Okay so here's my 100W flashlight I've been promising to show you guys and gals. I had to tear it down to fix the balance port socket because it detatched itself from the flashlight body making it impossible to charge. I had been putting it off because taking this thing apart is a bear, but the teardown is necessary because I need to get to the battery.
I built this starting in winter 2017. It is my first mod ever and I did it mostly because I've seen plenty of 100W light builds, but none in an actual flashlight host that was self- contained (no external battery). This was a monumental challenge and I had no idea what I was getting myself into! It took me a solid 5 months to get to the first prototype, then another 3 months of refining to get what you see here. All I'm all, probably over 600 total hours in this over a year and a half.
Here you go... the host was an Ozark Trail "floating" lantern with those big 6V batteries.
Up front is a housing with a reflector inside. The gap is to allow exhaust air to escape out the front.
Coool air is drawn in from the top under the handle and on the sides. That knob is the adjustable trimmer for brightness control since this doesn't have "modes."
It needs a lot of cooling air.
The first version didn't have the front housing with the reflector. This was necessary since it was way too floody for my tastes (a lot of wasted light) and the escaping light from the side of the protruding lens was blinding people. You'll see what the original setup was like later.
The switch isn't the original. It's a 12V 15A rated unit meant for a car. The original died a quick, sparky death since it wasn't meant to handle 10A!
On the back is a voltmeter I stuck in the handle.
Alright, on to the teardown!
First was removing the screws holding down the front bezel. Once they're off, the whole front with the reflector can be removed.
This is the heatsink. It's from a stock cooler meant for an Intel Core2Quad I think. Anyway it's meant for a 95W processor. It's the smallest one for that TDP I could fit inside. It works pretty good. It does get mighty warm at full blast though!
I wasn't going to take off the reflector since it's a hassle to get it back on, but I did it for you all 8)
The first version only had that bezel on the left. The aspheric lens pokes out a bit and was blinding people staring near it when running. Plus it tightens up the beam a bit for more throw. It's still really floody!
This is the heatsink with the emitter and its reflector cup with the aspheric lens.
Underneath is a 100W rated COB emitter. They're designed to be run at 32-34V and 3A. I got mine on eBay for like $14. It's been rock solid. No dead LEDs, etc. They all light up evenly. I'm slightly under-driving this one. You'll find out why...
The fan is a 70mm case fan blowing over the heatsink out the front through the bezel. I've added some current- limiting resistors to keep the fan speed down so it's not crazy noisy.
Here's what's behind the fan... the guts! It's a battery, a bunch odd wires and connectors, and the 250W constant current, constant voltage boost converter. I got it for like $11. This is the second one because the first one failed. It's got 2 trimmers to adjust the current and voltage limits. This is critical to regulate the current for LEDs since they have such low internal resistance. Small changes in voltage cause bug spikes in current! I'm limiting the voltage with the trimmer to adjust the output. The current is limited with the other trimmer. The input wires are 16 awg and the output to the led are 18 awg. The inputs have to handle the 10A coming off the battery to the switch.
The battery is my own design 4S2P made from laptop batteries. This was the most I could fit in there. It originally had a 3S2P, but I switched it to a 4S due to the stain on the batteries. Going to 4S helped a little, but the boost driver is pulling 10A from the batteries. The BMS can handle it, but the poor laptop cells are suffering pretty bad. On the highest setting, I get a whopping 45 seconds of run time before the bms pulls the plug due to one or more of the series cells dropping below 2.8-2.9V due to the sag. When I charged th4 battery, you can see which cells are compromised!
Series cells 3 and 4 are low. These have recovered somewhat but they were down to all of maybe 3.4V before I started the charge.
ls 
I thought I'd show inside the handle where the voltmeter lives...
That's pretty much it. I just needed to fix the balance port and plug...
but hoped you liked the teardown.
By the way, here's a shot where it was running at full power.
I'm thinking I might but some new batteries and make a new battery pack that will give more than 45 seconds. Which do you recommend? I'm thinking 18650GA or maybe 30Q.
Thanks for looking!
