Question about TR-J20 modding

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R10500
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Question about TR-J20 modding

Hi, sorry if this is yet another topic on the famous chunky monkey, didn’t want to revive old topics again (some people seem to find it strange).

I’m learning all i need to before i even dare access the driver, but could someone with experience tell me how many amps the driver can manage before it gets too hot for its own good (and my joy)?

Some people have said about rewiring the emitters to 3P4S without mention of changing anything in the driver. Is this driver then a variable output? Is there even such a thing? Because if it is, then my original plan will go ahead as normal, otherwise, i’d probably do something else to stick within the 18V driver output. Which brings me to my next question.

If i were to string 3 6V XHPs in series and drive them at 5A, would i risk burning up anything in the driver? It is 5A through a single channel after all, whereas in stock form it is only getting 1.33A in each of the 2 channels, according to the 3.68A reading at the tailcap.

Also would like to know a ballpark figure for driver efficiency.

Thanks!

R10500
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No one? Surely someone around has had some experience with this flashlight?

KawiBoy1428
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There is a thread some where with different resistor mod’s, I can’t remember what I ended with, but I remember I went a bit too far and poofed the first XML, since it is wired in series, I backed down a bit, replaced the emitter, have a few spare by the way, and it lives today! Still! Thumbs Up

Pretty freaking bright I might add! Steve

Sitting next to the SR95.

KB1428 “Live Life WOT”

texas shooter
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I did the resistor mod. http://budgetlightforum.com/node/32257 LED mod was next and now you can choose between XP-L2 and XM-L2. with both modes should be twice as bright.

R10500
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oh yeah, it’s a real beast, did a ceiling bounce test with the luxmeter and it’s about 30 lux brighter than my TM16GT from 2.5m away. Drawing 3.68A at the tail, not sure how that matches up with everybody else’s. Am considering installing either of those LED’s on DTP’s too, but unless there are better prices out there that i’m not aware of, i could very well be buying a few more flashlights for the price! I just managed to unscrew the retaining ring and got a close look at the resistors. They appear to add up to .2833 ohms with the 2 R620’s and 3R30 resistors, and that implies 2.45A to each LED before inefficiencies. If i added a .47 ohm like someone mentioned, that’d bring it down to .1767 ohms, and if i got it right, each LED will get 3.92A before driver inefficiencies. Time for sinkpads maybe?

@ texas shooter Oh yes, i was just reading your thread, but at my level of experience, i’ve got lots of catching up to do before i can follow suit at all! I should probably start by filing down the spacers.

I probably shouldn’t add the .47 ohm should i? That’d probably destroy the tail switch at those amps?

@KawiBoy damn, those lights! Are those TN42’s in CW and NW i see?

texas shooter
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R10500 wrote:
oh yeah, it’s a real beast, did a ceiling bounce test with the luxmeter and it’s about 30 lux brighter than my TM16GT from 2.5m away. Drawing 3.68A at the tail, not sure how that matches up with everybody else’s. Am considering installing either of those LED’s on DTP’s too, but unless there are better prices out there that i’m not aware of, i could very well be buying a few more flashlights for the price! I just managed to unscrew the retaining ring and got a close look at the resistors. They appear to add up to .2833 ohms with the 2 R620’s and 3R30 resistors, and that implies 2.45A to each LED before inefficiencies. If i added a .47 ohm like someone mentioned, that’d bring it down to .1767 ohms, and if i got it right, each LED will get 3.92A before driver inefficiencies. Time for sinkpads maybe?

@ texas shooter Oh yes, i was just reading your thread, but at my level of experience, i’ve got lots of catching up to do before i can follow suit at all! I should probably start by filing down the spacers.

I probably shouldn’t add the .47 ohm should i? That’d probably destroy the tail switch at those amps?

@KawiBoy damn, those lights! Are those TN42’s in CW and NW i see?

Surprisingly the tail switch never failed or got warm. Trustfire 36650’s had a little less sag. Double check the math, I believe it was around 1 amp per LED when I started unmodified. 3 cells giving 3.68 amps divided by 12 LED’s. By the time you can get 2 amps to each LED, copper pads might start to pay off. Overall it was a fun and easy mod with such a huge area to work with. Overheating was never going to happen. The tube was only big enough to allow for 3×3 16650 cells. Sanyo UR16650ZTA 2500mAh might just make that mod worth while. Generally speaking if I can’t use a hammer, screw driver or blow torch it’s getting a little out of my skill set. Boring out the tube will be a huge task.

