So I just reflowed an Xp-G2 onto a copper Sinkpad My plan is to drive it hard with the sinkpad screwed to either aluminum or more copper. Currently it’s screwed to my big bench heatsink for some testing. I would like to take it to around 4 amps, however testing with two 18650’s in parallel i can’t get it over 2.5 amps. The driver is a regular 5 mode 8x7135. Even direct drive I can’t get any more out of it. Any ideas why?
Your cells sag too much. You either have to use two cells in series and a buck regulator or really good cells.
I just tried 2 cells in series with one of those cheap buck boost multi emitter drivers. got a solid 3.8 amps and it never dropped when it got warm.
Nevermind more like I just melted the snot out of the driver after about 3 minutes.
Sounds like the driver is doing exactly what it’s supposed to do, regulating the current. 8 x 300 mA per ’7135 -> 2.4A total current.
8*350 for Nanjg or 8*380 for KD V2 should be 2.8 - 3.04A. Also, he said he didnt get more on DD.
3.8A from a 2cell buck driver means probably ~ 2A or a bit more from each cell. Are they protected cells that have a current limit? The led isn’t able to limit current. If the voltage is high enough the current should just keep climbing.
Well I connected it to my accucell six, set it to 4A and let it go. Had 3.9A on my meter and 4.0 on the accucell. Voltage reading on the screen of the charger was reading 4.3 volts.
I seemed to work for a while then a giant spark came from the die, now it’s black and no longer produces light 
The first reflow onto copper I did was a bit of a damp squib as it didnt want to be driven hard, even DD it never pulled more than 1.8A! Changed the led and was a bit more careful with the heat and bingo….as much current as I dare!
Why do you think that happens?
have similar problem xpg2 on copper around 2amps user nanj 105 and direct direct drive with AW IMR cells.and in normal pcbs i can take 4 ,something goes wrong with the reflowing…also with xml,xml2 i dont go more than 3 amps again reflowed on sinkpads.
edit
i re-reflowed the led this time by pressing the led down so the extra solder leave and got better results.