If you want a good Lipo fire you need a good cell , failed cell also fail at burning.
the first step is to overcharge the cell to about 5V to start decomposing the electrolite to methane and other stuff like that , overcharging also allows lithium to build metallic dendrides that react a lot with atmosferic oxigen and moisture.
While overcharging the cell you shuld also keep an high current ( above 1C) to keep the cell hot , if the temperature is too low you will have just only smoke bu no fire.
The easiest way to have a Lipo fire is to connect the positive lead of a single Lipo cell to the positive of a well charged 12V Lead Battery , and when you are ready just close the circuit and the lead will start overfeeding the Lipo .. at the end you may have your fire
another way to have fire is to make the cell running in the cell reversal condition , but also here you need a good cell to start with ; in this case you start with a discharged (2V) cell and just reverse the polarity of the above and have the Car Lead battery driving the cell to 0 and starting a reverse polarity charging , be carefull that in this case current will be very high and you may have also burning wires and not only burning cells
so.... Give me a reality check here then. These astoundingly dangerous lipo packs that everybody warns everybody about seem like they need a fairly specific set of parameters to go all critical after all.
Simply puncturing a pack (any pack) didn't work. So, the pack needs a good charge, if not a full charge to go when punctured? Even then, would a pack with a normal charge - my charger won't charge them at over 4.2V - still, maybe not blow at any given time? (I was under the impression that all you needed was a tiny puncture in a pack and it would go up in flames...)
I'd guess that, at zero charge, the thing is almost inert. Is that correct? The one thing I didn't do is pour water on it, I'm thinking that wouldn't go well.
So. Let's say your bike is sitting in the garage charging up, and the pack is disconnected from everything else. As long as your charger doesn't malfunction, it can't go up? You're charging at a slow rate, and it shuts off well before something like 5V.
If you short-circuit a fully charged pack sitting in your bike, it - might - go up in flames... but that's what you have fuses in the circuit for, right?
Let's say you're fully charged and riding hard, and go down. The packs have been discharging at a high rate, maybe they're warm? They scrape along the road and maybe puncture... is there a good chance they'll go up then? It sounds like that may be one of the most likely situation for a catastrophic incident, honestly.
It seems like the common wisdom is that these things are a bomb waiting to go off... I honestly thought the things would start going up at the first shot. When I hit it with the torch, the second time, and got nothing but burning plastic, I was pretty surprised. As I said... I just need a reality check. At the moment, the Danger Lipo Danger sentiment seems to be a bit of hysteria.
for sure Lipo CAN be dangerous and different Lipo cell may behave differently , but to start a reaction you need a minimum activation energy , if a cell is dead .. is dead ... if a cell still containing energy may release it in the wrong way.
A lipo can be dangerous if you use it outside a well know range of current and voltage ... lipo is not intinsically safe .. an intrinsically safe cell is safe always , even outide working paramenter .. Lipo IS NOT INTRINSICALLY SAFE ... it works .. is ok when is inside is working paramenters .. but if you move outise the bondaries a fire wil start. So you are not sitting on an armed bomb ... you are just sitting on an unarmed bomb and sometimes someone or somethin will try to pull the trigger ( crash , failed Bms , failed Charger, internal defect , vibration , internal shorts ) Lipo is ok for racing , for experimenting and to be stored in a fireproof workshop and bike .. is not safe for everyday riding
BTW in your case there is another variable , with a nail you puncture the cell and the nail keeps the cell short , you was using something that was drilling a hole in the cell and leave a nice , clear EMPTY hole without short circuit.
at 0:46 of your video , if the cell was a little more charged and there was a nail ore something like that to keep the short you will have your fire.
The smoke stopped because the internal component just burned and stopped the short ( acting like a fuse) also there was too little energy to start.
OK, so you need a conductor piercing the cells? I've still got a few cells that will hold a charge for a bit, I'll give it a try. Wait, I just watched that video. There's a nail in the side, it looks like, and then it gets hit twice with another nail that is removed. That's not "one puncture and FIRE" from where I sit... sorry.
As far as being unsafe for everyday riding... I know a few people who'd disagree with that, what with the fact they've been doing just that for close to a year now.
Originally Posted by Athlon
A lipo can be dangerous if you use it outside a well know range of current and voltage ... lipo is not intinsically safe .. an intrinsically safe cell is safe always , even outide working paramenter .. Lipo IS NOT INTRINSICALLY SAFE ... it works .. is ok when is inside is working paramenters .. but if you move outise the bondaries a fire wil start. So you are not sitting on an armed bomb ... you are just sitting on an unarmed bomb and sometimes someone or somethin will try to pull the trigger ( crash , failed Bms , failed Charger, internal defect , vibration , internal shorts )
Yeah... thanks for the comments, but this does seem like more vague hysteria than actual information to me. Crash? Yes, maybe. Failed BMS and charger? OK, a remote possiblity. Internal defect, vibration, internal shorts? Sounds pretty vague and unlikely, can you be more specific or cite examples?
I'll buy that they can "puff" and fail, but suddenly burst into flames under "normal" use just because of vibration?
...and just to put this into perspective, by this measure I'd say that a tank of gasoline is intrinsically UNsafe. By the same yardstick that I've been running on a gas bike for 40 years, I'm thinking maybe lipo is not that bad?
Just to narrow down the spec the real dangerous chemistry is the Cobalt based one , the Cobalt oxide is unstable at higher temperature and release oxygen , the oxygen act as oxidizer and start the fire.