R10500
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So it’s actually calculated like so: 3*3.68/12? That explains something fishy i felt about my calculations then! Sure looks a whole lot brighter than the Nitecore’s 3600 lumens at only an amp per LED anyhow.

Boring the tube out is definitely out of the question for me. Am just hoping to use the 26650 Liitokala’s i got but whaddaya know…. flat tops don’t work with it…

By the way, mtnelectronics is probably the best place for sinkpads, LEDs and all that is that right?

texas shooter
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R10500 wrote:
So it’s actually calculated like so: 3*3.68/12? That explains something fishy i felt about my calculations then! Sure looks a whole lot brighter than the Nitecore’s 3600 lumens at only an amp per LED anyhow.

Boring the tube out is definitely out of the question for me. Am just hoping to use the 26650 Liitokala’s i got but whaddaya know…. flat tops don’t work with it…

By the way, mtnelectronics is probably the best place for sinkpads, LEDs and all that is that right?

1 amp per LED is the efficient sweet spot. Yes, Mountain electronics is the best. Illumination supply is also a great store to deal with. Both scary fast on service with great prices.

R10500
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Great, thanks for the advice! Do you think the driver and switch would hold up to 3 6v XHP70’s at 5 amps each by the way? Figured that’d be better than 12 individual XML’s.

texas shooter
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R10500 wrote:
Great, thanks for the advice! Do you think the driver and switch would hold up to 3 6v XHP70’s at 5 amps each by the way? Figured that’d be better than 12 individual XML’s.

No idea and probably no reflector. That’s DALE territory send him an email. He’s modded at least one of them.

18sixfifty
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I’ve modded a few of these. Best results so far was going with a BLF driver, put the emitters on noctigons, de-dome half of them for some extra throw and a more neutral tint. Wire them 3s4p. I also put a side switch in one of them.

I don’t know if that driver would power XHP-70’s but I wouldn’t count on it and I wouldn’t see the advantage in doing so anyway. More floody I guess but you would get a nicer beam pattern with just going 12x XM-L2’s and the heat would be spread out a little better as well that way.

I’m a junky, I mod lights so I can sell lights so I can buy more light to mod so I can sell lights to buy more lights to mod.

R10500
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Was thinking along the lines of aspherics actually, but how to mount them securely inside is another issue.

The largest driver i’m aware of yet is the 46mm SRK driver, not sure if that’s the one you’re referring to?

Unfortunately side switch modding is not possible for me, too much expertise required out of a completely amateur haha. Does the stock driver put out a fixed 18V by the way, or is there a way around that?

I was assuming the complete opposite regards xhp70 vs xml2’s. Aren’t xhp70’s 4 xml’s clustered together? That would mean more luminance in a smaller area than 4 separate xml’s spaced apart, unless there’s something i’ve missed out? And it seems to me that XHP’s need 30W to put out 4022lm compared to XM-L’s which do 1040lm at 10W. Was in favor of XHP because of this greater efficiency.

18sixfifty
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R10500 wrote:
Was thinking along the lines of aspherics actually, but how to mount them securely inside is another issue.

The largest driver i’m aware of yet is the 46mm SRK driver, not sure if that’s the one you’re referring to?

Unfortunately side switch modding is not possible for me, too much expertise required out of a completely amateur haha. Does the stock driver put out a fixed 18V by the way, or is there a way around that?

I was assuming the complete opposite regards xhp70 vs xml2’s. Aren’t xhp70’s 4 xml’s clustered together? That would mean more luminance in a smaller area than 4 separate xml’s spaced apart, unless there’s something i’ve missed out? And it seems to me that XHP’s need 30W to put out 4022lm compared to XM-L’s which do 1040lm at 10W. Was in favor of XHP because of this greater efficiency.

Aspheric lenses would be pretty close to impossible to get to work on a light like this. You would need one for each emitter, they would each have to be perfectly positioned so they all come to the same point. They would not work with XHP’s at all. That would be if you wanted throw. If you wanted flood Aspherics could do that but you would lose a ton of lumens that way.

The size of the driver isn’t what’s important here, other than ease of fitting it in. What you need is a driver that will provide the correct current maxed out. The cheapest way is to mod the existing driver. I don’t know how many amps per emitter that will create, but it’s pretty good from what I remember, not close to max though.

If you want to max out the emitters and give them the most power they can handle then you can use this driver. You take everything off of the driver that comes with the light and use that wiped clean stock driver as a contact board and attach this smaller driver to it.

http://www.mtnelectronics.com/index.php?route=product/product&path=67_11...

This will allow you to get up into the 5amps per emitter range with good batteries. Of course with that much current the emitters must be mounted onto noctigons or sinkpads or they will die a very quick death, not even seconds, more like a fast flash of light and gone.

