How could this be done? It’s a good and useful idea, but I have too little imagination doing something comfortable and functional when you have to change batteries to charge them often.
Alex,I had posted an idea like this for parallel battery carrier,so I'm on the same page but I feel time and cost to do so would not work out.Maybe using a dummy 18650 would be a better solution,it would allow the use of a 7135 driver with custom programming.
That’s not what I wanted to hear…. I ’m still waiting on mine, I ordered it and a UF-2220 on 7/15 I wonder how the ZY-T16 will do against my Shadow TC500??
I have already done that parallel battery mod before, depending on the diameter of the tube just use desoldering braid and kapton tape, I’ll see if I have a pic of the setup
side by side comparison, left ZY-T13, right skyray A0 ebay clone
driver, 23mm diameter as the guy wrote
a simple resistor mod could improve the output
what value resistors would be adequate to increase current to 3 amps? would you need to change 1 or the 2 resistors? could you post a link to the review please?
As you see there are 2pcs R22 (0.22ohm) resistor on the driver wired in parallel, I think these are the current sense resistors. Just simple solder a 0.3~0.5ohm resistor parallel with them, and the current will increase.
I was just about to leave the house when I saw a yellow envelope from Manfont had arrived. Here’s a very quick review, then I’m off to the store…
Draw at the tail on high: 1-cell: 400mA, 2-cells: 1.1A.
Quick conclusion: as a two cell light, the driver can stay or be modded, but as a one cell, it’s got to go.
Driver has annoyingly long lasting memory that goes to next mode at next power-on. Will have to ask Viffer where to put a resistor to bleed out the memory in 3 seconds or less.
Side by side with HD2010, both on high, two cells in the ZY-T16: The HD2010 blows it away. It’s about twice as bright. Beam profiles are almost identical. Perhaps the ZY-T16 has a slightly larger spot, but I haven’t experimented with the focus yet. Reflectors look the same.
Fit and finish: Anno is glossy, which to me, appears cheaper than matte, but that’s a personal opinion. The anno on the extension tube is slightly lighter in color than everything else, as if it came from a different batch. Laser etched logos are slightly askew like a poorly hung picture frame. The “strike” bezel is not stainless steel as photos might suggest, but at least with clear anno intead of black, chips won’t stand out.
Gotta go!
@viffer, can I find some 0,3-0,5ohm resistors on some cheaper flashjlight drivers. How to recogniese them?
Have you done that mod and what was the result??
Popped out the driver on the ZY-T16 and measured Io with a clamp meter. With 880mAh draw on two cells, only 1.1A was hitting the LED. The driver is terribly inefficient. I added first one and then a second 0.20 ohm resistor and power output only climbed to 1.3A. The driver had to go.
The problem… the cavity for the driver is very shallow. Every other high power driver I’ve used was too tall to fit, with the exception of the DX 20330, which was too wide to fit. Luckily, I had one laying around that I bought to experiment with and it worked out pretty well. The driver is DX sku 106805. It is incorrectly advertised as being only 17mm in diameter, when in fact it is ~22mm wide. With the addition of a brass ring, I was able to adapt it to fit into the slightly wider driver cavity of the ZY-T16. On high, my clamp meter measured 2.3A to the LED when the driver is fed by two cells. It will not operate as a one cell driver. I added a 0.47 Ohm resistor to the stock resistors and this pulled output to the LED up to 2.7A on high while pulling 1.33A from the cells.
The mode sequence is not ideal (mid-low-high-strobe-sos), and it takes much longer than I prefer for the memory to bleed out (a few minutes it seems), and the light is now two-cell only, but… finally, with this modded replacement driver, it is as bright as the HD2010.
Hi Techjunkie, I just got the DX driver too (106805), and was wondering how to reduce the output current by a sense resistor mod.
I’m not so sure which one to swap, and to what value as well. Could you be so kind to take a pic where you modded the resistor? Thanks!
If I want to change the output current to 1.8A, what value should I change the resistor to?
Cheers! 
I still not got mine :cry:
Hey there ryansoh3, it's a pleasure to have you onboard!
Nice cat! ;)
Thanks for the warm welcome.
Did you find me on LPF? What’s your username?
Cheers! 
Sorry for the trickery, I'm not on LPF.
I did an image search for "ryansoh3" and a lot of pics from laserpointerforums showed up. Just about the only picture that was actually yours was your avatar. I like to post a relevant or humorous image that I find on the web every now and then. Thanks for joining BLF. :bigsmile:
Haha, yeah I was pleasantly surprised to see my avatar on LPF.
