Nope, unprotected. The charging port of the driver is directly hooked up to the negative and positive of the battery, but I’m guessing the PCB traces couldn’t handle the current.
Quote of the year so far !
Ryan, you could rig up an IP camera so we could watch the event live !
That’s what’s called a poor man’s fuse. So there is some protection against over-current after all.
Wish I could drop by with a 100ft extension cord. Lets see that cell resist when we have unlimited power to throw at it. 
Steal some nichrome wire out of a toaster and see if we can get the light up to 160°C.
Sorry, my little brain is having a hard time understanding where the PCB ( printed circuit board ) is ?
This flashlight has a charging port which ryansoh3 was using. Thats where the pcb is and the circuit trace that might have burned.
That makes a little more sense to me but he said “the charging port of the DRIVER”
Google Hangouts might be fun, haha. 
Starting to sound like those crazy Youtube channels where they toss things into a microwave to see what happens.
Sorry about the confusion. The driver has an integrated charging port that you can plug in a DC jack into. The port is directly connected to the battery, so whatever I pump into the DC jack flows through the battery too. Here’s a photo of the driver, hope this helps.
The black box on the bottom is the female DC port.
Here’s the video of the first try, notice how the voltage jumps back up from zero at around 3:45.
be careful as you do this, and will be watching for updates!
Aah, I get it now. Thanks for explaining to me.
No problem.
There’s the culprit; the upper spring shriveled up due to the heat. I’ll touch up on the contacts (copper braided springs, switch bypass, etc.) to minimize the resistance and I’ll give it another go.
Copper braiding springs for a one-time five minute performance shows some true dedication! :-)
Haha without it, I doubt we’d be getting anywhere! I’ve managed to reduce the resistance to 0.349Ohms, but the cell’s IR is 0.079Ohms, so we still have fairly high resistance somewhere, maybe the PCB?
The 1m mains wire I’m using is 0.75 sq. mm, which translates to 18AWG. Double the length (+ and -) and we have a theoretical resistance of 0.041Ohms. That means we still have the majority of the resistance somewhere else, but we’ll see how this goes.
I’ll go through with the second trial in a couple of hours.
woudl be quicker to just have the two wires direct to the cell inside the light, then run 25 feet of # 14 2-wire to a 12 volt car battery in a safe area. connect it direct and wait a few seconds. a 12 volt Lead acid battery pushing 20 - 30 amps direct through to the LiIon cell should force it to vent quickly from the current and voltage surge.
Yeah, I tried that a couple of months ago with a cell phone battery but it still wouldn’t vent. Puffy, but still didn’t work.
I think Pregulla said in post #30 that Samsung 18650s are tested to withstand a 12V voltage source. Not sure if it was current-limited though.
The nice thing about the iCharger is that it boosts the voltage up and up (around 21V last time) until the cell vents in NiMH or NiCd mode because it’s in constant current mode. Li-ion cells are surprisingly robust, yet we still hear of li-ion fires and explosions. :~
I’m a bit worried about your safety, if it explodes it may be quite a big explosion. Don’t feel like it’s enough shielding
Take lots of care!
maybe run the LiIon cell down to 1.5 or 2 volts,. ( below its safe voltage, then surge it with two 12V SLA batteries in series, 24 volts.
Thank you, I hope the camera and the phone survive. As for me, I’ll be taking cover around a concrete slab so I think I’ll be fine.
I think that’ll definitely make the cells vent, 24V is a lot of voltage, haha.
I’ve tried the experiment a second time… and about 15 minutes in, I got another open circuit. 
I’m leaving for school tomorrow morning, so I don’t think I’ll have time to do it a third time. But, I can solder up some leads to the 18650 cell and make it vent with a very high certainty, if the cell’s not the one that’s the problem.
I’ve recorded a video, but I don’t think it’s worth sharing, as nothing happens again.
Edit: Good news and bad news.
The bad news is that the cell’s the one that’s gone open circuit. I’m reading 0.36V, but I can pull or push any current into it, meaning something’s broken inside. I don’t have a replacement 18650 unfortunately, so this experiment will have to wait.
The good news is that the flashlight itself seems fine, so I’ll just be able to pop another cell in start the experiment right away. Hey, at least Tesla’s cells are “protected” against overcharging.
Are you done abusing that poor Warsun yet? Maybe you can do a host giveaway with what’s left when you are done?