Q8 modding

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Lexel
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Agro wrote:
Dedomed XHP50.2 should have similar cd/lm to XP-L HD with more than double output, right?

depends on the batteries

but yes the Q8 draws about 5A per emitter
the 50.2 may draw 8-10A per emitter

I made a Q8 2S driver board

Mike C
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For 2S lights the A705NGT might be of interest. They are basically 7135s that are rated for 12V. I’ve just built a 6V MT-G2 headlamp based on them so I’ll be giving them a go.

For the Q8 I have a 4S design on the way for XHP35 HI with ATtiny1634 MCU and CAT4101 regulators (controlled by digipots). The CAT4101 may well be a bad choice at a high price tag, but they are easy to use for an electronics noob like me.

Lexel
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http://www.ebay.com/itm/10PCS-A705NGT-330-Encapsulation-SOT-89-/132216716613#shpCntId

too bad they dont ship to Germany

Mike C
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Lexel wrote:
http://www.ebay.com/itm/10PCS-A705NGT-330-Encapsulation-SOT-89-/132216716613#shpCntId

too bad they dont ship to Germany


They don’t? Where does it say that? That’s where I got mine. Would be odd that they send to Sweden but not Germany.
kiriba-ru
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Excludes: China, Austria, Germany, Switzerland

Schoki
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Someone else already developing a buck driver for the Q8?

The Miller
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Oh wauw it looks very promising all these driver plans Smile

Schoki
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Well, I got one design, but I found a different buck controller (that should be better than my first one) yesterday. I probably make a second board with the new IC.

Texas_Ace
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Schoki wrote:
Well, I got one design, but I found a different buck controller (that should be better than my first one) yesterday. I probably make a second board with the new IC.

Which IC was that?

The Texas Buck should work as a base for a Q8 buck driver, although it would not put out as much total power as the Q8 does now. Although I think we have found some better PFET’s to use compared to the one in the design.

The only practical way to make a buck driver work in the Q8 is to rewire the cells to be in 4S. There is simply not enough voltage overhead and you need too much current to make a 1S buck drive practical.

Schoki
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I used the ISL8117 in a 4S configuration and it should be able to output 20A.
Edit: But with that controller you need an inductor with 10uH (limiting the current capability), but now I found a controller that needs 4.7uH (with the same frequency and more efficiency, and the frequency is pretty low for less switching losses).

Texas_Ace
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Hmm, a quick glance at the ISL8117 looks really interesting. I really like what I saw, that indeed would seem to make a good IC for the Q8, it is even small enough that it could fit on some smaller drivers.

Whats the new IC you found?

I am actually working on another project where we are trying to drive 15A+ on a buck so a new option would be nice.

Schoki
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The other one I found is an LM5145/LM25145. They both are nearly the same controller, the LM5145 has a higher maximum input voltage: 75V compared to 42V at the LM25145. Everything else is the same.

Mike C
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kiriba-ru wrote:
Excludes: China, Austria, Germany, Switzerland

I stand corrected, I found it now… Pretty odd, shouldn’t matter what EU country they send to.

Well, I’ve been using them in one of my headlamp projects and they work alright, but the ones I have don’t draw 330mA, the consistently draw 250mA. I had to check if I got the wrong ones, but they are marked as 330mA versions. Other than that they same to be very reliable. I’ll be trying to get the 350mA versions next time.

Schoki
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Texas_Ace wrote:
I am actually working on another project where we are trying to drive 15A+ on a buck so a new option would be nice.

And what IC did you choose for your project, and who is working on it with you?
The Miller
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Mike C wrote:
kiriba-ru wrote:
Excludes: China, Austria, Germany, Switzerland

I stand corrected, I found it now… Pretty odd, shouldn’t matter what EU country they send to.

Well, I’ve been using them in one of my headlamp projects and they work alright, but the ones I have don’t draw 330mA, the consistently draw 250mA. I had to check if I got the wrong ones, but they are marked as 330mA versions. Other than that they same to be very reliable. I’ll be trying to get the 350mA versions next time.


So if I understand correctly one could make a driver working on 6V input and with the number of these chips control the output?
Like a 8*7135 for XPLhi, we could make a n*chip for XHP70.2?
Mike C
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The Miller wrote:
So if I understand correctly one could make a driver working on 6V input and with the number of these chips control the output?
Like a 8*7135 for XPLhi, we could make a n*chip for XHP70.2?

I’ve used them for a 2S driver for the 6V MT-G2 here: http://budgetlightforum.com/node/55890
They are basically 7135s rated for 12V. Maybe they can handle a little more. I might give a go at seeing weather they can handle 16V for a 4S configuration (XHP-35 HI), but a buck driver would probably be a better solution.
Jtm94
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Yeah, The Miller, that’s the idea. Up above Mike C said, “For 2S lights the A705NGT might be of interest. They are basically 7135s that are rated for 12V.”
This is getting me excited for all the Q8 modding to come.

