Oh man. I hope my Trustfire J12 from DX is genuine. Worried about buying from them now having heard they sell fakes. Was looking at getting the TF 26650's from them as well after reading benckie's test.
My tailcap reading for the J12 using a $15 multimeter and fully charged protected NCR18650A 3100mAh shows about 5.50A for 2 cells and 2.35A for 3 cells. Does that make any sense at all?
All ive seen of the Trustfire 7 x T6 looks to be fake IMO.
ShopBot the cells i tested where from manafont not DX, just because mine test well from manafont does not mean you will get the same results from another seller........
The TR-J12 readings are about right mine reads higher or lower depending on the cells and there charger rate, its best to test the tail cap readings when the batteries are fully charged.
Sounds good, true accuacty depends on the voltage level of the cells, the leads and DMM. (and a host of other things)
Yeah I noticed that. Was about to just buy a pair from DX, but heard of them selling fakes. So I will think about it...
I think 5 X T6 is enough~
I won't buy TrustFire 7xT6！
Aloha and welcome to BLF sintro & summerfangfan!
If you could fit this driver in it youd have a monster for just a $20 investment! ;)
It's good to have you here, summerfangfan.
After having used this torch for 30 minutes on high mode it is even not warm. Is this good? There should be more power in it.
If it is a fake I don't know I bought it at Lightmalls. Com
Cars maybe, but engines are most efficient at wide open throttle. The problem is that you can only have so much load at a certain air/fuel ratio before you need to richen it up to prevent detonation and preignition. In most vehicles, the best fuel economy will be where you get up to a higher speed while at a stoichiometric mixture, then coast down in speed a little with the engine off, then repeat.
Aaaanyway, bad analogy :p
What about this one
7 x T6
MarsFire B Cree T6 5000-Lumen 5-Mode 7-LED Flashlight - Black (3*26650/2*26650)
Well I can confirm that this flashlight is not worth the money. It actually gets less runtime, runs hotter, and is less bright, than my trustfire TR-3T6!
I was hoping it would be more efficient at least.
I definitely think it is a fake. Not Trustfire for sure.
Update: confirmed my flashlight is a fake. Bought from Lightmalls.com
Buyer Beware!!
Cars are most efficient at the crossing point of engine efficiency with air resistance. If it were just an engine turning a crank, it would be a completely different story, but that whole wind resistance and transmission gearing things really screw it up. Wind/Air resistance is exponential with speed - it's not just double from 20 to 40 mph.
PPtk
First of all, PilotPTK is definitely correct about the trade-off between air resistance and drive train efficiency - and also the exponential increase in force from air resistance (relative to speed increase). That's a good part of the reason that the Toyota Prius used to have (may still have) better mileage in the city with stop-and-go driving vs constant highway speeds (because of the greater air resistance). The Prius is able to recover the energy used in stop and go driving because it generates electricity by stopping - rather than just producing heat.
BUT!..... Sintro says "But back, to the flashlights! As long as you have the same amount of power going to something, whether it be 1 18650 going to 1 xml, or 1 18650 going to 10 xmls, it won't matter, you should theoretically get the same brightness..... [and so on].
I don't mean to offend but this is patently untrue. There are several other important variables. Take for example the driver being used. Those can make a huge difference in brightness. Also consider the efficiency curve of the led (see the graph referred to above). Then consider the reflector efficiency (something that Sintro did allude to). And how about the lens transmttence factor, and so on, and so on.
Regards, Bob (KumaBear)
P.S. Voltage is not power. E=IR Power equals current times resistance. Remember the pipe analogy. The pressure is roughly equivalent to voltage but the energy transmitted depends both on pressure and capacity of the conduit (the pipe).
so......
ditch that driver!
and while you've got it apart, make sure the LEDs are properly mounted (ie not a 2mm layer of fujik between star and mounting surface)
you at least got a big hunk of aluminum, reflector, leds, switch, etc. - performance might be disappointing, but i'm sure it can be made into a good light 
After reading a few comments I am sure I got a fake. I try to get a refund from Lightmalls. We will see what happens. Don't buy from Lightmalls other people got also fakes.
I'm not sure if it's correct if I put into this way. If each of the single XML of both of the 7*XML and 5*XML Trustfire are equally powered, I think the throw ability (lux) between them should not be too much different. While each of the individual reflectors are being smaller for the 7*XML, however the additional 2*XML will pump out more lumens and adding some kind of more brute force for throw.
Nooooooooooo! I also place an order for the Trustfire TR-J18 over at lightmalls an its almost getting here. Could the people who got fakes please upload a pic on here, or could you please provide a direct link to the product you got so i could confirm its the same one i got please.
The original post was not of a trustfire TR-J18 but of a difference fake trustfire with 7 x xml's with a different lay out, but in saying that there is a lot of fake trustfire lights going around and around, i believe a lot of people brought fake TR-J12,s and TR-3T6's IMO