Simple review of the KD 1-mode 3-18V driver

Flashlight Modding and DIY Parts
1

Just wanted to share my findings with the driver found in this drop-in.
This is not a very in depth review. It does lack some important measurements, but I believe it gives a fairly good picture of the driver.

Out of the P60

Close up

Here are some tail cap readings I did not long after I got it.

(battery voltage is not measured under load. These measurements were done with the P60, so in combination with XM-L2)

As you can see, its quite useless below 3,7V. Seems to be a 3,6-18V driver too me. Once again, KD messes up facts.

I measured amps to the emitter yesterday. Started out with a battery pack. Barely used eneloops that was charged around 2 weeks ago.
Emitter: XPG2 on copper.

1,5A to emitter
Im pretty sure I tested it with 3 batteries too. And saw about 1,5A (but not 100% certain when writing this)

Changed to powersupply (5-15V)

5V


6V


7,5V


9V


12V


15V

That gives me these numbers in the middle column below. I did the test once more with 22 AWG wires. Still same results. The small differences are most likely me not setting the power supply on precicely the same setting. (as pictures show, its only a scew, not a digital display with output value)

People are free to draw their own conclusions. Many people here have way more knowledge than me.

My thoughts:
Based on the numbers I would say its a mediocre if you are only using 1-lion. 2,1A input. About 1,5A to the emitter. Very roughly, efficiency seems at best to be up towards 70%, but generally lower. Problem is, when voltage sags below 3,7V its useless. So if using a battery like the NCR18650B (3400 mah) you will not get full advantage of all the capacity. By looking at tailcap readings, the numbers goes down when battery goes below 4,1A. Basically right away. I never measured amps to the emitter with a lower voltage single li-ion, but I suspect that output goes slightly downwards too (or maybe efficiency goes up). Whatever it does I would either way say its either best suited for 2 li-ions or 4-6 AA batteries.
You can push it beyond 9V, but output goes down a lot. Its quite noticeable when changing the voltage on the power supply from 7,5-15V.

My conclusion: All in all, very flexible simple little driver. Its cheap too. In order to get highest output and probably best efficiency, input voltage in the 4,0-8,4 V is recommended. 4xAA batteries looks to be a very nice combo for it. Its also very suitable for 4-6AA batteries or 2x li-ions.

Thanks for reading

Feel free to come with input on how to interpret the values I have measured.

Question to readers: Does anyone know of a better small 3-18V driver that are better with similar or higher output?

2

Thanks for the review!

3

Thanks. Not sure if many will show interest in the driver, but hopefully someone will find the info useful.
BTW, im pretty sure its this driver. KD sell it for 2.65$

4

Thank you for the time spent on the review! This sort of info is ALWAYS useful. I use a lot of different driver / emitter configurations and its always good to see things like this. Great images as well!!!

Thanks Again. Dan.

5

I use those drivers quite frequently for lots of different projects. That driver works much better with bigger wires so remove the stock small wires and use some 22awg and you will get much better results. They are quite sturdy drivers and when potted with Fujik into a P-60 or any other pill they are great for firearms or high shock usage and also pick up some decent amperage with bigger wires.

Great driver for a great price thanks for the review.

6

Thats good advice. We replace the wires on every driver that we buy. I have yet to see one with anything that is sufficient. I get tired of doing it but it just makes a better light in my opinion. I like the silicone / teflon wire better anyway.

Dan.

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As pictures show… This was done with stock, very thin wires. Ill switch them out with 22 AWG silicone wire… Curious to see the difference.
Should have done that before I did the measurements.

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Looks like a great option for a 2 x 14500 Minimag running an xp-g2. Beatiful macro shot as well! 8)

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Thanks for the review & measurements. I bought two of these for a modding my mower headlights (12v source) but haven't got around to it. At least you confirmed what e1320 told me - 2A @ 12v to an XM-L.

-Garry

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Did some minor changes to OP. Tested with new wires today… Same result.

Thanks, and I agree. … A light similar to the mini mag was the main intent for the driver… But I may find it suitable for another light too… :slight_smile:

?
At 12V I am getting output of 1,27A to an XPG-2 on copper.
With three 14500 below 4 volt (total of 11,34) im getting 0,69A on the tail (in combination with XM-L2 emitter)

11

For your information, The driver IC is YB1682 2A 20V PWM Buck DC/DC Converter.
The data sheet’s link http://www.yobon.com.tw/pdf/YB1682%20Rev.1.0.pdf

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thanks for the review, I have seen that driver and wondered about it.

13

BUMP? I'm specifically interested in the 8.4v to 15v range. I'd like 2A or more output to an XM-L / XM-L2. Oh, and the cheaper the better. Single mode is ok.

-Garry

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So I was testing my work so far on my lawnmower LED headlight project and my testing included this single mode 3-18v KD driver so I thought I'd post my measurements here too.

