Hello all,
I am planning on a 4.5a xm-l2 p60 build (yeah, I know it’s irresponsible 
>) ) and I have everything but the driver, which I’m still waiting on. My question is, does anyone know how much current the l2n tailcap can handle? I really don’t want to blow the switch. If 4.5a is too much, is there another switch that will work?
Lighthound carries a $7 McClicky switch that isn’t at all difficult to swap into the Solarforce tailcap. That should be good up to around 6A, even though it’s rated at 3A. Widely used, I have about 7 of them in my own Solarforce lights. 
Edit: the stock switch may work for a while, but eventually you’ll find the battery rattling and the spring discolored and sagged. Might even break connection on ya at a bad time. Solder a copper wire or copper braid into the spring to bypass it and you should be good at that amperage.
Where is a good place to buy copper braid, and how wide should it be?
I just use the silicone insulated wire that I use to upgrade the wiring in the light, put a bit of a coil to it so that it compresses inside the spring when the spring takes a load. It carries the current, the spring does the pushing, works all around. I find, for me, the braid usually has flux in it and will suck the solder too far down, making it stiff then breaking when the spring get’s compressed. Much easier for me using wire. I leave the insulation on it for the springiness, usually 22ga, and solder it inside. Had good luck with that so far.
I have run my solarforce switches up to 4.5 amps, they have not failed… although they may be limiting current.
I also have swapped a number of stock SF switches to a mcclicky switch which handles current better
I have run mcclickys at 7-8 amps all with good results.
Thanks for the responses! I’m going to try the copper wire idea.
Almost anybody doing a flashlight mod bypasses the spring. Basic flashlight modding 101. By taking the current, and therefore the heat, out of the spring you gain amperage to the led and have a more solid system.