Do anybody know temperatures Convoy S2+ XML2 T6 when used 7135*4 (1400mA) or 7135*6 (2100mA)
Interested high mode
Thank you.
I had a 7135*4 one and tailstand ceiling bounce for hours it got never uncomfortable hot, so around 50dC
It will be fine with stock sluminum star
7135*8 with DTP star gets too hot to touch 80dC but the LED junction temperature does not get to a critical level
I made the mistake of tailstanding an S2+ with 8×7135 for maybe 5-10min, and it was literally too hot to touch, let alone hold.
Had to very quickly grab the body with a wad of tissues and press the switch to turn it off, then even after another few min couldn’t even pick it up by the pocket-clip. Needed a loooong time to cool down enough for me to be able to hold it.
Impressed me as to how well the entire case conducts heat, though. Damned thing was like a curling iron… with no handle.
If aluminum gets over 70dC you burn your skin
The Cree LEDs can handle 150dC junction temperature
And with a DTP star you get about 40-50dC difference to the body
So even boiling water on a DTP S2+ wont mean that the LED gets in the danger zone desoldering itself
I put a qlite 7135x8 driver in mine with the guppydrv. Besides the 22 different modes you can choose, it has an adjustable turbo timer. Just set it to what you want and it will ramp down smoothly to 50%. No worries about over heating. 
I’m curious what the real runtime numbers are on a 4 x7135 light run on high vs a 8x7135 light running at 50% is ….? how much more efficient is it really ? Like 3 hours of runtime vs. 4 ?
Phlogiston has measured the light output of different tints with 3*7135 to 8*7135 at different modes.
The assumption is that a 4*7135 in all modes has half the current of an 8*7135.
Maukka has measured the runtime of his 8*7135 in med mode (40% current) at 4 hours 20 minutes.
I have not found a runtime measurement for the 4*7135 at med mode but I would guess it would be twice that of a 8*7135 or better.
I am curious what the runtime of a 4x7135 on high …VS. a 8x7135 on medium or 50%…whatever is the equivalent … amp and a half . I know the 4x driver will be longer …Question is how much longer ?
Why do you think the 4x will run longer? If the load on the light is the same, 1.4 amps, the batteries will last the same. Driver efficiency is good on a 7135 design. Got to be less than 2% difference.
Are you asking because of curiosity or do you want max runtime?
The question boils down to whether pwm pulses that have the same average current as non pwm actually affect how much current csn be drawn from a cell. It might be inconsequential or it might not or there might be other effects of the difference as well. I’m curious enough to want to to know even if it doesn’t change which method I choose.
XML2 U2 efficiency
Current / Lumens / lumens/W / lumens per ampere
For 1.4A Tj=60dC 566 lumens 132.8l/W 407.7l/A
For 2.8A Tj=75dC 909 lumens 99.3l/W 324.7l/A
If PWM the 2.8A the junction temperature will be for both drivers the same
We were talking about the efficiency of the driver, not the emmiter.
2.8A driver will have less losses as the voltage drop is lower as the diodes voltage is a bit higher
But in a light that has no buck or boost driver the efficiency of the driver does not matter, it is a linear driver which heats the voltage overhead from battery
What’s the max lumen for the 7135*4 at 1.4A on biscotti?
It will vary based on the particular led, but probably between 450 and 500 lumen.
The thread I mentioned in #2 starts with a list of all S2+ modes, currents and lumen outputs for all XM-L2 tints.