Going from 92% to 89% efficiency would be a third more heat off the driver btw
iām having strange issue with a buck driver, currently itās having 3x 0.24 ohm current sense resistors which means output should be 2.5Amps right ? but it outputs more than 2.5A when i try to run 3x osrsm white flat + 1x Xml leds in series.
iām powering the driver via motorcycle charging system ( driver is designed for it since itās from motorcycle auxiliary light) , input and output current hovers around 1.3/1.5 amps when motorcycle is idle @ 13.2-13.8v, but as soon as i increase RPM, voltage goes upto 14.2v , and led driver outputs more than 2.5Amps and goes upto 3.2Amps to leds. i get that when input voltage is not sufficient the driver wonāt output enough current to the leds, but when the input voltage is enough , it shouldnāt deliver more current than itās supposed to, right ?
now here comes the strange part, when i remove 1 xml led from above arrangement and run only 3 white flat leds in series, everything behaves normally, output current never goes above 2.51Amps.
any idea why running 4 leds in series instead of 3 , increases driver output current ? btw driver is designed to be used in 9-36v range.
thanks .
A little update, i tried running 4 leds in 2s2p arrangement, and driver output doesnāt go above 2.52Amps. so it works normally. but efficiency goes down. compared to 3 leds in series.
1. when driver is running 3x leds in series - input voltage*input current = 14.2v*2amp. =28.4w. ( output is 24w, so 84% efficiency )
2. when driver is running 4leds in 2s2p - input voltage*input current = 14.2v*2amp. =28.4w. ( output is 16w, so 56% efficiency )
i really want to run 4 leds, but not if efficiency is really that bad. with 4 leds i can use 4x 20mm tir optics, which will give more throw compared to 3 optics. 
slopegatri70, such driver does not seem to be able to handle 4 emitters in series with so low input voltage. For example, 4 white flat emitters in series require ā12.5V at 2.5A, plus any cable and connections overhead. The effective input voltage into the driver is just very little above that, if at all, and so it cannot work properly.
If you are adamant in driving 4S emitters with such driver, raising the input voltage may work. For that, get some DC/DC boost converter you can fed with the driver's input and then attach the boost converter's output into the driver's input. Suffice to say, adjust the boost converter's output voltage to a sufficiently high value, 14+V.
Actually the input voltage i checked was on driver itself ( 14.2v), charging system gives 14.4v so almost 0.2v drop. i canāt use any dc/dc boost converter because it will stll lower the efficiency. ( motorcycle generates 11.5amps of current, only 4-4.5 amps is left for auxiliary lights after i subtract power requirements of headlight/turn signals/pump/etc.
i really thought 14.2-12.5=1.7v would be enough for this driver. i guess itās not enough. maybe i should use 3 leds in series with 2x 20mm + 1x 26mm optics. it will have same or maybe a little bit more throw than 4s leds.
or maybe i should change the driver, but i donāt know if thereās any high quality efficient drivers available with low voltage drop.
man this experiment( modding the lights to reduce glare) is costing me alot, and thereās very little progress so far. (
I got also just from one German Guy 2 dead of those with 2R2
both with burned all in one switching chip
and it seems no one checks driver for not properly soldered parts, it is possible to let that do in a good PCB fab automatically
Did you meanā¦
I just got two of those drivers with 2R2 dead from a german guy, both with TPS61088 boost chip burned.
?
Without overclocking? Seriously?
@Nightsword: are rest of parts same or they have changed resistors too?
I donāt understand why smaller inductor causes eff drop. It can have lower DCR and higher Isat, take a look at specs from cheap inductors from ali:
I mean with inductor of same size and this one looks like itā¦
Eneenā¦
Same inductor size/series usually means there's an exchange between inductance and current handling among the different series parts, being all parts of the series usually equally priced. But it clearly isn't the same size/series, they downgraded the inductor, no need to be a hawk-eye to notice imho. They stepped down to a smaller inductor with the same current rating but less inductance. They saved on production costs, and made a worse driver. 
Series is different for sure, but they are pixel-perfect same size. This might looks like different current/sat specs or simply this driver has lower efficiency with smaller inductor. Bourns has good inductors (https://www.bourns.com/docs/Product-Datasheets/SRP1038A.pdf), I may give a try after ordering driver from KD.
BTW, is KD available? Iāve written some emails but no answer since weekā¦
The 2R2 is a little bit bigger as far as I can tell. I have one of 'em right here. According to my cheap 1/10mm accuracy Aneng caliper its measurements are ā10.25 Ć 10.25 Ć 3.7mm.
It's a bad choice what CDM has done. I may still go for it, but it is less appealing. And remember it lacks reverse polarity protection, so always stick it right. ;-)
Try sending some PM to Kaidomain's boss BanL. Or posting something here: KD (kaidomain): Deals and new products thread
They added a lot of vias. Strange that they would rework an existing design unless they were trying to address a problem.
Are these courses useful for understanding what are you talking about? Of course Iām not paying, money is reserved for more flashlights, LOL.
What about this one? Is it ok?
https://aliexpress.com/item/33000130006.html
That is Convoy XHP50 driver Eneen, good of course. Related technical information here: Damian's Testing boost drivers (#3+).
Nailed the best offers for the ā 22mm Manta Ray drivers here and there, btw.
Wow this convoy one is super efficient. It will surely go into my next build despite itās lacking hi 65% mode. Thx!
Thereās a new Convoy 22mm driver, XHP35 at 2.3 amps. Same controller as Loneoceans GXB172 so it should be easily configureable for 6 amp 6V, or just get a 12v mcpcb and resistor mod it.
https://www.aliexpress.com/item/4000046041955.html?spm=2114.12010612.8148356.9.27654e0dKFiR1y
hi is the driver the same in all of Malkoff drop-inās?.
I think Nichia M61 219B V3 single mode is a Buck driver right? - is this a new or an old buck updated driver or was there something else before this?. any reason for Malkoff not to get with the times, and update? -
I have read about malkoff using old tech electronics which could do with some updating. not sure.
I know the Malkoff is a reliable light, but is the driver reliable in 2019 too?.
kind thanks.
Iāve asked KD recently about the change - they didnāt change the picture so I charged them with not maching product description. Theyāve replied this change was necessary to implement thermal management option. They claim it has a temperature step down now.
Can anybody confirm? Deny?
Edit: just to be honest: as I understood KD explanation - the inductor change was necessary to maintain the same price after implementing temperature control. So in my understanding KD traded better inductor for temperature control.
So, downgrading the inductor was necessary to implement thermal 
management?
What a lie. 