, it will probably be up to us to build such things - at least on MY budget...
That's crazy I have been pushing XPGs to 2.2 amps (8 chip Nanjg driver with 2 removed) because that's were they looked the brightest by eye and it was right on the money.
Thanks Match! Been waiting for this info to build my XP-G project. Question now is, is it worth the sacrifice of runtime to get a little more light. I'm looking at 600mA to gain about 50 lumens. I don't think it's worth it. Still seams like 1.4A is the sweet spot for runtime vs. output.
oldbobk,
So are you saying the affect on runtime is negligible between running 1.4A vs. running 2.1A? That doesn't make any sense to me.
I also don't know if I'm up to the challenge of removing two of those chips! I'd probably look into the newer KD driver (and deal with a lousy low, or go 2 mode).
The difference in run time with a 2400mah battery would be about 100 minutes for the 1.4 and 70 minutes for the 2.1 amp high, but I never use high when I am concerned about runtime.
Send me a PM when you are ready to remove the chips I can walk you through it or I can send you one premade if you want.
Thanks for the offer Erik! I am definitely keeping you in mind for a custom P60 drop-in or even just a custom programmed driver (think I'd like Medium a bit higher than the usual 30%, or even 4 brightness modes) for another mod.
100 minutes vs. 70 minutes sounds considerable (for my application), so therefore I don't see the gain of 50 lumens worth the 30 minute trade-off.
Don't want to be a spoilsport but please remember that Match's curves are only valid for a heavily cooled emitter. The top points for the curves in real life lies at a much lower amperage because of the generated heat .
[EDIT]: Calculations using Cree's derating curves give me for a "normally" cooled flashligt a top on the curve at an LED output of:
370-400 lumen @ 1.8A for XP-G R5 and
730-780 lumen @ 3.5A for XM-L T6
but the top 30% of the current only add about 12-15% of light output.
OTL (out of the lens) output normally are about 80-85% of the LED output.