XHP’s are four XM-L2’s but three of them in this light would be all flood. Why? Because although they are bunched together they still have the exact same surface area as four XM-L2’s and you would only have three small reflectors. If you put an XHP-70 behind a small reflector you have four times the surface area, none of which is even perfectly centered. (throw is calculated by surface intensity of the emitter by diameter of the reflector). Maximum throw is created by using the smallest emitter with the largest reflector. An XPH-70 is a large surface area and when you put it behind a small reflector it’s very floody with a large center hot spot.

Keep this in mind when using FET (direct drive) drivers. Each XM-L2 or XP-G2(3) or XP-L2 can handle all the current from 1 battery without frying, so long as it’s on a noctigon or sinkpad. So if you have three batteries in series (like on this light) then you can drive Three of any of these emitters in series and they can take it. Not Two, that would kill them and not Four it wouldn’t be very bright. (three batteries in series drives 3 emitters in series to their max (2 drives 2 and 4 drives 4, etc) So you have to match the number of emitters in series to the number of batteries in series. How do you get 12 emitters to work with three batteries? That’s were Parallel comes in. You do Four sets of Three emitters in Series. (3s4p) This essentially means that you are still driving each emitter with a single battery. That FET driver I posted is “direct drive” with low resistance. This means that it’s throwing pretty much all the power that the battery has at the emitter. Using this driver you are able to come close to maxing out each emitter. It’s a little bit short of max, but only because it’s next to impossible to use heavy enough wire to make that happen. So you end up using wires that are not as thick as you could and the thinner wires create some resistance of their own.

Now do you want to really go this far with this light? That’s up to you. It’s not exactly a “beginner” mod and it’s not cheap, you can be almost guaranteed that it will take more than a few tries and lots of troubleshooting to get it right. but it’s far from impossible and would be a heck of learning experience.

If you decide to go this route let me know and I’d be glad to talk you through it. Feel free to PM me anytime with questions.

I’m a junky, I mod lights so I can sell lights so I can buy more light to mod so I can sell lights to buy more lights to mod.

The_Driver
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Can anybody tell me the diameter and thickness of the glass lens in this light?

R10500
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yeah, throw is the way i’m going, the awkward tri-beam at short ranges notwithstanding. I know the 70 isn’t the best platform to get throw out of at all, but at 4000+ lumens and with an aspheric focused to infinity, i don’t know, maybe that’ll do something? Would this make the case for XHP70’s any stronger?

Let me get this straight, because i’m not sure that i understand how it works. Using 2 batteries would fry only the 1st emitter in the string because more amps would be drawn out of the batteries to equate to the V=IR equation, and when using 4, fewer amps are drawn out? Also, do tailcap readings only reflect the amps drawn out of the battery the negative lead from the multimeter is contacting?

I remember reading a post about using the stock driver as a contact board( was it yours?), but don’t know how that’s done. Is it connecting both drivers by means of soldering wires to them?

Thanks, i greatly appreciate that, it’d be very helpful, but i wouldn’t try until i master the basics of electrical theory, which i completely lack now! (Got some R470’s on the way by the way)

R10500
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I remember seeing a post on the thickness and width of the lens, but i can’t seem to find it at the moment. i’ll get mine out and measure it in a moment.

R10500
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Diameter is 84mm and thickness is 2.75mm. Not AR-coated. Wish i knew where to get one on the cheap

18sixfifty
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R10500 wrote:
yeah, throw is the way i’m going, the awkward tri-beam at short ranges notwithstanding. I know the 70 isn’t the best platform to get throw out of at all, but at 4000+ lumens and with an aspheric focused to infinity, i don’t know, maybe that’ll do something? Would this make the case for XHP70’s any stronger?

Let me get this straight, because i’m not sure that i understand how it works. Using 2 batteries would fry only the 1st emitter in the string because more amps would be drawn out of the batteries to equate to the V=IR equation, and when using 4, fewer amps are drawn out? Also, do tailcap readings only reflect the amps drawn out of the battery the negative lead from the multimeter is contacting?

I remember reading a post about using the stock driver as a contact board( was it yours?), but don’t know how that’s done. Is it connecting both drivers by means of soldering wires to them?

