Switches, Drivers, Cooling Questions

Hello. First off, I’m not really a noob at the LED light hobby, but I’m venturing off the beaten path a bit with my pending project. I have built 2 other LED lights-a 100W COB handheld out of a Rayovac 6V lantern battery type light and a roughly 8W version of the same overdriving a 5W LED. I am working on two others now, one like the first two, and now a torch type one made from an an old Energizer 2D light. I’m going to be using XHP70.2 emitters for these- one on 12V 3S2P lithium battery pack, the other on two 26650 in series. I am using a 60W CC/CV driver for the first, but that is way too big to fit the other, so I need a driver for the torch one. It seems that good information on these drivers is hard to find.

I’ve looked all over for a good one, but all I can find are the generic China special 26mm drivers and the ‘FX-30’ drivers. I hear they all suck and are apt to over and under-drive the emitters. I did find one from AdventureSport that seems good, but it’s kind of expensive. I figure the emitters like to be run at 4.5 to 5A on 6V and 2.4A on 12V. Anyone have suggestions on reliable drivers?

Also, I need ideas for switches, since the stock ones won’t handle the current.

Any help is appreciated!


Contact Lexel for the driver.
ADDED: For 2s https://led4power.com/product/ld-b4hv-2-12amp-2s4s-multi-cell-17mm-constant-current-led-flashlight-driver-external-mosfet-support/ will also work, though you’ll need to cool the FET somehow.

If you can afford to install a ∅22mm driver, the H2-C at Kaidomain is a great option. A lot of related information can be found in the thread Buck and Boost Drivers, Testing, Modding, and Discussion. Stock comes with an R050 sense resistor. Stack another R050 above it and you'll raise maximum output to nearly 3A, with gradual 30 second stepdown to 2A after the first 30 seconds. This of course for 4S (“12V”) emitter driving with 2S battery input. Handled up to 2.5A efficiently and without trouble in Jensen567's tests with 2S input, so take this with a grain of salt anyway; I think it would handle 3A maximum (R025 sense value) without problem too.

With respect to the emitter board a Sinkpad 7070 12V or 6V will do, just bridge the R1206 pads for 4S “12V” driving. There may be other sources for those boards.

Cheers :-)

Great suggestions! I’m trying to avoid a boost circuit since from experience with my 100W light heat management is a concern as it generates insane amounts of heat even though it’s attached to a fan cooled heat sink from a PC. My battery only lasts 15-20 minutes on maximum brightness. I used the same setup on my other light so I can run it nonstop without overheating.

I’m leaning towards direct drive. I am thinking that AdventureSport’s driver is my choice https://asflashlights.com/-diy-parts/75-10-amp-capable-17mm-led-driver.html since it’s DD and pre configured for the application. Now since the light body is made from plastic, I’ve thought a lot about cooling the emitter. It will be on a copper sinkpad on a circular aluminum cooler with a small 30mm PC fan. I’ll find a switch to use next. I’ll run a wire from the negative spring in the bottom to the negative input on the driver. I’m still trying to figure out the positive connection. I bought a old 3D Maglite for $1 at the thrift store I will use for other parts if needed for like spacers and what not.

Any other suggestions on setup and other details are helpful!


Well Sirstinky, I do not believe you have taken the time to analyze the H2-C's data. Driver's efficiency is above 90% even if going high power when 2S input. And pretty sure you could set a couple in parallel just in case.

A regulated setup will net you constant brightness without pulse width modulation at all power levels, a MOSFET misdriver can not. And if you care about cooling I'm pretty sure you can heatsink the drivers and/or attach small fans over them.

Cheers ^:)

Good points here. The less you boost voltage, the higher the efficiency,so there’s not much difference with the input versus the output. Say you were taking 6V and getting 12V, then there’s no way you’d get 90, maybe 85 or less depending on the driver itself. With my 100W light, I’m talking 16.8V and boosting it to 34, so yes, you’re going to get heat. On another note, do you have a suggestion for a switch to use? It has to be small because I’m short on space. :slight_smile:

Thanks again!

That driver looks great and can handle serious power, but I’m looking for a drop-in driver that’s already been configured. That’s why I’m now leaning towards AdventureSport’s driver. From doing more research and pricing, it looks to be competitive in price to other high performance driver boards. Next step in figuring out how to connect everything! My host is funky in that it unscrews from the middle not the bottom. I’m thinking of modding it to be able to get the batteries or from the bottom, but that has it’s own challenges!

Thanks for the help

I understood you were looking for a driver for the “torch one”, the one on two in series 26650s. What is the amount of power you aim for, and the available host space? Your provided information looks confusing to me.

Cheers ^:)

Sorry for the confusion. For the torch I’m looking to run the xhp70.2 at 4.5A on 6V. I’d like to get 3000-4000 lumens from it. For the space, I added a spacer in the body to make room for the 26650’s. It was originally a 2D light. I have about a 2” space from the bottom of the reflector to the top of the batteries and probably 1.3” of that is going to be filled with LED emitter, mounting hardware, heatsink and cooling fan. It’s a work in progress for sure!


Well, not gonna go on about this. The above table shows the H2-C's excellent efficiency even with 30mΩ sense resistor (stock R050 + R075), the driver is actually quite capable because its boost IC input current limit is 17A (!). Kaidomain does customize some other products, maybe you could ask them to send you an H2-C with an additional R050 atop the stock one for R025 sense resistor value and nearly 3A of current before stepdown and 2A after, at “12V” (this is 6A and 4A at “6V”). One of my favorite drivers suffice to say.

But well, you know better your stuff. Take care and be successful. :THUMBS-UP: