Alright that chart looks good. Thanks! Since the driver side seems to be ok, how about the LED side? is that hunk of copper + aluminum fins + mini fan good enough to cool 5 amps?
It depends on how it's put together. That's not how I would do it, I'd use just enough copper to disperse the heat into the aluminum, and then as many aluminum fins as close to the LED as I could get. Copper moves heat well, but sucks at dumping it to the ambient air. Aluminum is just the opposite (mostly). The majority of that big piece of copper isn't doing anything to dump the heat, it could end up just storing it (i.e., a 'sink' with a blocked drain).
And be careful until/unless you get a true direct-copper star in there. That one's not fundamentally better performing than a plain aluminum star.
Using a non direct star you shouldn’t go much over 3A especially considering you say that’s your only emitter. Best would be to get a direct path star ASAP but since that is a copper board you could use a knife and cut off the thermal layer below the thermal pad then fill it with solder and re reflow the emitter back on, that way you had a direct part.
I have a 2S light running an MT-G2 very nicely, but the voltage overhead between your cells and the Vf of your led does limit the amount of current you are going to max out at.
Check out the graph at the top of page seven in this pdf:
I’ve heard that each 7135 chip needs .12 volts, so if we decide that we want to drive an MT-G2 at about three amps, we need 8 of the 380ma spec 7135’s. 8 * .12v = .96 or about a volt. If we go back to that chart from above we only need 6.15 volts for the led + 1 volt for the 7135’s to get an MT-G2 to 3 amps, and with a 2S setup let’s say we start out at 8 volts we’re going to get some runtime before the light starts to dim due to a lack of enough voltage overhead. Definitely not going to get much more than 3 amps, but it does work.
At some point, adding more chips won’t make the highest mode any brighter, it’ll just bleed energy out of the driver, and annoyingly make the lower modes brighter as they’re just percentages of the highest output all the chips could theoretically provide assuming you had enough voltage overhead.
With five cells 5A shouldn’t be a problem but you will smoke the led if it’s not either on a direct bonded copper star or one with solid copper wire drilled and pressed into the center pad. Hot melt glue is neat stuff but this isn’t the correct application. JB weld or some other high temp adhesive would be better. With the driver located away from the led it should be ok but it wouldn’t hurt to have some copper or aluminum bonded directly to the chips to wick away heat.