Hi all. So I've been working on this since October off and on and finally got it done tonight. I don't normally put my projects on here, but I thought I'd share it. It's not pretty, but I didn't intend it to be. Was just looking for a fun project to make an old light live again... It started out as a Lumilite 4700 "krypton" floating flashlight that takes the 6V lantern batteries, like you get from Walmart or something. I got it from the Salvation Army half-off Wednesday sale for $1.50. It was in okay shape. It didn't work and the rubber boot to the switch was disintegrating. I discarded it because it wouldn't handle what I had in mind for it. I had thought of doing a XM-L2 or maybe SST40 mod, but decided against it.
You might notice the digital voltage display. There's a reason for it...
That black plastic post is there for a reason too... I decided against the XM-L2 because I went with this!
XHP70.2 6500K. It's a 12V model. Running off a home-made 3S li-ion with a boost/buck driver. Currently it's at 14V and 2.6A. I won't go higher since my driver gets too hot! The LED is fan cooled on a heatsink from a Pentium 3 CPU. The back of the reflector is a solid piece of sheet steel I ground and polished so it draws away heat too. Overheating is not a problem.
Here are some pictures of it running. The output is variable with a pot since at full whack the batteries won't last long and it's way to bright to use indoors at full power. The amount of light is insane. The camera doesn't come close to how intense it is. It's as bright as my 100W COB build and throws tons farther. I will show you pictures of that one too if everyone wants to see.
Indoors with all lights off. The far wall is probably 20 feet away.
A full volt of sag at full power. Poor batteries.
No outside shots yet. It's late and I'm tired, so I'll try to get some tomorrow night.
Glad you all like it. A little blood and sweat went into it. Getting a 70.2, heatsink, and driver to fit in there wasn’t easy. My other lights don’t have removable batteries which makes them easier to build.
For sure. The pot is mounted to the driver board. It controls the voltage because the current limit is set so it will voltage limit when it reaches the current limit. I have another light that the pot is remotely mounted. It’s not easy to get everything to line up!
Thanks! Everything is pretty much custom made. I found there weren’t many off the shelf parts I could use besides switches and electronics. It took a long time, several hours to get it that way. The reflector wasn’t designed for an led, much less a multi-die led. Lots of grinding, sanding, adjusting, centering the reflector to get the spot the right size then focusing to get it just right. It’s worth it though. I don’t know the exact output. I was shooting for 5000-5200 lumens. I can guess it’s around 5000? My 100W COB light is around 5500 and this is easily as bright and throws exponentially better. More efficient too, less heat. It’s so bright it hurts my eyes when I shine it on a white wall a couple feet away. I’ll post pictures of my 100W one later as a comparison.
It’s pretty well sealed, save for some small gaps in places where parts don’t fit perfectly. There is enough space inside the case to keep the temps good. The xhp70.2 has a high tdp 105C and I have really good heatsinking. Unless the fan quits, the batteries die before it overheats, or the driver pulls the plug for over temperature. My 100W light is another story!
Here's my 100W COB light. I call it the Road Warrior. This one started as an Ozark Trail 6V spot light. There's actually 2 lights in there. I used the bezel and reflector from a different 6V light. It's gone through at least 3 revisions to fix unforseen issues with the original design...can you guess what they were? ;)
There's a big COB emitter behind that aspheric lens.
It needs lots of cooling! The reflector is separate from the rest of the light so exhaust air can escape. There's a 80mm case fan behind a heatsink that went to an Intel Core2 Quad Q9550 95W CPU. It's barely adequate.
cooling air inlets.
The battery is built in. There's the charging and balance ports with the volt meter display.
That's full power. 34V at 3.2A. It is variable output. The emitter runs off a 250W DC-DC CC-CV boost driver. The battery is a 4S2P of my design with a 20A BMS. The batteries were never meant to take 10A of draw so the 4.4 Ah pack lasts maybe 10-15 minutes if fully charged. I will get some new INR li-ions soon. The voltage sag is 3V at full power. It generates a ton of heat. Yes it's bright. It's a flood light, but throws maybe 50 yards? My wife hates it.
I really like how you’re breathing new life into these 6V lanterns - great idea to use that extra space to fit in a cooling setup.
And this is a creative way to repurpose stock CPU coolers! I’ve got a pile of those still lying around, unused…
Thanks. They’re great for leds, cheap and easy to mod with lots of room inside inside for supper stout cooling sysyems. I overdrive my emitters a bit and need the extra cooling. I built the xhp and COB lights for around $30 US each. Just lots of labor.
The only issue with these is there’s no of the shelf pays like for Convoy, Surefire, Maglite etc, so you have to make your own mounting hardware, mod the reflectors, mount electronics, batteries etc. I think they just look cool and need love. I don’t see them getting modded much. Maybe I will inspire some folks here?
I thought about doing one. If I do, it's going to be a traditional type light. I'm thinking I'll name it Lazarus...I found it in a paper bag with some old crappy tools that got left behind by a contractor that never came back for them. Alright, so it's old (maybe 12 years old?) dirty, broken, doesn't work, but it's rock solid, heavy, and sturdy. I think it's a 2D size. I'm planning for a 16mm 70.2 6V 5000K. Will use two 26650 and a 22mm buck driver with a user interface. I've already lengthened the body and came up with a custom end cap to make room for the cooling solution. It's my most ambitious and expensive project yet. I've already spent more on this than the others I've built and it's not even started. Probably start sometime in the Spring? I need a tool to make custom parts though so I'm saving for it before I can start. What do you all think?
