Here’s a short video that I did of overcharging a li-po cell. Please do NOT try this at home. 
I did use a copyrighted background song, so the video may be blocked in mobile browsers. :~
interesting, the explosion happened faster than I thought it would. (I thought it would vent for a bit)
thanks for the video.
Wow. reminds me of when we blew up some Electrolyte Caps with a 12 volt car battery charger by reversing the polarity.
Wow. Your instruments and battery were within the throw radius, lucky it threw its guts in the other direction or you’d have gotten some on you.
Nice demonstration. I like your (second to) last line in the video.
Can I make a request for the next one?
18650 closed inside a cheap flashlight. It would be good to show people who think cheap junk 18650s might be ok.
Warning to random people reading this thread, flashlight must be placed inside a small hole in the ground, you must be away from it, behind a solid wall & prepared to deal with it if it appears to do nothing. But really, most should not try it.
Poof!
harharh 
Thanks for the comments guys. As you can see, you can tell that my summer break is slightly boring. 
I did previously make a video that I haven’t published, and that cell vented and flew across the roof instead of bursting into flames. I thought this was more exciting though.
Yes I agree, I didn’t expect the battery to come apart. Next time I’ll have to make the cables longer.
I’ll see what I can do.
Any cheap flashlight that you guys suggest or donate to the cause?
ryansoh3
I haven’t seen videos of a flashlight actually exploding, only pics. it would be great to see one (but done very carefully, safety first)
We only need a mad scientist, preferably from seoul, and a battery and host (preferably ultrafire)
I think we can collect some money via paypal to send someone a crappy flashlight-batt kit and some safety googles
That’s an interesting idea, I have some crappy 18650’s I’m willing to try out and I do have safety goggles as well.
Thanks for the post & video. If I may make a few comments? Personally, no background music for me. I like to hear the sweet sounds of exploding batteries in their full High Def Dolby Stereo HTX Digital IMAX Surround sound! And finally, blow the car battery up next!!! 0:)
Were you doing this on a rooftop?
> cell vented and flew across the roof …
> I didn’t expect the battery to come apart.
> Next time I’ll have to make the cables longer.
You need to make better plans than that to protect other people in the area.
Are you cleaning up after yourself?
The electrolyte left behind on the ground, and boiled off, and the combustion smoke products, are toxic and going to stay toxic — you can’t easily dilute this stuff down to safe levels with water.
http://www.nrel.gov/education/pdfs/lithium-ion_battery_safety_hazards.pdf
“when the electrolyte is combined with water, there is the potential for hydrofluoric acid to form an extremely toxic and corrosive substance. To learn more about hydrofluoric acid, visit the following link to the Centers for Disease Control’s website:
http://www.bt.cdc.gov/agent/hydrofluoricacid/basics/facts.asp …
The only extinguisher that will work on a Lithium-ion Battery fire is a Class D Fire Extinguisher or Dry Sand or Dry Table Salt.”
If done in a flashlight you would have open parts for wiring to get inside, i suggest using a light with built in charger
Yup, this was done on a rooftop and I certainly have cleaned up the remains because this is an apartment.
Not as immaculate as how Hazmat officials would have done, but pretty well done in my opinion.
Nice video.
If you are thinking about more experiments, I think it would be cool to see how flashlight goes poof when using it with mixmatched lithium batteries. Just remember the safety.
(my emphasis in bold) Redoing this inside a flashlight makes very little sense to me.
- A flashlight without a charging circuit will not cause a cell to do this, period. Dead shorts do not cause this behavior, and that’s the worst thing a non-charging flashlight could do to a single, solitary, cell.
- Even the most terrible charging circuit found inside a flashlight simply won’t be able to do this. ryansoh3’s iCharger was dumping 40+ Watts into that little LiPo cell with the pop coming at 30 Volts. The cheap flashlights in question would have a USB power supply capable of maybe 10 Watts at 5 Volts. I’m pretty confident that even a direct short of the charging circuit (putting 5 Volts at 2 Amps to the battery) will not do this to a battery.
ryansoh3 didn’t misrepresent his video at all - he overcharges a battery and says so! But this concept of “overcharging a battery to show the danger of cheap batteries” is played out. It was never valid. Quality cells fail in exactly the same way in this scenario. All this shows is the danger of (imaginary) cheap high-powered chargers.
If we want to show people the danger of something, we need to do it in a way that actually represents the problem.
I agree with everything your saying except if the failure rate of a cheap battery is 0.01% who is going to buy 10,000 cells to test till they find the dud?
That’s a valid point, however: what failure mode and scenario are we worried about here? I’m concerned about explosions and fires. Failures of that type come during charging. The charging-explosion cannot happen if the charger terminates properly. As far as I know, the explosion won’t happen during low-current charging either . So your in-flashlight charger may ruin cells by overcharging at low current, but it won’t cause them to blow up. “Failures” that don’t involve vent-with-flame are really not a big safety concern in my book. If the cell stops working properly (terrible voltage sag, low energy storage) that’s not a safety concern.
i got a flashlight for review that seems to charge at 5V and 1A with no control circuitry, i wonder what would happen to a cell left on that for a while