Anyways, I’ve been a lurker around here for sometime. I love the good info that’s in BLF about nice lights that won’t empty your pockets.
Cheers!
Now that was the understatement of the year, rc. 8)
Sorry, I didn’t snap any pics of the driver, and I don’t remember the resistor values of the two sense resistors that are installed in parallel. You can see the first one under the coil (0.1 Ohm labeled R10) in the DX stock photo, here:
You have to bend the coil up to gain access to the two parallel sense resistors on that top board.
To lower the output current on high, remove that first resistor (or the 2nd, it doesn’t matter) and replace it with a slightly higher valued one.
If two or more resistors are installed in parallel, here’s how to calculate the total value of all those resistors in parallel (you need to know this value if you wish to calculate which values to use for different output currents):
Rtot = 1/(1/R1 + 1/R2 + … + 1/Rn)
For example, if the other resistor that you can’t see is labeled R20 (0.20 ohm value), then the total value of that and the R10 in parallel is:
1/(1/0.1 + 1/0.2), which equals 0.067 ohm. As you can see, the tolerances you are working with here to change the drive current are incredibly small.
For the moment, let’s assume that the other resistor is also an R10. That makes the actual total value 0.05ohm.
Given the 2.3A clamp meter measured output of the board with the stock 0.05 ohm sense resistor value, we can calculate that the operating voltage used to control output at 2.3A*0.05ohm = 0.115V. Let it be known that the resolution on my clamp meter is not that small and is only accurate to .1A give or take 0.5A. For better accuracy, I could have used an in-line DMM, but wasn’t that concerned because I was fully expecting the driver to not perform this well.
Here’s how I calculate the sense resistor value needed to achieve a different drive current, by keeping that voltage value the same as above…
0.115v/x = desired drive current.
In the case of 1.8A drive current and 0.05 total sense resistor value, the equation is:
0.115/x= 1.8A OR 0.115/1.8=x
so x = 0.0639 ohm is the target sense resistor value desired to drive at 1.8A on high.
To change 0.05 ohm to 0.0639ohm, refer to the resistors in parallel calculation above.
Checking my math above, if the values I have guessed at for the stock resistors are correct, and the clamp meter was deadly accurate (both unlikely), then the sense voltage value is 0.115 and the sense resistor value required for 2.7A would be 0.426 ohm. Clearly, something is off a bit, because, adding an R47 to two R10s yields a sense resistor value of 0.452 and .115/.452 is only 2.54A.
Knowing all the calculations helps to set you off in the right direction for selecting sense resistor values to experiment with, but in the end, the tolerances are so tiny and the measurements have to be so accurate, that the solder itself can sway things in any direction. In the end, you have to experiment a little bit and be willing to accept a margin of error of ~0.2A, or you’ll spend all day soldering and desoldering smd components the size of fleas.
Thank you very very much for your explanation. The one I got was slightly different than the one I got on DX. Here’s a picture:
As you can see, the resistors are a bit different. However, I followed your instructions and everything seemed to work out very well.
Tomorrow, I just need to get myself a 0.112 Ohm SMD resistor and soldering it on the place of the R200 resistor.
Do you have any tips on soldering microscopic SMD parts? It looks darn hard to accomplish, and I’m not good on soldering normal circuit boards in the first place.
Again, thanks a lot for the helpful explanation. Appreciate it.
Cheers!
If you replace the 0.20 ohm resistor with a 0.11 ohm resistor, the output current will go up, not down. (reducing the sense resistor value increases output current).
I thought you wanted 1.8A out (less than the default)…
By the way, looking at your pic confirms what I suspected, which is that there were no R10 on my board either. In fact, I think I also had an R20 and an R15. That means that the OEM sense resistance value is 0.086 Ohms and with a 2.3A drive current, the sense voltage was 0.197V. To output 2.7A, I’d have had to drop the resistance to 0.0730 Ohm. By adding a .47 to the .2 and .15, I’d effectively dropped it to 0.0725, so the numbers all gel nicely. If your board performs the same as mine with the same values, then to lower output to 1.8A max, you’d have to change the sense resistor value to 0.109 Ohm. To achieve that, you could remove both the R15 and the R20 and replace them both with a single R10.
My method for replacing these resistors is not ideal - I use a 30W iron with a broad tip that spans from edge to edge of the resistor, and a pair of forceps to position the resistor and keep it from sticking to the iron when I pull it away. It’s very delicate and very frustrating work. A better way to mount them would be with solder paste and a heat gun. The paste I have (for reflowing LEDs in a pan) but the gun I do not.