Thrunite TC20 - XHP70 - 3800lm

The problem is that for most people only lumens are important. Manufacturers wanting to “meet the requirements” of these customers, install P2 diodes because they are the most efficient. Of course, the color suffers. There are XHP70.2 diodes which have 5000K and CRI 80 and 90. They are N2, M4 and M2 models, but for comparison their performance:
P2 CRI70 1830 lm for 85 degrees
N2 CRI80 1590 lm for 85 degrees
M4 CRI90 1480 lm for 85 degrees
M2 CRI90 1380 lm for 85 degrees

Knowing me, as soon as I get N2 I will make a change :slight_smile:

I look for M4, but hardly available to buy.
Mike

Link M4

Link N2

Only probably not available from stock. In addition, I see 12V and in TC20 is from what I know 6V

That’s why I wrote “hardly available to buy” :slight_smile:

I have a problem with turbo. All cleaned, it drops from circa 8A to 6A in 1 sec.
Any clues?
Mike

12V is merely a matter of which board it’s on and how that board is set up. The XHP-70.2 can be set up to run in 6V or 12V, it’s the same emitter either way.

The chaufer in the study. :wink:

Oh, sorry, what multimeter or clamp meter are you using to get that 8A reading? If a clamp meter, what gauge wire for your loop? What cell, and is it fully charged to 4.20V?

Great news, I will be hunting for a super hyper pure white LED :slight_smile:

I like the Noctigon or MaxToch 6V MCPCB’s for their heavier trace in the 6V configuration. Since we like powering these emitters up, a heavier trace to carry that current just makes sense… SinkPAD also has a nice 6V version of the XHP-70/70.2 MCPCB. You should even be able to get similar directly from Simon at his Convoy store on Ali Express. :wink:

Cell fresh from charger. I use DMM with thick cables I used to measure different 8A+ lights. Only this TC20 show me this amperage drop.
Other cell is on slow boat from China, maybe I will try with 18650 30Q cell I have.
Mike

Mike, I have yet to see a DMM that will accurately measure amperage over a few amps. The UNI-T clamp meters that were in a group buy a while back are good meters and the idea back then was to have as many of us on the same page as possible so current readings would be more standard across the board. I can’t say it’s a fault of your DMM that current drops as you’re describing but at the same time I don’t think I’d trust the reading from the DMM, even a Fluke can’t accurately measure with the stock leads and even if you use heavier gauge leads the sheer length of most attributes to incorrect numbers.

If the long heavy leads are adding to the resistance through the cell then the cell will drop voltage faster than it would tend to in the light, I’ve found even a 6” 12ga lead as a loop in use with a clamp meter causes a drop in lumens on the light box, so every little thing comes into play on these.

Keep in mind that on any cell the driver is boosting the available voltage to the emitter’s requirements, pulling 40-50% more from the cell than goes to the emitter. So a 10A pull to provide 5A to the emitter will definitely put a hit on a smaller cell, any cell for that matter.

I’d like to stress that all lumens readings and all current readings, ALL of them… mine, robo’s, lexel’s, all of them, are the numbers we got at the time from the specific cell to the specific emitter through the specific driver on a specific day. It will change almost every time you take the readings as the cell loses life capacity, as the emitter deteriorates in it’s own life cycle, as heat robs efficiency and so on and so on.

If we got 100 members to order 100 consecutively made clamp meters and 100 consecutively made cells and 100 consecutive made lights and we all also ordered 100 consecutive made chargers… we’d have readings that varied a surprising amount when we tried to compare. Natural variance. It’s unavoidable.

So when we see numbers posted it’s not hard and fast concrete evidence of exactly what you should expect from yours, it’s an estimation of what to look for. Slight variance is expected, large variance can be an indicator there is a problem that needs to be rectified. Sometimes even large variance cannot easily be overcome. It’s the nature of the beast…

Dale, I measure mine triple nichia S2+ and shows 9A on the same DMM, no drop. TC20 drops after 1s after switching turbo on.
I can see and measure light intensity drop with or without DMM involved.
The question is: is it a torch or battery related?
Mike

That sounds like what mine was doing after I cleaned the light contacts and cell ends the first time.

Go back and reclean the cell ends really good and also any points of contact such as the tube ends , brass ring inside the head , threads , springs , and rub the mess out of them. I was surprised to find what the second really good cleaning did on my light.

I can almost guarantee that a clamp meter would show significantly higher current readings than your DMM. Seen it hundreds of times. I soldered 12ga leads into the V sockets of my DMM to make it impossible to use my DMM for current. lol I have 2 clamp meters now, they are both usually virtually spot on with each other on current readings.

Try like robo says and double check your cell contacts, you’ll probably find gains by doing so.

Dale, I measure light drop (I see it also) on turbo without any DMM connected.
Just tested with 30Q cell, drops too, so cell excluded.
It is not go from turbo to lower mode, just dims.
Mike

I bought two LEDs from Simon and I was satisfied so I can buy something from him again.

Mike, maybe you should talk to Thrunite about it and see if they will replace it. Sounds squirrelly to me…

Well, I could not stand it :), but too much of this bile.
I decided to check what the scalping of the diode is giving.
The plate is thick 2mm, copper and really solid. Diode like a diode. The paste is not evenly applied, and the centering diode is probably cut by the child.

First, I cleaned the edges and lightly cut them. Of course, it did not give anything, as the crown was yellow, it still is. The next step is total scalping. Effect? Hmmm suck. So it flew the color temperature from 4959K to 4154K.

Of course, the crown is still yellow, generally everything is yellow now. Concentration increased as one could expect, but not terribly. I do not like the end result so I ordered a new diode from Fasttech N4-3A and we’ll see what it will be like. This is my favorite shade, 3A, but what about the crown? We will find out about it in a month :). I was looking for the LED CRI90 or M4 or M2, but nobody has it (5000K).

The 70.2 is a flip-chip technology emitter, meaning the connections are on the bottom of the chip, no bond wires. As such you can clear more of that phosphor away, right up to the edge of the die itself, and this clears up a lot of the yellow aura. Also helps to tighten the hot spot.

I bought a scalpel and a lot of blades for it, have found that if I hone and polish the scalpel blade and use a bit of silicone grease on it the resulting slice across the die face to remove the dome is nice and smooth…. it takes a single stroke slice action, not a push but a slice across in a continuous motion, this nets the smoothest cut for me and the result is a nicer beam profile. YMMV