I’m only getting 2.6-2.7A on my XinTD SC-82 v4 with a QLite 8*380mA 7135 driver. My DMM is a Fluke and the leads are capable of > 3A measurements (DMM and leads rated up to 10A). I’ve made a small video of my testing procedure. Anybody see any mistakes I am making?
Everything seems in check, however the leads being capable of 3A is not how you should think about it, the direct drive will/could be higher when you will have short (1feet) and thick (12-14AWG) leads since less voltage is lost in the wires and the DMM.
Thanks for the quick reply Hikelite, I understand the DD would be higher with thicker/shorter cables. Unfortunately these are the only leads I have at hand. But since the Convoy with a 2.8A driver reads higher than the XinTD with a 3A driver (using the same leads), we should be able to conclude that the XinTD is underperforming.
Whats the likely culprit here? LED, driver? Has got to be the driver, right?
I think it it’s the steel spring. Try replacing it with a better quality one, or jumper it with some copper braid.
I also never use the thin probe tips when testing current.
The LED cannot be the problem for sure.
I'd say use short&thick leads to be 100% of the reading (spring is longer on the Xin V4). You can see that pressing the battery (compressing the spring) reduces resistance and current draw increases, the same when you measure with the very tip of leads, current is lower. Probably with thick and short you would not see a difference based on those.
Also, is your Convoy an XM-L or XM-L2? Any increased resistance will impact the current readings on the XM-L2 more than the XM-L due to the XM-L2's higher forward voltage.
I suppose that there also could be a bad 7135, but I would first get some shorter 18 AWG or larger leads on that DMM before coming to any conclusions.
Both lights are XML-2 U2. The convoy is a 1A tint and the XinTD a 1C tint, but that shouldn’t make any difference.
I’ll get my hands on some short and thick leads, to do some further testing. I am sceptical though. I am not an electrical engineer and my flashlight experience is limited, but it does seem that the leads are not the bottleneck. If they can supply the Convoy with 2.8A (which matches the driver spec exactely) with a gentle touch of the leads, then the 2.6.–2.7A for the XinTD look to me like they must be restricted by a weak link in the chain somewhere else.
You're correct, 1A to 1C tint shouldn't make any difference here. Since you are bypassing the tailcap it does look like the issue is with the driver or elsewhere.
You may see a 3A with 14AWG short leads, even if the other flashlight measured 2.8A.
I tried adding some copper braid (copper solder wick) and it didn’t make any difference. Then I tried replacing the spring with a Phosphor Bronze Spring from Convoy I happened to have, again no difference.
I took readings of all three modes and they all seem a bit low across the board compared to Foys XinTD SC-82 v4 review.
| Burggraben | Foy | |
| Low | 0.036 | 0.04 |
| Mid | 0.611 | 0.71 |
| High | 2.664 | 2.91 |
Since even the modes which require less ampere are lower it makes my layman brain think that there is no bottleneck anywhere. If a thin/damaged cable would limit the high mode amp then the mid and low should still match Foys values. They are all lower though, which a bad 7135 chip could explain. Thoughts?
The numbers do match up almost perfectly with what you would experience with one less 7135 chip.
If the steel is good can match the phosphor bronze's bronze resistance. I am not saying in this case, but theoretically.
I should not have doubted the experience of BLFers. A bunch of you suggested the leads are to blame and I just wouldn’t believe it because the Fluke leads were able to get a good 2.8A reading on the Convoy and a >3.6A reading in DD. I don’t have thick leads, but Buwuve suggested in a PM that I try a HiFi cable. As it happens I have really thick, really high quality HiFi cables around, so I cut a small piece and got the following readings:
| Burggraben Thick HiFi Cable Leads | Burggraben Fluke Leads | Foy | |
| Low | 0.056 | 0.036 | 0.04 |
| Mid | 0.807 | 0.611 | 0.71 |
| High | 3.020 | 2.664 | 2.91 |
Obviously my understanding of the flow of DC current is wrong, because I would not have thought that a thicker cable could pull even the Low and Mid reading up. In conclusion the XinTD SC-82 v4 is an awesome light and works as advertised.