1,500 lumens with 4x XM-L2 not heavy gauge wire or spring mods just 3x king kongs. Spring mods and heavy wire would bring this up to 2,000 lumens easy and have great run time too.
3,000 lumens with 2S2P XM-L2 still no heavy wire or spring mods but with only 2x king kongs. I didn’t try it with 3x king kongs because I don’t have them re-flowed onto sinkpads yet but I am guessing they could handle it pretty well once I do.
This is in one of the lights that look like the typical trustfire 9x or 12x only it’s a kingfire K34F.
I would combine RaceR86's HX-1175b and Jerommel's 2S2P ideas. Use 1206 sized resistors if you change the current. The heat seems to be comming from the voltage sense resistors. I think 12 amps and beyond is fine if you pot. Here's an easy, reversible, and cheap potting recipe.
Keep in mind that I switched the FET's out on my HX-1175b. Not sure if it is critical to keeping the heat down at 12 amps or not. Relic reported the stock FET's get hot. Comfy's FET's don't.
If you have room and can convert the cells to parallel, and the LED's can be wired separately, you could use qlite drivers in master-slave configuration.
