Supbeam K50 V2 Mod Thread

Ok - I decided to stay up & have a few :beer: ’s , & discharged some of my Samsung ICR18650-28A’s down to 3.30 - 3.34v.

Tested in the K50 for a little over 2 mins on high.

Externally, no noticeable difference in heat.

Took the carrier out, & noted that the end was slightly warm. Not hot. But warmer than the rest of the carrier.

I had to put it up to my cheek to get a better idea of the temp difference, as my fingers are pretty heat-tolerant due to my work.

The battery indicator light was flashing red when I started the test, & I noticed that it had gone out completely when I switched it off.

Thanks FmC. That is nice to know. Cheers mate!

My full update below:


Ive had no issues with the driver. With my resistor mod, input amps is 2,7A @ 12V and 2,9A @11V (11v divided on 4 cells means 2,75v on on load) when tested with a powersupply (should roughly give efficiency around 80% or a bit lower). I did not think up towards 3A should be an issue for the springs in the carrier.. Yet, when I did some startups with some unprotected NCR18650PF cells at around 3,3V there were some issues. It started with full output, but very quickly showed some strange behavior with the output. I took out the carrier and the bottom of it was burning hot.

Springs had "sagged" a bit. Typical issue if they are seeing too many amps.

I replaced the springs and added some 22awg wire too them. Tested again. Battery carrier got really hot in a short time.

Top of the carrier is easy to disassemble. Nothing to see there. The bottom end is not supposed to be opened. I used a hot air gun on the stuff that was inside the screws in order to screw them out. Here is the battery carrier bottom side.

Notice component at the far right. Not sure about the component at the far left.

Here is a picture of the electronics in the tail:

Not sure what do do know. Sup/Acebeam can sell me a new carrier. Price is not bad considering all the components on it. (20$ + a little bit in shipping)

Im considering to just get a new carrier instead of trying to replace parts in mine that may be broken or damaged. And then just mod the driver back to stock....

My light works nicely otherwise. Ive been using it outdoors a bit the last two nights. Taking it for a walk and comparing with other lights. But im not a fan of a light that seems to have issues with low voltage cells. Im not a fan of using the built in charging system when Ive got some components that look like they do.

I wonder if the electronics in the battery carrier is not up for the task of increased amps when cells get low, which naturally increases amps more in a regulated light like this.

Electronics gurus, feel free to share some insight and knowledge.

Wow, that a lot of crap in there for a feature I'll never use (in-light charging).

Wow, lots of stuff in there. Seems like we are going to need a OSH Park DIY alternative carrier for this light. Wonder why they didn't go 2P2S on this light. Would have simplified the design a good bit.

Wires on the tail PCB go to the charging port, right? What do the wires on the carrier PCB go to?

Yupp. Wires on the tail go to the charging port.

On the carrier:

Center contact path is seen in the picture.

Red wire on the carrier goes to the middle contact path.

White wire goes to the contact path closest to the edge.

OK, so I will pose the question and see what all you gurus maniacs out there can do.

Can the stock driver be modified to handle the voltage for an MT-G2? I figure the MCU/controller might have to be "protected" by some type of bleed like a zener, but.... Is this a FET based driver? If so, can the circuit be manipulated to use 7135 chips for regulation and get rid of the fet?

In other words, I want an MT-G2 at 9 amps, (never gonna get 9, but...) and do it with regulation instead of DD on high. AND I want to continue to use the normal magnetic ring for modes, so that whole part of the driver has to remain the same.

Anyone???

Everyone???

I don't have a light yet, don't know where it is, but it should come if they didn't stop the shipment, LOL.

maybe 6x18350 S/P for the batteries - Better back off to about 5 amps then. EDIT: Sorry, thought it was 3 cells, not 4. Series? What is all that crap in the carrier? Just for recharging?

Stock carrier is 4S, or 16.8-12v. Driver is a buck driver, but if other reports are correct some component on the board (the buck controller) has an output voltage limit, and cannot adjust voltage up high enough to run a MTG2. It would take an extraordinary amount of luck to find a pin-compatible controller, like something in the same series from the same manufacturer, that had a higher output voltage limit. Otherwise, I don't know of any way to keep the magnetic control part.

