Basically, but not exactly, yes.
I mean that LED drivers ( well, correctly built led drivers ) are controlled by/for output current ( through sense resistor ). Actual voltage is only a consequence.
But there can be some safety functions on output like overvoltage protection ( not important for buck drivers ) or LED fault protection ( undervoltage / shortcut protection - not important again for buck drivers ).
Or maybe the current sense resistor is a high side type and the feedback pin of the controller can only work on a higher voltage interval.
What ever they use in These I removed 2 of the 4 stack of resistors to drop the output down to about 4amps, changed the lens for one with a much shorter FL then mistakenly fitted the 3v 50.2
There are not many information available about the technical details of the lamp. :confounded:
Was there an old style toroid inductor driver in it, or a high frequency with a shielded SMD one?
Yeah, toroid drivers generally runs on low frequency resulting terrible flickering. I experienced that.
The 4.5A You linked is a 2 group driver, like the one I want to replace. This one has higher current, though. But in the lowest mode it always blinks 1 time as waiting for group change command. Annoying.
I think I will make a try with the Manta Ray driver. In the worst case I flushed 9 bucks. :partying_face:
And you're saying I removed 2 of the 4 stack of resistors to drop the output down to about 4amps, are you serious? Because if so, the driver must be a big buck driver. 8 amps in a 2S buck driver is nice, could you please share photos of it? No rush, of course, but take the oportunity to reset the sense resistors (lower it even further LoL), a 3V XHP50 can take that. And we will see if the driver can take the heat. ;-)
No need to feel ashamed or guilty for anything, its our creation so better learn from the experience.
I've taken a look at the video from the ad, looks like its long-necked so long stock focal lenght. Since you changed its lens now it must over-focus, doesn't it?
If the driver is good and the emitter is well heatsinked, it may be a good host after all.
Yes stock lens focus right at furthest point from emitter, with alternative lens prime focus is half way instead so a good 50% closer to emitter, but yes will over focus if you move it out to far, in all honesty with a genuine XHP50.2 fitted it puts out a reasonable amount of light
Heatsink is not great , the head is not connected to the body it slides forward/backward on the body so that large heatsink is basically just for show and does not aid cooling, the metal is quite thin even with current reduced to 4A it still heats up pretty fast
Perhaps 2k lumens is more truthful stock figure, the Fake XHP70ās do put out fair power
The driver has arrived.
I made a quick test just before feedback the order.
It works well with 3V XHP50.2, although the coil tends to whine softly in high and turbo. To be honest, it was just a really quick test, I used a cheap adjustable buck power supply with quite long wires and crocodile clip connections, and it seemed that better clamping decreases the buzz. So the final installation can be better in terms of noise.
Mmm, so you used the 1S/3V emitter hack because you intended to use the driver for long periods on high, isn't it Lacerta?
My 6V XHP50 ā4A SK98 does good, but its heat path is enhanced and I certainly don't keep it on high for long periods and never out of my hands. On the other hand a triple Sofirn C8F on high with a mid-power 18650 will burn your hand way before its 2m 30s step down if you keep it tail standing. ;-)
I am not a big fan of short lasting turbo levels. :laughing:
Basically the host can handle ~1500 lumens from an XHP50.2 continuously, so the high of this driver with ~1400lm is good, and the turbo is ~2000lm and can be activated separately. This one also have good mode spacing.
Moreover, 6V output buck drivers cannot hold constant current through the whole 2S battery capacity range in high levels, considering the 6V emitter Vf, the battery voltage, and the driver maximum output voltage ( which is ~Vin-0.3V in the best case ).
Finally I started to rebuild the host. And also I made some further tests with better wiring.
The first 3 levels are good. Input values are showing constant output values which are corresponding to the specs. With the 3V XH50.2 50mA, 150mA, and 750mA. For 6V led 100mA, 300mA and 1500mA is specified.
But at high and turbo levelā¦ The driver seems to get mad. :person_facepalming:
The input current should be around ~1.6 and 2.4A.
But itās 3.4A at high and 4.5A at turbo! And the inductor is whining like hell. Seems that the regulation is not working properly at higher levels at the increased Vin/Vout ratio. :cry:
I wonder whether the replacement of the inductor would help this? Currently a 4.7uH is installed.