On Hold: Venting Li-Ion in a Light

Hey BLF,

I’ve finally mustered up courage (and time and place) to make a 18650 cell vent inside a flashlight.

I couldn’t do this at school because I’m sure not everyone is as comfortable as I am messing around with li-ion cells. Now that I’m back home with access to the rooftop, hopefully I’ll be able to trigger a thermal runaway and see what happens to the Warsun CT9T.

Here’s what I have for now:

The light itself.

An iCharger. I think about 7-8A will suffice, but we’ll see.

A lead-acid battery to power the charger.

An acrylic cover to shield the cameras from the blast. It’s too thin to stop the flying flashlight fragments (as they’re known to even shatter glass), but to slow them down and even be used to show damage and destruction.

I’ll get the experiment going tomorrow and will let you guys know how it goes. I’ll post a video too if my camera survives.

In the name of science... Well done. Looking forward for test.

Big thanks for doing this Ryansoh3. :beer:
Did you pick a battery?

You could build a inexpensive shield that would stop a bullet.
Water. Build an acrylic box to hold a volume of water. Camera sits behind the box and films through it. I’d just go for 10-15cm of water for this. Place your camera in a plastic bag since it may be splashed.

Go for it! Great experiment. And pay as much attention to placing the camera and the lighting as possible (high speed???)

looking forward to the result!!!!!

Darn, can’t you use a worse flashlight

Isn’t that a decent host?

Why can’t he use some cheap crappy $5 light?

I will gladly donate a direct charge port UF-535

Like these crazy sadistic guys that buy brand new iPhone 6’s and then take a grinder to em or stick em in a blender just to watch people squirm :_(


Be careful!!!

I’m curious to know the battery being sacrificed too. A cheapie may well vent at that rate but a quality one with low internal resistance may well survive.

Lexan/polycarbonate would make a better shield, but if that’s all you’ve got…

Looking forward to the results. :slight_smile:

Thanks for your replies guys. :slight_smile:

I’ll be using an old cell that I was able to source for my scooter battery. I couldn’t make out the brand, but it seems like a 2200-2600mAh cell but is at least 4 years old. I think it’s pretty tired. :open_mouth:

I’m using the Warsun because it’s a good host. It represents the decent quality lights that we use and seems pretty air-tight with the double o-rings. Not sure how using a cheaper light would affect the experiment, but I’d like to find out too.

As for the shielding, I think I’ll have some water bottles forming a parameter around the flashlight to absorb the shrapnel. Thanks Halo for the suggestion.

I’ll be using a Sony NEX-5 to record the main video and also my phone to record 60fps high-speed footage. It can also do 120fps, but the quality gets really bad. Edit: Playing around with the camera settings, I don’t think 120fps @ 720p is that bad. I think I’ll stick to that.

I´m going to grab some popcorn! 8)

Are you going to charge at 6-7A?

A better more realistic test would be 1A. That would duplicate what could happen if a 1A charger failed to terminate. Trouble with that rate is though it could take a very long time for something to happen. At any rate, I think the sudden release of energy would be from an internal short that suddenly developes.
This will be good!

One way to get a 1A constant source would be to charge the cell in series with a 100W incandescent bulb powered at 110VAC thru a full wave bridge diode array.

Definitely looking forward to seeing the results!

I have to see this one. Great idea. If you are successful I predict this thread will blow up!

You might as well use a good battery with that good host BLF style.

I have a feeling that the gases will just vent out of the side switch.

Good idea & thanks for doing this :slight_smile:

I agree with DanielM, because we always strongly recommend & many of us like to do hot builds (:arrow: me :smiley: ) i think we would learn more by using a good high discharge battery or any of the often recommended panasonic ones.

I’ll send you a brand new panasonic 3400, that host is too good to wreck with a old no name cell, it needs a decent send off…!

Hmm that’s a good point. I can charge at 1A with my iCharger, so the setup isn’t a problem. However, I have a feeling that the cell might not vent at all or at least will take a very long time. Maybe I can take a 18650 and see if it vents first without a host and then see what happens if I put it in one.

I didn’t bring any spare 18650s with me for spring break, but if all goes well and I’m still in one piece, I can accept host and battery donations for summer break testing. That would be fun!

That might happen, it’s a possible outcome for this experiment. I picked this light because this has an integrated charging port, but I still haven’t figured how to trigger a thermal runaway inside a light without one. Maybe putting it inside an oven?