I have been away from the forum and flashlights for a while now. Had to deal with some health issues.
I want to build my second flashlight and I have a Convoy C8+ M21A host to put it in. I’m still not smart enough to understand some of the discussions about LED’s and drivers. I am hoping you all can give me some good recommendations for the driver and emitter. I’m going to purchase from mountain electronics because I don’t have the patience to wait for overseas delivery.
My first build has an SST-40 in it and I thought that I would try something different. My main goal is still to have a long thrower. We use them to spot poachers.
I can solder fairly well and can follow instructions well too.
This is what I have in my cart right now. FET + 7135 Driver - 20mm - MTN-20DDm w/guppy3 and Luminus SST-40 N5 5000K
My other SST-40 is 6500k and so I want something else. Any help will be great.
M21A takes a 20mm driver and 20mm mcpcb. So you’ve got that down. C8+ takes 17mm driver and 20mm mcpcb.
Next you want to compare the driver output to the stats of the emitter. If the LED is 3 volt 6 amp led. You don’t want to get a 3v 10a driver. Or a 6v 6a driver. You’ll fry the LED.
Btw, SST-40 5000k is probably not going to look great. They tend to be very green on lower settings. For a thrower, you’d be better off with an SFT-40. The tint is much better and it has a smaller light emitting surface which makes for a better thrower. If you do stick with the SST-40, get an OP reflector. SMO for the SFT-40.
That’s very helpful. With the emitter, I kind of new that SFT40 would probably be better. I will look on the website again and use the information you gave me.
I have a these parts on hand. The were sent to me accidentally and they let me keep them. CREE XP-L HI V2 3A LED on Noctigon 20mm MCPCB w/guppydrv FET Revs 2- 20mm. How well would this combination work with C8+ M21A?
Thanks for the correct information. It would explain why I couldn’t find it on the Convoy website Lol. I keep records for all my flashlights for insurance purposes and I will need to change it there.
That sounds like a good idea. Thanks for the help, I really appreciate it.
A while back I bought a rechargeable soldering iron that will make it a lot easier to solder the leads to the board. My dad has about 2,000 feet of wiring and I used a lot of it to practice my soldering. I never got great at it but I’m sure better than I was two years ago.
This–the SFT40 is a very substantial upgrade over the XPL-HI: more efficiency, more output, more throw in the same beam profile.
The SFT40 will also maintain max output a lot longer than XPL-HI, due to the lower forward voltage. The only question is whether a FET driver might let through too much current and fry the LED–could someone chime in on the FET+SFT40 combination? A sure way to avoid this is to use a high-capacity rather than a high-discharge battery.
Great thank you. I might do two lights. Will this driver work with SFT40 FET + 7135 Driver - 20mm - MTN-20DDm or should I get the one I mentioned in my last post.
Issue with MtnElectronics is that they don’t have 3V buck drivers, which result in much better system efficiency than FET/7135 drivers and is compatible with any battery without the risk of frying the emitter. AFAIK only Convoy sells these drivers that are compatible with C8 or M21A.
But as long as you stick to a low-drain battery, the FET driver will work. With or without 7135 doesn’t matter, just get the cheapest.
There was a misconception that 7135 makes low modes more efficient, but it just moves the efficiency loss from the emitter (due to diminishing returns at high current) to the driver (due to burning off excess voltage as heat). Also I’ve found the FET+7135 drivers more fragile than pure FET–I’ve fried two FET+7135 drivers from MtnElectronics for no apparent reason (in a C8), but a FET-only driver from them is still working after almost a decade.
Damn, wish I had known then. Those drivers are pricey!
In fact, even if you buy just a 8A Convoy buck driver and pay for the full $5 shipping for orders under $5, it’s still cheaper than a single driver from Mtn, without shipping! Might as well get everything from Convoy if you don’t mind 2 weeks shipping.
That’s great information and I will definitely get the pure FET driver. I am going to order some things from Convoy. I looking at a Convoy 3X21B or something from the L series.
These two lights I’m building are for my two sons.
Thanks for all the help. You saved me time, money and headaches and I’m learning more.
If you want to order from Convoy at all, just skip MtnElectronics entirely because Convoy has basically a better version of everything Mtn has, but also cheaper. Mtn used to be the go-to place for US-based flashlight enthusiasts, but times have changed and they haven’t kept up.