What kind of lipo fire do you want to see?

[ExperimentalRC]

I recently crashed my beaver and wasn't able to find it until a day later and by then the 3s 2200 was puffed and wouldn't even register on my lipo checker. I charged it back up but it isn't able to hold a charge and does weird things. Currently the voltage per cell are 0.23, 6.43, 6.37. Im actually surprised the pack hasn't exploded yet. It is sitting on my porch in a lipo bag under a small box made of bricks. Now that its getting cold I want the season to go out with a bang.

I'm wondering what kind of lipo fire you guys would like to see: over charge, over discharge, or a puncture. Im not entirely sure if there is a difference. Id also like to hear your stories about lipos, it can be positive or negative. Im gonna try a poll but I dont know how that works so it would be great if you could also leave a comment.

 

[joshuabardwell]

I have seen both over-charge and hammer/nail in other videos. I'd like to see you try to burn it up by over-discharging it. In other words, over-discharge so it's definitely damaged (already did this), then charge it using a standard program at 1C or something--nothing insane--and see how what it takes to actually burn up.

An example test protocol might be something like this:

- Discharge to some low value like 2 volts per cell at 1C (use your charger's discharge program for this).
- Charge at 1C. Try balance charging? Not sure. You have definitely got a toasted cell there, so balance charging may just be a waste of time. I dunno.
- Repeat these two steps maybe ten times or until you get bored, or until the battery lights up during charging.

Repeat, charging at higher C rates. If the battery continues to not blow up, discharge to lower values. I dunno. I'm just spit-balling here. This way, we get some useful data instead of just a video with a big fire in it.

 

[pgerts]

I have never seen a battery burn because of to low volt (energy content) - please show!
What you have is not what you think.
You probaly have one bad cell and 2 cells with 3.2 volts.

 

[jtbutcher]

I would like to see the over discharge too

 

[stay-fun]

If you have a hammer, doesn't every problem look like a nail?

I'd like to see it hit by a hammer, hard. See what happens

 

[ExperimentalRC]

Im not 100% sure that a lipo could over discharge and explode, but I'll try my hardest.

 

[joshuabardwell]

Im not 100% sure that a lipo could over discharge and explode, but I'll try my hardest.

It's not that it will explode from over-discharging. Obviously, in the discharged state, it doesn't have enough energy to explode. It's that over-discharging causes chemical changes in the cell that increase the internal resistance, which causes the cell to overheat and explode when it is subsequently charged.

The question I'd like to see answered is just how sensitive this situation is. Can I, for example, discharge a pack until one cell hits 2.8 volts, then charge it again at 1C without it blowing up? What about 3C? Does it matter the number of times I discharge it, or is it the depth of discharge that is important. Etc... Obviously we are not going to answer all of these questions with just one pack to experiment on.

 

[Christopher14]

I'm wondering what kind of lipo fire you guys would like to see: over charge, over discharge, or a puncture. Im not entirely sure if there is a difference. Id also like to hear your stories about lipos, it can be positive or negative. Im gonna try a poll but I dont know how that works so it would be great if you could also leave a comment.

I have a story for you.

A few months ago I crashed my FT Spitfire, and the 4s 1000mAh battery was dented. So in my usual fashion I decided to destroy it in a spectacular way, this time in stead of using a hammer and nail I opted for the less dangerous option: Using my .22 caliber rifle to puncture the battery. (with a hammer and nail you run the risk of partly incinerating your fingers) So heading out into the woods with the damaged battery and my rifle, I surprised a large bird of some sort that probably was wondering what a 15-year-old with a rifle was up to in his woods. After a few more minutes of walking I arrived at the spot I usually go shooting at, and hanging the battery by the wires from a stump of a tree I retreated to a safe distance. After loading my gun I took careful aim, and pulling the trigger I watched the battery smoke slightly and then stop. Being disappointed that the battery did not explode, I did a little more point and puncture work. After five or six more shots I went to inspect the damage. After walking the twenty-five yards to the battery I found several holes in it that where smoking a little. After this unspectacular result I think the next logical step is a larger caliber gun. I will report back when I use a bigger gun on a battery.

Hope you like the story!

 

[Rogueraven]

I guess given there is not a .50 Cal on the Puncture option it got to be overcharge

 

[Christopher14]

I guess given there is not a .50 Cal on the Puncture option it got to be overcharge

A .50 Cal would be great. You don't just happen to have a .50 Caliber sniper rifle in the garage ExperimentalRC?

 

[muidaq]

I've overdischarged a couple until they were dead. No fires from that. Gonna need something a bit more drastic.

 

[Christopher14]

Like a .50 Cal?

 

[Klinger RC]

SHOOT IT!!!!!

 

[Christopher14]

SHOOT IT!!!!!

Oh yes.

 

[Christopher14]

If you have a hammer, doesn't every problem look like a nail?

I'd like to see it hit by a hammer, hard. See what happens

I tried that. not very spectacular, just very little smoke.

 

[stay-fun]

Too bad!

I did manage to heat up a pack quite a bit at only 0.5C discharge below 3V/cell. Surely shorting the pack at close to 3V/cell would heat it up quite a bit…?

 

[Christopher14]

Although a garden hoe does have a nice effect on a 3s 1300.

 

[ExperimentalRC]

Haha no I don't have a .50 cal rifle. The closest thing to it would be my daisy pellet gun, but I'm thinking that won't do as much damage. Lol. I think I'll try the over discharge and recharge method later this after noon.

 

[Christopher14]

TNT?

 

[MVogan]

TNT?

These LiPo batteries have about 2/3 the energy density of TNT. So don't bother getting TNT. You won't need it.

I hate to be a killjoy here, but I don't recommend actually doing any destructive testing on these batteries. It is dangerous and also may be illegal.
I worked in batteries for 9yrs. Our local fire chief found a guy on youtube who would intentionally short batteries until they exploded. He called the fire chief in that youtube user's area and they went after him. I don't know what happened in the end, but this is serious stuff.
Have you ever tried to ship a large battery pack? The regulations are insane because these are so dangerous if abused. However, they are quite safe if used properly.

Respect your batteries!
MVogan