So some of us are stuck at home due to the Coronavirus and what not and I get cabin fever really bad, so I figured it's a good excuse to start a project I've been pining on for a while. I love the BLF GT concept and wanted one, even more when the BLF GT70 came out. What a bonkers light with a single emitter! Then I saw the price...north of $350. Boo. My wife won't let me sell our son, and I need all my body parts, so I thought, hey why not build one (or one like it). It's a work in progress so check back for updates. Obviously it's based on a direct-driven xhp70.2. The emitter is a 6000k xhp70.2. I decided to do 12 volts for this one since it keeps the current pretty tame (easier on the batteries and wiring). The power source is a 4S2P lithium ion pack of eight VTC6's (can't think of a better way to spend my stimulus check). It will have a BMS and all that.
The driver was tricky since I wanted one that did 4S input and was guaranteed to give crazy output. So I went with Richard's FET+1 26mm driver from Mountain Electronics with Bistro.
Cooling the thing was tricky too since I'm dealing with close to 60 watts or more. My host will be plastic so I'm limited to a heatsink and fan arrangement. For the cooling, I went with an old Intel stock cooler for a high end Core2Duo. It's huge and can easily handle 120W or more. It weighs a ton. I removed the fan since I'll be using a slim one.
The host? Nothing less than the halogen (formerly) powered spotlights. I found this one in the thrift store for like $1. It's got a rotatable handle and a stand (I took it off temporarily) and it's huge with lots of room inside for a heatsink and big battery. It was powered by a 6V lead acid cell that someone took out. Not really waterproof, but that's okay.
3000000 CP? Woah.
First was figuring out the electrical connections. I used my experience with the last project and built a driver holder out of some copper sheets salvaged from laptop PC coolers. I cut them out and soldered them together. I drilled out 2 parts to make the top part and the "shelf" or ground ring that the driver sits on. The negative from the battery will solder to it somewhere.
The driver fits into the bottom part of the heatsink that's hollow. It's a pretty much perfect fit. It will be secured with screws and extra mounts later.
This is the first test of everything. Wires will be 18 gauge for the battery and LED. Yep. It's bright. I'm using an old battery from the 100W flashlight project made from a mix of really tired laptop pulls so I know it has more to give. It's so bright. I can't shield the light without it burning my hand. The alligator clip that connects the driver gets hot and the plastic cover on the clip gets soft and smelly after a couple minutes of turbo. It easily gets the heatsink up to 135 degrees after 3 minutes of turbo (before the stepdown). That's like 500 grams of aluminum and copper heating up. The driver doesn't hardly heat up at all though. I'm excited to see how bright it gets with proper batteries. I still haven't figured out the firmware though.
That's it for now! Still need to dig into the host and figure out mounting the cooler and fabricobble the reflector. Proper reflectors for this are stupid expensive, so I'll make one.
Stay tuned for more.