3x18650 w/ cree T6 xml or R5

I am green when it comes to building a light and lost on the lingo. I have so far just done drop ins and was completely amazed at the differences,learned about the like batteries and hazards with using the improperly. My favorite I have now is my fenix tk30 that I have used and abuse at work and it just doesn't quit ,my only issue is the head size. So I ordered a 2x18650 ultra fire tube and bezel with s R5 module,went cheap cuz I didn't know if it would work, any info or suggestions would be great.

well, i'm not really sure what you're asking but and R5 is an XP-G (i think). So and XM-L would be able to handle about twice as much power and put out about twice the light.

I'm going to go out on a limb and assume you want to mod it for max brightness? a lot of the LEDs tend to have in the area of 100 lumens per watt. So more brightness means less run time (and means more heat too). So keep that in mind, you might not find it useful to have super powered light for only 5 min.

My idea is to have a p60 size light module with at least 3 modes (high,med,low) that will run as long as my fenix TK30.
I carry my fenix at work in my pants small side pocket on my leg and the head is just a bit bigger than I want but the light can go for several days without recharging,I figured by the xp-g's voltage rating and the 18650 output that this would be a good combo for what I'm wanting,I believe the xp-g I ordered was good for 3-18 volts and I couldn't find an xm-l rated that way. I don't have much invested so its not going to be a heartbreaker if it doesn't workout but that's why I'm asking ?'s from some educated individuals.

most LEDs have a very narrow voltage range in the 3-4 volts area (infact most LEDs i have seen will not even take 4 volts). Here is the spec sheet for the XP-G, see page 4, lower graph.
http://www.cree.com/products/pdf/XLampXP-G.pdf
at 3.75 volts it is off the chart indicating there is a decent chance of breaking the LED by giving it that much voltage.

due to this narrow voltage range it is desired to use a constant current driver. that might imply somethign more specific than i mean but the idea is that you want somehting that will regulate how much current is getting ot the LED. it is unlikly that XP-G you're getting can take more than 3.75 volts but it is entirely possible that you ordered a driver/LED combination that can take an input of up to 18 volts.

whats the run time on a TK30?

Cree MC-E LED with lifespan of 50,000 hours • Uses two CR123A batteries or one 18650 rechargeable Battery • Uses four CR123A batteries or two 18650 rechargeable batteries (with extension tube) • Three sets of modes, two types of output for each mode , selected by turning the bezel (Patented) - Performance by using two CR123A batteries, the runtime will be longer by using one 18650 rechargeable battery Searching mode: Output A: 100 Lumens / 5 hours, Output B: 370 Lumens / 1 hours Camping mode: Output A: 12 Lumens / 30 hours, Output B: 175 Lumens / 2.7 hours Hunting mode: Output A: Strobe / 2 hours, Output B: 370 Lumens / 1 hours - Performance by using two 2500 mAh 18650 rechargeable Batteries. (with extension tube) Searching mode: Output A: 100 Lumens / 16 hours, Output B: 630 Lumens / 1.5 hours Camping mode: Output A: 12 Lumens / 90 hours, Output B: 175 Lumens / 8.4 hours Hunting mode: Output A: Strobe / 3 hours, Output B: 630 Lumens / 1.5 hours • Max beam length: 225 meters 300 meters (with extension tube) • Digitally regulated output - maintains constant brightness • Intelligent memory function • Working voltage: 3V~12
I think I use the 175 or 100 linens,love this light.