Texas_Ace
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Schoki wrote:
Texas_Ace wrote:
I am actually working on another project where we are trying to drive 15A+ on a buck so a new option would be nice.
And what IC did you choose for your project, and who is working on it with you?

Del and I have been working on a project for an un-named manufacture for an un-named light that would require over 30A of power. We settled on 2× 15A drivers in parallel as the best method to reach that.

We have been working with the LM3404 right now, it is a little undersized but should work with the right PFET. The larger options we found all had issues that made them impractical for flashlight use.

The ISL8117 looks interesting though, I am going to show that to Del and see what he thinks. We had not seen that one yet.

Seems like we saw the LM25145 at one point but I will have to check. We have looked at too many to keep track of lol.

Schoki
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LM3404? This IC has an integrated FET. Do you mean the LM3409 instead?

Texas_Ace
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Opps, sorry, yeah, the LM3409.

Schoki
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what are your goals on input and output current/voltage ripple?

Texas_Ace
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Schoki wrote:
what are your goals on input and output current/voltage ripple?

The overall setup is 6S6P input with an 18V LED output with a total current draw of ~30A.

Ripple should be as low as is practical, we are working on the rest of the setup and going to kind of see where the ripple ends up. Looking like it should be around .25A or less from early calculations IIRC. The real issue has been finding a PFET that will work.

The project has been on hold for a little while now while the manufacture tries to find a PFET that they can source that would work.

Schoki
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6S6P? Probably need a backpack for that Wink

Texas_Ace
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Schoki wrote:
6S6P? Probably need a backpack for that Wink

Lets just say that this is not a light that will be an EDC choice lol.

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Seeing how TomE gets 27 klm with triple XHP70.2 in MT03 I really wish to do a similar thing with Q8.
Having quad LEDs it should certainly do 30k. It would be even better when running 12v. But there’s no XHP70.2 PCB and no suitable FET+linear drivers…..

Texas_Ace
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I don’t think you realize how hot the Q8 would get at 30k lumens. Going off of past numbers for the XHP70.2 at those kinds of outputs.

You are looking at around 120 watts per LED.

So around 480W total output.

To put things into perspective my SRK mods that are doing a mere ~150-200W get hot in about 30-45 seconds (think BLF A6). With 2-3x the heat you are literally talking about 10-20 seconds to get hot.

In addition to this, most cells can not support that much output.

Most cells are only rated for a max of 20A with a few reaching 25A. You would need cells able to support ~35A each to power this safely.

So while yes, it could technically be done. Is it really worth it? That is up to each persons wallet I suppose.

I can say I rarely use my 8x xhp50 SRK as it simply gets hot too fast to be useful, even if it makes 17k lumens. I prefer my 10-13k lumen SRK’s that are much more reasonable.

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I have never used anything like that, so maybe I don’t realize. But it sounds like my D4’s bigger brother. I have the hottest variant, use it with VTC6 and ordered VTC5A because I can’t have enough.

Jtm94
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My novice thoughts are that using 4x XHP50s is about as much light as you can get out of the Q8 practically. I got my first XHP50.2 light and it does about 2000~ lumens from 6-8amps and isn’t busting a sweat in terms of heat during extended running. In the long-term I do not see my Q8 being stock forever(not that anything is wrong with it), but I am on a unending quest for more lumens. Though 20A per cell in a 4× 18650 light doesn’t sound unappealing… I’m not ready to put that many watts in my hand just yet.

hank
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> that many watts in my hand

Yeah, the main mod I’d like to figure out is a way of handling the heat.
Not that I want the flashlight to end up looking like the International Space Station, which has its huge heat radiator panels (almost as big as its solar photovoltaic panels, but aimed differently)

But there’s stuff, like: https://www.qats.com/Products/Heat-Pipes

Quote:
A heat pipe’s wick structure and embedded liquid enables it to produce a very high heat flux transport capability, which can be 10-20 times higher than the equivalent diameter solid copper pipe. The application of heat pipes in the thermal management of electronics has increased considerably in recent years because of PCB space constraints and increasing component and power density.

Pre-made, many sizes and shapes, copper with distilled water inside, ready to be soldered to a heat source at one end and a heat sink at the other….

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Just got in some new batteries, thought I'd test them in the modded Q8 from round 3, and show some base Q8 stock measurements vs some relatively simple mods as noted:

The tail PCB was modded to build in a high amp loop for measuring with a clamp meter, plus bypasses added. The blue wires are teflon coated, i think 20 AWG:

 

This is the stock 18 AWG wires cut back, the soldered up to 16 AWG for the longer run to reduce resistance:

With 4 XPL2's in an early Q8 prototype, I measured 26A using the same wire loop setup, and output was higher even with V5 bin XPL2's.

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