I used this 3v to 12v power supply rated up to 2A (until I touched the leads together and blew the fuse with no spares on-hand):

I mounted a spare XM-L U2 1B to my heatsink (it was 16mm and my heatsink is tapped for a 20mm star):

EDIT 9/11/2013 - Just realized that I used my meter which is known for being "out of calibration" for the voltage measurements. When I rechecked with my good meter the voltage levels were within .02v of the dial setting. END OF EDIT.

LED lit up just fine from 3v (yes, at 3v on the supply) to 12v. I didn't get an actual voltage measurement of what the power supply puts out at the 3v selection:

Interesting to note is that my power supply voltage only showed 10.46v when set to 12v and driving the LED (it read about 12.1v with no load):

At the 6v setting I read 6.10v load or no load:

Here are my emitter current measurements at each voltage selection:

@3v = 1.39A
@4.5v = 1.39A
@6v = 1.47A
@7.5v = 1.29A
@9v = 1.30A
@12v = 1.36A

After I blew the fuse in my power supply (DOH!), I had to come up with a way to measure from another 12v source:

From the car battery I measured an input current of 0.58A and emitter current of 1.26A. (I don't think there is any voltage sag through the 6ga jumper cables! :) )

I only used my Elenco for voltage measurements. I used my Mastech clone for current measurements along with my custom short 12ga leads.

I guess these measurements are inline with RaceR86's though not as consistent as his.

So this driver doesn't put out the 2A to 3A I was hoping for, which is why I asked for another cheap +/- 8.4v to 15v driver.

-Garry

EDIT - no objects were staged / posed in any of the above photos.

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Great work Garry! Im fairly confidend my PS output was consistent when I used it back then. Although, I relied on the ouput reading which are impossible to adjust 100% precisely. For some reason my power supply does not have that consistent output in the 7,5A range anymore. I really need to put a digital voltmeter on it.

Our numbers were pretty similar, and showed the same tendency. About 1,5A was max emitter current, and generally ouput was 1,3A+.

Yours did work down to 3 volt though, mine did not..

Btw, that R120 resistor might limit current. Like some others have done with similar drivers. A little resistor mod might increase the current to around 2A?

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Do tell more (or link)! I'd love to hear on successfully resistor modding this driver.

EDIT - What about shorting that resistor? What might that do? Risk too much current?

-Garry

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Im not sure anyone have done it on the driver circuit that we got.. Some have done it on this. See this review.

I dont have the driver that I originally tested anymore. But I do have a brand new one in a bag. You see there is R120 where the negative wire connects. I could stack something on top of it if you want me to try it out. ^^

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Sure! (Better you burn up your driver than me burn up mine! :) )

-Garry

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No problem!

Done! ;)

I did not test this driver below 5V, and it was not the same as the one in OP, it was also bought many week later.

At 5V input, i was seeing 1,8A to the emitter. This was higher than the other driver where I was seeing 1,5A. With a bit higher input numbers I saw fairly similar numbers as with the driver tested in OP.

When I set power supply to 7+ish volt. I saw 1,52A to the emitter.

Added R500 on top of the R120 resistor. Same input voltage (7+ ish volt) output was then 1,82A (first 3 seconds was close to 2A). After a few minutes on that setting it was 1,78A. I did not run it for a long period of time, 3-4 minutes. Driver was just sitting in the air with no heatsinking attached to it. And with the efficiency of it, it gets quite warm.

After resistor mod it was 2,13A at 5V input. At 16V, emitter current was down to 1,3A.

In short. R500 on top of R120 increased current with around 0,3A through the range I tested it.

Hope you find the numbers helpful, I can not speak of long term reliability, or how efficiency was affected. I assume its pretty much the same as before. When it comes to long term reliability, this is where you come into the picture! ;) :D

:beer:

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Thanks, that was quick! (I was about to post "Are you done yet?" but you beat me to it! LOL!)

You say it's not the same driver as in the OP, so was it the DX driver you tested? Or was it just a different KD driver? So if I add an R500 (hope I have one) you expect I'll see about 1.66A @ 12v input? You said yours got quite warm. Mine is mounted in a P60 pill which has been filed down flat and screwed & JB welded to the side of the heatsink (with anodizing removed). Do you think it's ok this way? Perhaps I should bench test it awhile and see how it holds up (I do have an extra driver). Also seems I better bench test my other driver and see if the outputs match the first driver (of course I can only measure at 12v - I had to order fuses online as I refused to pay $8 for two fuses locally). .

EDIT - If I am at 1.66A with an R500 added, what would I add (instead of the R500, not on top of the R500) to get to 1.8A or 2.0A?

EDIT #2 - I have these 0.5R from FT, are these the same as R500?

EDIT #3 - Ah, yes. Verified 0.5R is 0.5 ohm (same as R500). Now if I can find them in on my workbench in one of those envelopes!!!

-Garry