We can compare and contrast the parts of the TN31 vs. TN30 to figure out which component is causing the voltage limit.

Do you know which PIC is used on those other models? I don't see anything on either side that could be a buck controller, nothing other than the PIC with more than 5 pins.

edit: For people who understand whatever language this is written in: http://ww1.microchip.com/downloads/en/DeviceDoc/41288F.pdf

Sorry didn’t know it was a 4 cell carrier. Series, didn’t know that either, didn’t look either. OK, so I will trash the stock driver, magnetic ring and carrier. It will be an MT-G2 light when I get done, one way or the other, (or it will be a heap), with no recharging in the light and a momentary switch I guess, with the tail switch being a cut off… Maybe

Are you sure OL, that sounds like a whole waste?

I think those parts made that light so expensive and unique.

Why not get a K40M, which was made for the MT-G2... I know it has a smaller head, but gosh, taking all that stuff out seems to be a waste.. or at least people would be able to get some original parts, when their mod goes wrong.

Or see if there's a way to get a K40M driver. Since the K40 & K50 (and whatever other lights) use the same basic driver PCB, the M driver should fit the non-M lights too.

work this k 50 not with 8x CR123A ? with one mt-g2? = 6V for old-lumens ?

The driver already has a 16.8 volt input, it's the output side that isn't capable of putting out the voltage needed to run the MTG2. More input voltage isn't going to change that.

Seems a shame to do that to a light like this, but of course it’s yours and you can do what you wish.

I just put an MT-G2 in a Courui that has 3 bays in parallel. I used 6 18350’s and it ran over 14A from the BLF17DD Z piggybacked on top of the original driver….stripped to be only a contact board. I had to tone the UI down to 197 from 255 to get 6.23A for 3030 lumens OTF, 4481 lumens was just too much for this light.

So I would think you can achieve the 9A you’re looking for, all in how you go about it I guess.

It occurred to me that RaceR86's cell carrier problem sounds like it's most likely a manufacturing defect. Wouldn't at least one of those Vinh modded lights exhibited this behavior by now? I guess it's possible all the recipients only use topped off cells or shelf queen the lights, but it seems unlikely.

Considering that FmC`s carrier showed a sign of becoming hot. Could also mean that increasing the amps from a mod leads to the issue I was seeing.

Doing a runtime test may not be enough to "trigger the issue" due to stepdown.

I checked with one owner who bought two K50vn today. No signs that the battery carrier was opened up and modified. Sealed just like stock. He had not run the batteries low. I know at least one guy have that ran his light low. But how many have started the light on high with low voltage cells?

I would assume the driver mod would not damage the carrier due to all the K50vn out there. But that assumption did not work for me. Most of them are probably living a quite peaceful life being babied. When that is said, I cant say for sure that any components in my carrier are broken. But one of those components sure did not look well. And the heat has got to come from some place.... Cant be healthy for a battery carrier to become that hot..

Hopefully there are some US based owners of K50vn that can do some proper independent testing.. J)

(And hopefully they have some sort of warranty)

I didn't get a chance to charge up or find 4 matched low voltage cells to check. I will try tomorrow.

It looks like the carrier is only supposed to go in one way. It appears that the thicker side would go towards the tail as the tail has 3 contact surfaces and the thicker side of the cell holder does too. It sure would be easy to accidentally put this carrier in backwards. Not sure what that would do, but be careful folks. Hopefully, they designed the light so that such an incident will cause no damage.

I think this driver can mod to use third party driver too such as NANJG with magnetic ring still functioning

I found two control pins. one goes to Buck FET controller and other to tiny FET that connected with sense resistors and LED -V

Can someone help me to find purpose of these two pins if I tell the test method ? because I don’t have a K50

I suspect second FET is used to Dimming. If its true, dimming modes should off once that FET bypassed.