Using the “shine flashlight thru a portable fan’s blades” method, I do not detect any PWM on the Convoy L2 (I have the older Silver version) — I think this is one of the few Convoys that do not use PWM for the lower brightness modes (unlike the Convoy S2+/C8 “old firmware” which has relatively slow PWM, or the new firmware Biscotti that also uses faster PWM; or I think even the Convoy L6 uses PWM for its lower modes)
I measured only around 2.4A tailcap current on High mode for my Convoy L2 (I got the warm-white 4500K tint XP-L Hi version) — mine appears a bit low compared to yours…
The sense resistors should be at the base of the black wire on the driver. This thread should be of use.
HKJ shared this photo:
I ordered a bunch of 0805 0.1R SMD resistors to stack. Stacking another R025 on top seemed to push towards 5.6A and make the driver very hot so we’ll see how far I can go.
I believe I have a dozen of 0805 0.1R resistors laying around from a similar mod I had done in my L6.
I might go the same route as you until my FET driver arrives!
The be reason you don’t see PWM is because there’s an inductor in between the switcher transformer and LED. the inductor stores energy in a magnetic field. The inductor dumps stored energy into the circuit when the transistor is off, filtering the power sent to the emitter. PWM is still there, PWM is always there.
It doesn’t make sense (to me) that a linear regulator would be used anywhere near a flashlight. Linear regulators are less efficient and run hotter. Linear regulators are more difficult to control digitally. With a switcher, the processor drives the power mosfet directly. Lower parts count, less heat, longer battery life. What’s not to like?
Thanks for the explanation!
(though I’m not sure I fully understand it…)
Anyway, so PWM is there but it’s not visible due to the inductor filtering the power sent to the emitter.
Pardon my next question, is this considered “good” or not that good?
Mine arrived today. Build quality of this light is great, I was extremely pleased with. The matte anodizing is very nice and itself provides quite a nice grip aside from the knurling.
Today I went ahead and stacked two R100 resistors on top of the R020 sense resistor.
The current was bumped to 3.5A which is quite convincing, yet nowhere near where I would like it to be
Yep that’s with bypasses.
By stacking the resistors I theoretically decreased the resistance by 25% and got 20% of actual current increase.
Keep in mind that the LD25 in my L2 came with an R020 resistor by default, not with an R025 like the LD29s.
Great review thank you. I am researching and learning for my second torch purchase. My first, Kinfire KO1B-T6, has convinced me these new-fangled LED torches are amazing.
So I’m thinking the new Convoy L2 Sand will make a more serious light and worthwhile upgrade for $36.99 plus 2 x 18650. Maybe a C8+ will be better for a beginner like me?
I do like more of a spreader and maybe I should make a white plastic diffuser for wide short range work.
An inductor is used in just about every switching regulator, and that’s a good thing. In a flashlight, the inductor is usually toriodal, it looks like a donut with wire wrapped around it. Every light in my (small-ish) collection uses an inductor to filter PWM pulses. the only lights I own that don’t use an inductor are a pair of Ultrafire XM-L zoomies I bought years ago, when I didn’t know any better.
It makes zero sense that this has an LD-25 or any other linear driver.
How are you powering it? 1s, or 2s? A linear driver would have to burn off ~50% of total power consumption (~10W) on high when powered by two LiIon batteries in series.
Either it has an LD-29 just like all the stock L2s over the last few years, just like it says on both the Bangood and Convoy product listings, or someone made a mistake during manufacturing and QA.
!