Thanks, i greatly appreciate that, it’d be very helpful, but i wouldn’t try until i master the basics of electrical theory, which i completely lack now! (Got some R470’s on the way by the way)

You would have more than an awkward tri-beam. You would have three sets of four beams. The XHP-70 looks like it’s a single emitter but because it’s actually 4 XM-L2’s jammed together they are still separated by enough space that under an aspheric they will come out as four beams that never do intersect. So even if you could get the three emitters to intersect perfectly you would still have four beams. I imagine they would get pretty close eventually IF you could somehow manage to line them all up perfectly but it still wouldn’t be the most throw from the light because the XM-L2 is not the best throwing emitter under even the best conditions. I have built one multi-aspheric light and that was with 4xXP-G2’s, which throw further than XM-L2’s and it was still a waste of time because the lenses needed to be relatively small. Theoretically if you wanted to turn this light into an aspheric thrower your best bet would be to use a single de-domed XP-G2 S4, right smack in the middle and one huge aspheric lens. When you are going for max throw it’s the same with reflectors or lenses, the bigger the better and multiple small ones don’t cut it.

I’m not saying it would be a complete waste of time, it would make for a neat light but it would be an unbelievable amount of work creating the housings to get those three beams focuses and it would still not get you the most throw or a very nice looking beam.

On the batteries frying the emitters. If you put Two batteries and wire them to Two emitters in Series you are fine. Wire them to Two emitters parallel and it will fry both of them. I suspect that if you were to somehow manage to wire 12emitters all parallel to two batteries it might not fry them if you got the wires exactly perfect so that none of them got any more power than the others. This could create enough battery sag to save the emitters, but I wouldn’t count on being able to get the wires perfect and once one emitter fried the next would go and the next and the next.

And yes when you take a tail-cap reading you are only reading the draw from that end. A more accurate way is to read the current at each emitter. I am no expert on this part at all. Although I have built hundreds of lights I haven’t taken a current reading in years and I don’t think I ever did one correctly anyway. I know roughly what you get from each configuration and try not to post too much on exact amp draws or even exact lumens or KCD. I’ll do so in a general way but I stay away from making too specific of a claim. I give ballpark figures and that’s about it. People have been trying for years to come up with a perfect measurement system for these things and I leave that to others.

Yes, using the driver as a contact board means running wires from your old board to your new one and then on to the emitters. After you take all the stuff off the old board you use your DMM to isolate a positive and negative and solder the wires there.

I’m not even close to an electronics expert, others here are way past me on that part. However, even though I’m no expert on the electronics part, I’ve become fairly expert on the actually building of lights and even building and modding drivers. I guess what I’m saying is that you don’t need to know every detail of how the electronics works to build a great light. For some people here the electronics is the most fun, for others it’s the software design. For me it’s just the actual construction of the lights and seeing the final product.

Modding the existing driver is great way to start and good luck.

I’m a junky, I mod lights so I can sell lights so I can buy more light to mod so I can sell lights to buy more lights to mod.

R10500
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Oh yeah, that’d be painfully strange( strangely i’d had such a dream once about this), but i’d really been planning on a dual aspheric, a pre-collimator positioned just far enough to get all the light onto the main lens, which will be a 100mm FT lens, which is focused to infinity. That’d make it 3 circular beams. Unless i get the new XHP70.2’s?

I would go down the XPG way, but what i understand is that it’d be not particularly bright and have a very tiny spot, and at the distance it will throw to, one would need visual aids to see where it hits. My rationale behond XHP70’s (and the dual aspheric hence) is partly due to their massive output, so even though due to their large area they wouldn’t ever throw as far as an XPG, they’d still go quite a distance and light up a broad area, but could illuminate a varied area size by adjusting the main lens. If this idea i have in mind can achieve the sort of results i’m anticipating that’d be awesome.

Knowing how aluminum is a poorer conductor of heat but better at dissipating heat than copper, would it be necessary to maintain a minimal distance between the sinkpads, if i stick with XHP70’s? And are the Arctic Alumina grease and paste the best to secure the sinkpads to the heatsink shelf?

So it is because of the voltage drop across each LED in series as opposed to the full voltage from the batteries across each LED in parallel that makes the difference, is that correct?

By getting the wires perfect, do you mean using the correct gage and length?

Lastly, how do i use the DMM to isolate a positive and negative? Aren’t the + and -ve poles on the drivers marked already?

I’m not so sure i’d want to go as far as being an electronics expert myself, but i’d be more than content to reach your level of expertise. Inspired!

18sixfifty
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R10500 wrote:
Oh yeah, that’d be painfully strange( strangely i’d had such a dream once about this), but i’d really been planning on a dual aspheric, a pre-collimator positioned just far enough to get all the light onto the main lens, which will be a 100mm FT lens, which is focused to infinity. That’d make it 3 circular beams. Unless i get the new XHP70.2’s?

