Oh bugger… I soldered it about 4-5 times and thought, that can I really suck this much in soldering? :weary:
Good thing is, I apparently don´t suck that much. Bad thing is, I don´t have the right resistors…
Any links where to purchase? Intl shipping mandatory…
Too bad for that mistake. SMD resistors are a problem, so many standards. Normally you would need a R22 or 220 (note the underline) for 0.22ohm. Not easy to find.
I just use a standard 1W pin resistor. A little big but fits just nice if you trim properly to size.
Ordered some standard ones. I first had even bogger in size resistor so I believe I can fit these ones also.
Now, again, for the wait…
I will just post this pic here, did it without pot and with relatively large (physical) resistor:
Please, use even more time than me to first bend those legs so, that they FIT and sit STILL easier.
Saves time, trust me.
Draws 1.49A dead :cowboy_hat_face:
I will paste it here, also:
If someone of you guys need a 0.22 Ohm resistor but don´t want to wait forever ordering from China or don´t have Electronics shop near you, PM me.
I can send some of those to you, probably won´t need all 20 anyway 
Someone have a Chinese source for these trim pots?
I only found these http://dx.com/p/3296w-trim-pot-trimmer-potentiometer-blue-30-piece-pack-133610 for cheap, but the smallest one begins with 100ohm so not much adjustspace like a smaller one, 1 turn probably more than 3 ohm…
I have ordered the light on the wallbuys promotion and don’t want to wait another two weeks when it has arrived. I have some 1/4W axial resistors on order with values below 1ohm but I think a pot would be my favorite.
This is what I ordered:
1 turn is only 0.7-0.8ohm. And how can be fine tune the current with this pot: http://www.youtube.com/embed/MRadYH5DSG8
I asked fasttech for stocking a 10 ohm trim pot, so we will see how that works.
I have exactly the blue dmm which you are using, too.
What are these dmm measuring?
The yellow dmm measures the input current, the blue the voltage, and above the lux meter measures the OTF lumen.
Viffer, thats a great vid and it tells a lot. But the gains seem very marginal considering the substantial current increase to gain a few extra lumens. Have you had a chance to play outside with it yet?
If we calculate the stock driver current which is 1A, the led current roughly 2A. The modified driver’s input current is 1.4A and the led current should be aroud 2.8A, but it’s probably not exactly true because of the driver efficiency loss.
According to the cree datasheet, from 2A to 2.8A led current increase results in about 25% brightness increase(at constant emitter temp!). 40% more current, and only 25% more brightness.
In our case the 40% more input current resulted only 17% more brightness. 1A -> 600lumen, 1.4A -> 700lumen.
The additional 8% (25-17) loss is probably due to the driver, and the higher emitter temperature.
I think it’s not bad for this price, but the zy-t08 is better in this price range.
Very similar beam profile as the other lights with big reflector, nice concentrated spot (measured 43kcd at 1.4A, 36kcd at 1A), but some rings are visible.
Do you have he crelant collimator head? I’m wondering what readings this light would get at 2.8a with that head
I’m waiting for my t13 to show up, have a few pots to try and a bunch of resistors if my pots wont work.
Got my christmas small sun zy-t13 today.
Here is my added resistor.
I don’t have measured current through LED, the wires seem a bit short and I am lazy…
The resistor is a 0,22R 5% TC50 MINI-MELF rated with 0.25W. Resistor get hot(Pres=4*0.22=0.88W, so about 0.3W per resistor on max current), but I have it now tested with just the head powered with a power supply for 30minutes.
Measured high input after mod with experimental power supply:
8V 1.4A. 11.2W
7.4V 1.55A. 11.7W
6.5V 1.79A 11.6W
6V 1.97A. 11.8W
On mid
8V 0.73A 5.8W
On Low
8V 0.16A 1.28W
10W is how I like my XMLs driven
So I took my new lamps for a walk and now I know why so many like this light.
I don’t really like the tailcap but the mode switch is nice and I love that it doesn’t have memory. It’s very nice and doesn’t need to hide before a 3T6, it throws more far than I can test…damn buildings!
For about 14$ what this has costed, its awesome!
10 ohm pots now on stock.
http://www.fasttech.com/products/1009/10000077/1224400
Fasttech is really awesome.
Now a How To guide would be nice for these “pots?” Including pics etc.
They look different from the other stuff shown here
A pot is just a variable resistor.
You use two beneath legs of pot as a resistor and then you can adjust with the screw on top the resistance and with that the current through the LED.
You should measure current with a DMM while adjusting like shown in the video above.
Nothing really complicated.
But since we have figured out which resistor is the way to go on this light, it’s easier to just solder a 0.22ohm in parallel. But if you want to try how more/less current behaves or if you want to know which value of resistor is the best for your personal mod. And since I never have the right resistor on hand I will order some pots for future mods.
So it doesn’t matter which leg goes where?
A pot is just a long conductor like a wire, the outer legs are the ends of this conductor, in this case between them is a resistance of 10 Ohm.
The middle leg is moveable over this conductor, and because a longer wire has more resistance as a shorter this causes a variable resistance between the outer leg and the middle leg.
Example:
Imagine a pot as a straight wire, with three different points of resistance measuring.
A—————B—————C. Between leg A and B there is a resistance of 5 Ohm
.
.
A———B———————C. Now there is between A and B 3 Ohm and between B and C 7Ohm
.
.
AB——————————C now there is no resistance between A and B and between B and C there are 10 Ohm
.
Between leg A and C there is forever the Value which is printed on the Pots case, here 10 Ohm. So you can cut one of the outer legs to get a variable resistor.
This is really easy and nothing really big, I think you will get it fast.
Thanks, dr zoidberg. 
That’s a very good and easy to understand explanations on pot.
