17mm driver, XHP70.2 build?

Hi
I am building a Convoy M1 for my shotgun light as its the perfect size.
The driver needs to be 17mm to fit and power the XHP70.2 6V.
I would like a driver that can push the XHP70.2 to its limits as it will only be used in small burst so heat will not be a problem.
All I know is its a 6v LED so I will need a boost driver and that’s about it. So what else am I missing? Anybody got any suggestions?

thx

Mountain electronics makes a 17mm boost dr9ver. It’s not cheap though.

The issue you might find with a boost driver that can push a XHP70.2 LED to it’s limits is that it has to have a huge inductor which, from what I can see, will not fit in the driver space of the M1.

I’ve been playing around with boost driver design for some time and for those kind of currents I’ve used the XAL7070 inductor, it’s 7mm high which I think is just a bit too high to fit in the M1. If you lower the current the 3mm high XAL7030 could be used, it will fit. I’ve not used other inductors than Coilcraft, perhaps there are more suitable out there, I haven’t checked. My design is still work in progress.

MTN has a 17mm boost driver with lower inductor (which means lower output current). It should fit: 17mm MTN-BST2 Boost Driver

Thanks guys if I go that driver I should select option “10.5A IN | 4.2A OUT” right? I have not ordered the host yet so do not know how much room I have. I am just getting the parts list going.

Does a Direct drive / boost driver exist? If so would that be a good option? I only need a one click turbo setting no other settings needed.

I only need 2-5 second burst of a floody beam no throw needed.

Should I be looking at something else maybe? I just don’t won’t a light any bigger or heavier than the M1 size.

You could go with a 3V XHP50.2 instead. You can just use a simple FET driver and it will draw more than 15A with a good cell. That is likely more output than you could get with a 17mm boost driver and the xhp70.2.

Now that’s an idea. I love the “more output” part. I will give that a go I think. Best place to find a FET driver ?

Mountain electronics makes nice fet drivers. They’re 7135+fet or just straight fet. I have several and get 14-15A on a vtc6 on a 50.2 3 volt. Or you can see if Lexel has one (he has been absent of late). TaskLED also makes boost drivers.

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My thought exactly. :+1:
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XHP50.2 is likely a better idea overall since you won’t have to mod the reflector at all to fit it. I honestly think you could just run it driverless with the right cell if all you want is max brightness for a few seconds at any given burst. I’ve done this many times, and that’s exactly what I did for my shotgun light many years ago (but w/ a 6V gen1 xhp50 and two 18350s). It was a 1st gen Convoy C8 and I made a homemade FET tailswitch that ran off a 2032 and a remote pressure switch. The donut hole actually provided a perfect sighting point too! Tested it between 5 and 20 yds with 3” high brass 00 buck and they all hit center with a spread about equal to 1/3 of the hotspot. I’ve recently torn that light down and actually was going to rebuild with a newer host and maybe a Luxeon MZ in a M21B or similar.

No. Direct drive basically means connecting the LED straight to the battery. If your LED works with that voltage, then you wouldn’t need a boost driver.

Agree with this, it’s a better option, at least for the M1. Although I can get over 9 amps to a XHP70.2 with my 17mm boost driver, it requires that huge inductor that won’t fit into the M1. FET drivers are a lot cheaper too. You could also try the simple driver-less option suggested by JaredM. If you don’t need low voltage protection and all that stuff, just hook it up without a driver. With the 3V XHP50.2 you can stick to a single 18650 cell.

I went with the M21B 21700…3v XHP50.2 Heavily modified….

It works on my AR10 .308 SBR…

M21B next to my M1 Quad…

Go with the 3v 50.2….your gonna like it alot!

Thanks for all the help guys this place is just great. XHP50.2 it is done and dusted its on it’s way.

I ordered all the gear from Mountain electronics. I went with the FET + 7135 Driver & guppydrv DUAL Firmware

I ended up going with a driver. In the end having a light on the shottie that I could run longer if needed made more sense. That donut hole sounds like a great idea.

Your 9 amp XHP70.2 boost driver sounds interesting what host does it fit in ? and do you sell them or make them just for yourself?

I downloaded it and had a look but this is over my head I have no idea what it is.

Glade to hear you highly recommend it. I went with the exact same set up just in the M1 format. I went with the M1 because all my mounts will not hold the M21B and I wanted to keep the weight down.
I also have a M21B and love it. AR10 .308 SBR wish we could own them down here very nice.

I haven’t squeezed one into a host yet, it’s still under development. I have a thread about it here: V4 of my B17 17mm boost driver, success finally!
I’ll at least make it available as DIY but I don’t know about selling them, at least if I have to build them myself because they would end being rather expensive to make it worth the time.

Thanks for all your help guys the M1 is finished very happy with it. Very bright with a good hot spot. I did swap the XHP50.2 6500K for a warmer one 5700K I got from cutters as the first one I fitted was to cool of a tint.
I like it that much I am thinking of making another one this time using the M21B.