I would go down the XPG way, but what i understand is that it’d be not particularly bright and have a very tiny spot, and at the distance it will throw to, one would need visual aids to see where it hits. My rationale behond XHP70’s (and the dual aspheric hence) is partly due to their massive output, so even though due to their large area they wouldn’t ever throw as far as an XPG, they’d still go quite a distance and light up a broad area, but could illuminate a varied area size by adjusting the main lens. If this idea i have in mind can achieve the sort of results i’m anticipating that’d be awesome.

Knowing how aluminum is a poorer conductor of heat but better at dissipating heat than copper, would it be necessary to maintain a minimal distance between the sinkpads, if i stick with XHP70’s? And are the Arctic Alumina grease and paste the best to secure the sinkpads to the heatsink shelf?

So it is because of the voltage drop across each LED in series as opposed to the full voltage from the batteries across each LED in parallel that makes the difference, is that correct?

By getting the wires perfect, do you mean using the correct gage and length?

Lastly, how do i use the DMM to isolate a positive and negative? Aren’t the + and -ve poles on the drivers marked already?

I’m not so sure i’d want to go as far as being an electronics expert myself, but i’d be more than content to reach your level of expertise. Inspired!

Always use the thinnest possible layer of thermal paste/grease, even the very best is not great at conducting heat. What it’s best at doing is removing air pockets. Those tiny air pockets are insulators and the point of putting down paste/grease is to get rid of that air. People debate endlessly on what is “best”, but arctic silver is very good. There are products that are “better” but it’s debatable if it’s worth spending any extra money on getting the very best. I use Wakefield Deltabond 153 but it’s $40 and probably not any significant amount better than Arctic silver. More important is making sure you use a very thin layer and that you have mated the two surfaces in a way that doesn’t allow any large gaps at all. If the area you are mounting the emitter to is rough it’s important to sand it down as smooth as possible. I use various grades of sandpaper until it’s basically polished. You want as much metal to metal contact as possible between the bottom of the sinkpad/noctigon and the heatsink. If both were absolutely perfect you wouldn’t need thermal paste at all, you could hold them in place with screws.

When you put the emitters in series it takes twice the current to get the same amount of amps to two emitters. When you put the emitters parallel you get roughly the same amps to the emitter no matter how many emitters you wire that way. I say roughly because it’s a bigger drain on the battery if you have a bunch of them wired in parallel, but usually not enough to consider wiring them safely hoping on thermal sag to save them. How should I put this? Hmm. OK, Wiring them in parallel is the same as if you were to run a separate set of wires to each emitter, think of it that way, because it’s essentially the same thing. It would take a lot of emitters wired that way to drop the amps quick enough to save them from burning out. It’s not really worth trying to do it and trust me, I’ve tried it and lost emitters a bunch of times. I’ve also tried running thinner wires hoping the loss of current to the resistance from the small wires would stop them from frying. All I did with that one was to cook my wires. So it’s best just to remember that each emitter can handle a full load from one battery. In the case of XHP’s and MT-G2’s it’s TWO batteries though, because they are 6 volt emitters. It’s just with XPG’s XML’s and XPL’s that it’s a one to one ratio. It’s convenient that it works out this way though. It makes it much easier to figure out the correct way to wire them.

It makes it more difficult when it comes to wiring XHP’s with a FET driver though. For instance your light won’t work right in the 3xbattery mode using XHP’s and a DD FET. Three batteries run into a single XHP or a group of XHP’s parallel is too much and will kill them. So if you do go with XHP’s you have to hope that modding that driver will actually work with XHP’s and I wouldn’t count on it. The difference is that the XHP’s are 6volts and I don’t know how that driver will react. From my experience using a wide range of stock drivers to attempt to build 3xMT-G2 lights I wouldn’t hold out much hope. I think ComfyChair might be the only guy I know who managed to get a Stock driver to work for any length of time with 3xMT-G2 (also a 6volt emitter). I tried at least a dozen different drivers and they all died after a short while. It wasn’t until we started building these FET DD drivers that people started having any real luck building triples with these 6volt emitters. I know a bunch of guys who tried it who failed.

I built a Triple XHP70 diving light the other night and used the FET driver but that was because the diving light uses 2×26650 and I could run all three emitters parallel. If it was a three battery light it would not have worked and I don’t know of any stock driver that will reliably drive 3xXHP70 although there must be because they sell a few triple XHP70 lights. I haven’t had a chance to tear one apart yet and see what they did. For all I know they might just be using a FET driver too.

I’m a junky, I mod lights so I can sell lights so I can buy more light to mod so I can sell lights to buy more lights to mod.