Whats the difference in brightness between 7135*8 and 7135*4?
I agree and my choice would always be the brightest. I’m just afraid that running it on turbo all the time will damage the LED.
The 2800mah version is about .15 or so a on low, 1.5a on medium and 2.8a on high (As assumed). It looks good and I don’t plan on having issues if I need to run it at 2.8a on a bike but it’s just not that practical for most uses as it gets too hot and runs down quickly.
1.5a is good for average use however it’s still almost like a spotlight; even on low I don’t think that it’s really that dim. I do have a feeling that the reflector has lost me some lumens too when compared to my SMO P60 and XinTXV3 U2’s (All of them U2) but it is much floodier with a wider hot spot. I could have just lost the tint lottery with it too. It’s not bad though and for $14 it’s a heck of a pocket rocket that I’m not afraid to carry and show off.
You can always remove chips though, and I might end up doing that in a while to make it more useable since I’m building up more 2.8a nanjgs anyways. BTW the 2.8a and 2.1a (AMC8-6) drivers are the 105c while I believe the AMC4-3 are the 101-AK Nanjg.
This means that you’ll have a larger cushier spring on the 101-AK’s and a shorter stiffer one on the 105’s; if you run unprotected cells in the 105c then you’ll have to use a spacer or remove the insulator for the tail-cap or it’ll be too short.
I never had a LED burn through, it was always the driver which gave up first. I went for the 1.4 Amp version (4x) which is already streching it for me thermally and I'm not into turbo modes. The 1.4 A model has also the better mode spacing with a 30% medium.
Cree’s XM-L datasheet lists 150C as the maximum junction temperature. I’m measuring the temperature of the body of the flashlight. To work back from body temp to junction temp, you’d have to know the thermal resistance, which I don’t have a way to determine.
I fall into that category. I would go with the 2800mah version. Since the medium is 1.5amps it is, IMO, the perfect combination of heat/light for an XM-L.
Ideally i would get the 2.8A and program custom modes. Since i don’t have that ability, i would consider the 2.1 or 2.4A (unfortunately). The medium is just not where i want it on the 2.8A
LEDs are cheap, so don’t worry about burning it out.
I figured I’d be the odd man out. 
Let me tell you a cautionary tale. Years ago, a certain flashaholic made his way to his bed and fell into a deep sleep (alcohol may have been involved.) In his pocket was a Surefire L4, which somehow got switched on. Surrounded by clothing and bedding, an aluminum light with a 5W Luxeon can get pretty warm. By the time the “ouch” signals from his nerve endings managed to hit the on button of our hero’s cortex, he had a interestingly shaped burn on his leg that took forever to heal.
Not that any member of this forum is likely to find themselves in similar circumstances, of course. 
You know the story ..
She eats the porage .. too hot 2.8 /// the other is too cold ..1.5 .... Than she eats the babies porage at 2.1 and it's perfect .. if you want ..you can add 7135 chips to it later
get the 5C tint too ~!!! it's very nice :)
What he said^
And I have the 2.8
I guess not every battery is able to provide 2.8 amps if partially depleted. Then there will be a decrease in brigthness even on low and medium as they are just pwm-dimmed high. You may end up having a 8*735 light for the first 20 minutes and a 6*7135 one for the rest of the time. I saw this happen to 7*7135 light (Shadow jm07) running on panasonic 3400s.
Just received the Convoy S3 recently, 2.8 is the way to go. I clocked mine on Medium at 1.3A which is basically 7135 x 4 chips, so why not give yourself the best of both worlds? Use 2.8A for fun, when it gets hot turn it down, simples.
Tube lights this size are still plenty bright at 1.3A, that’s around what most premium tube lights put out. 2.8A is noticeably brighter, say on appearance 20% to the eye and great to have when you want to blast some lumens and feel how hot the little pocket rocket gets.
I’ve got Convoy S3 and M2 host on order after assembling the C20 Cree host with an 8*AMC7135 and XM-L T5-5C1 emitter and liking the result. It gets real hot if there is no active cooling, but the other night when descending a mountain at –7c with active cooling from a slight breeze it stayed about room temperature even when left on for 15-20 minutes on highest setting. I also have used a123 LiFePO4 18650’s in it and on high they last for 50 minutes with not as much heat and decent output. I’m expecting a bit better cooling with the M2 host, but for me the prescribed use of the 8* driver on high will be handlebar or helmet mount when there is some sort of active cooling, and the rest of the time on low or medium and pay the price of less efficient driver at those modes.
im gonna place an order at fasttech soon. been wanting another tube light.
is the 2.8 amp s3 brighter than the xiachaio? anyone have both
Is there a link for the “xiachaio”?
I have the XIAOZHI (not sure if it is similar to the xiachaio?), it has the 7135*5 driver, FT SKU 1240400, got it at the same time as the C20 Host. Do not like it as much. The light is much higher in tint, probably about 6500K, gets just as hot as the C20 (but seems almost as bright as well), and sometimes the double O rings prevent the tail cap from screwing on properly.
They use the same kind of drivers so there would be no difference in brightness, it just depends on the level of driver you choose.
yes the xiaozhi was the one i was talking about. i thought the xiaozhi was running at 2.5amps?
so you prefer the s3 over the xiaozhi because of the better tint. could you tell which one is brighter and floodier? i only want one more tube light and cant buy both.
From a dealer website:
Xiaozhi:
C20:
I’m debating with the same “how many AMC7135’s” question for Convoy S2 or S6.
Can anyone tell if there’s any notable efficiency (or other) differences when running 8xAMC7135 at 50% vs 4xAMC7135 at 100% mode?