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

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

-Garry

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:

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

Same SKU from KD, just not the same sample as in OP. Do not ask me why I saw slightly higher output.

Yeah, the resistor you linked to from FT was the same as I used.

Not sure if I followed you in edit 1. But you want to see 1,8A+ and you only want to use one resistor.

If you have something in the R330 - R430 range you might want to try one of those. If not, R500 will give you a little increase. I don't know your input current though. As said, R500 gave me roughly 0,3A increase from what I started with..

What I meant was, if I am getting 1.36A emitter current at 12v now with no add'l resistors, what would I add on top of the R120 to get to 1.8A or even 2.0A?

I have 0.5R, 0.22R, & 0.12R as far as low value resistors go. What would adding a 0.22R instead of the 0.5R do?

-Garry

I would just put on the 0.22R and see where that takes you. Just make sure you see the emitter amps when you turn on the driver. Some drivers work in mysterious ways, so just be ready to turn it off in case you get very high current for some strange reason. Always test on a emitter that you do don't care about. Again, in case the driver work in mysterious ways.. :p

Id guess you need around that 0.22R in order to get where you want to go. I have not done the math though. Give it a shot..

Oh, dont blame me if something goes bad.. 0:)

Ohm’s law in different forms can help you here.

  1. E = I x R
  2. R = E / I
  3. I = E / R

1. SenseVoltage = StockCurrent x StockResistance *(from unmodifed driver)
2. TotalResistanceNeeded = SenseVoltage / DesiredCurrent *(Desired modification)

To calculate the total resistance of multiple same value resistors just divide one resistor value by the number of resistors used.
Example: .5R + .5R + .5R + .5R = .5 / 4 = .125

To calculate the total resistance of multiple different value resistors:
TotalResistance = 1 / ((1 / RValue1) + (1 / RValue2) + …)
Example: .2 R + .5 R = 1 / (1 / .2) + (1 / .5) = 1 / (5 + 2) = .14

I find this easiest to do by setting it up in a spreadsheet and then just plugging in the values I know.

Edit: This is the theory, and assumes that the other components of the driver can handle in the increase current. I have found it to be a pretty good predictor in the few drivers I’ve modified. Your driver may react differently. :slight_smile:

Exactly the response I expected! :slight_smile: . I’ll post back my reading if/when I get to it.

-Garry

Ugh! Last time I listen to you! Installed resistor (its smaller than the R120 original). Tested with a single Li-ion @ 4.14v gave 1.68A. Connected to car battery and within a second "POOF"! Dead! Driver outputs test showing a short (0.2 ohms) and the LED won't light direct drive from an 18650. Ugh!

Think I'll leave the remaining two drivers alone.

-Garry

Be ye warned what happens when mere mortals tamper with powers beyond their ken.

I really didn't expect this to happen. Does it make sense? Or do you think I might have done something else like overheat the new resistor when I soldered it on? Since the new resistor was smaller than the original, I had to "drag" solder across the top of the bottom resistor to connect to the new one. Here is a pic but I don't know that you can tell much (pic prior to burning up the driver), best I could get with my phone:

The black lead is coming right over top of the sense resistor I added. You can see my solder blob to the right side of that resistor where I "drug" the solder over top of the bottom resistor.

-Garry

Garry, you did not listen to me. I said specifically, do not blame me. :p

As for what happened? Too much power for something probably happened. Shit happens when limits get pushed too far.

This is a new close up of my driver with the resistor. (looks the same as the on pictures in OP)

If you are going to buy a new one, you might consider to try this. 1,8$ if you find a 10% coupon.

Btw, is there a reason why you can not use this?

The first link - that's what I bought originally and am using now. The second link - I forgot about that driver. Biggest issue I see is that I need a "pill" of some sort to mount the driver in. I would also really like to get rid of the next mode memory.

-Garry

Ah, FastTech does have a "driver pillar" which takes a 22mm driver and should have about 15mm depth. $3.96 each though, so this & 2 new drivers raise the price of my build. I won't pursue this until someone can remove that next-mode memory on that driver though!

-Garry

When I get home from work I’ll check one that I have. I added a resistor to see if it helped at lov voltages (it doesn’t).

I have 2.15 amps on mine iirc.

Interesting Garry. As far as I saw while looking quickly over it, there was no solution to the next mode memory, only a way to make it into a one mode. I would like to have the modes on mine.

I actually saw 2.15. But i noted 2,13 (as mentioned earlier). But that was after the R500 was added, and at around 5V input.

You are talking about emitter current right? I remember a few who mentioned theirs were 2A in some threads, but the ones I and Garry got were 1,5A max, and generally lower.

And remember, after resistor mod mine was apparently ok at low voltage (single li-ion). It wasn't until I went for 12v+ that I blew it up. But RaceR86, you did test up to 16v with the R500 added, right? And yours didn't blow, although we don't know how long it would last that way.

-Garry

Yes, 16v input with R500 added. (only 1,3A to the emitter though) I never ran it for long though.

5V was slightly above 2,1A.

I had 7V input when I tested it for several minutes. (About 1,8A to the emitter)

I'm thinking I'll just go ahead with these drivers stock in my current build and if I feel I'm not getting enough output I'll consider upgrading to that driver from LightsCastle (perhaps converted to single mode) with new pills; might be next year though.

-Garry

Update on my voltage readings in post#13: I used my meter which has been found to be out of calibration by mistake (I forgot). It appears to read approximately 0.10v too high. I really need to either get rid of the meter, figure out how to calibrate it, or at least put a label on it to remind me.

-Garry