Lipo Fire on Chick Bike

[Grinhill]

brilliant story, Green!

[liveforphysics]

The flames billowing out of that burning bike with flowers on it is just too perfect. I love it. I can't stop re-watching it.

[EBJ]

You should have thrown the lawyers card in the lipo fire while it was still burning.
I agree that lipo-fires in public are bad for us all. If mine ever light up I'll do my best to put it out before anyone sees it.

Was that pack just sitting in that bike basket unprotected? Did you ever check the cell-voltages to ensure the BMS was actually working? (is that even possible with this battery ? )

If I handed a girl a bike and it caught on fire, I'd expect her to kick my ass, i'd say you got off real easy.
I did like the bit about "we will remember this forever" hahaaa.

[Joseph C.]

Very lucky, it could have been much worse. Plus, someone could have decided to throw water on it to quench the fire.

Water doesn't do Jack squat to lithium batteries. There is no metalic lithium in them.

My mistake.

[Ykick]

So, what's the likely cause? Low cell reversed?

[Arlo1]

Yeh I wonder what caused it. The is so very few good BMS's on the market if any.

[Green Machine]

My best guess its the turn signals amberwolf talked me into installing on the front of that bike short cirquited and caused a catastrophic fire.

You guys are playing with fire with this turn signal thing.

SO the bike was built with a metal plate at the bottom of the basket for the battery to strap to. Originally the battery was strapped in really tight and we only used one battery on the bike. But after a while we started switching batteries out on it, and each battery is a slightly different in size depending on whether it has corking protection around it or not.

So seriously my best guess of what happened is planning on taking the road route through the GG park i didnt take as much care strapping the battery down as I normally would.

The path through the frisbee park was a spontaneous detour. I dont think it is a coincidence that the bike burst in flames in the roughest part of the ride. The bike obv has no front suspension and the jarring up front must have been pretty severe.

I believe the battery jiggled loose from its strap and then hit one of the sharp edges of the metal plate.

I noticed when the fire intitially broke out that the battery was loose from its strap. I am not sure if the battery had bounced loose or burned loose however.

Justin had visited my house and we had taken an ebike ride a few days earlier and he had checked out the the battery packs. He commented that they should have a hard metal case of some kind to be safe.

He also said that from importing hundreds of many different kinds of chinese lipo he had no success on any pack and had just about given up. His comment was that until panasonic or sanyo or some company like that decided to construct a pack with bms, lipo packs would continue to be unreliable and unsafe and nearly impossible to sale to the general public.

Oh also...when a pack is constructed with BMS its very inconvenient to unwrap the pack from its shrink wrapping and check each individual cell. Everyone i know who rides with these packs basically just charges and rides with them and forgets about them. The BMS will usually shut down the battery when any abnormality occurs. I have thousands of miles on these packs and this is the first fire mishap. Of course i am taking much larger risk of fire since i ride about 10x as much as the average ES member i believe.

Also liveforphysics had warned me in an earlier post that he had tested these battery space cells and they are the most dangerous cobalt chemistry he has ever tested. Now I see what he is talking about.

I think a better quality cell may have just fizzled a bunch of smoke which wouldnt have been nearly as fun.

[AussieJester]

I think i speak for many here when i say this GreenMachine, frock the battery, wheres the pics of the 23 year old Asian chickie babe

KiM

[Gordo]

I like the wicker basket touch. You might as well wrap the lipo in gasoline soaked rags and tie a bundle of cedar kindling around them.

[GCinDC]

that is hot!

hot.jpg (40.17 KiB) Viewed 784 times

[Green Machine]

You guys are going to get me into trouble getting me to post pics and babbling etc.

That is my hot wifes beloved daisy bike this girl just fired up. I am kind of in a jam here.

Sick brag post again..my wife is smoking hot.

I am into women way out of my league...i would recommend that to all you guys.

But wife and i are recently separated so i am not doing anything that immoral strolling through park with another woman on wife bike. Just killing time really and starting fires.

[AussieJester]

Sorry to hear about the separation buddy, your obviously doing it tough to... in all seriousness though GM, not many know about the interwebs, I wouldn't worry too much about what pics you post..
KiM

[vanilla ice]

Charge bag around the pack + a steel wire basket would have been much more boring.. What all is in that smoke btw? I've inhaled a little before also.

[Green Machine]

You know it was really cool witnessing my first lipo fire.

Now i know why physics is so into it.

The wicker basket didnt make any difference at all. The basket was burned away within a minute or so.

The fire burned for about 8-10 minutes steady not letting off, and not exploding either. It was just a nice solid fire. Like a controlled burn that lasted forever.

I should have started putting sand on it immediatley but i have let so many of these moments pass that this time i did the right thing and instead brought out the camera.

After a few minutes of filming the fire was in full effect. My first thought was we would just sit there and let it burn itself out since the fire was safely elevated on the bike away from starting a golden gate park forest fire.

But then i noticed that because the wicker basket had a metal floor the bike itself was not damaged at all, and with the wicker basket burned away it was easy to just knock the battery away from the bike onto the ground to salvage the bike frame. The only damage to the bike is a little burn marks on the front fender. Imagine the front tire didnt even pop (we rode away).

So only after that realization of bike preservation did i knock the battery to the ground.

And Only then did the frisbee golfers get proactive on putting out the fire afraid somehow that the nearby trees were going to ignite. It turns out a frisbee makes a pretty good shovel. For 8-10 minutes maybe 12 people were just standing around the bike like saying stuff like wow...unbelievable....how traumatic....is it going to explode? how the hell did that happen? An ebike eh? I forgot to mention frisbee golfers are mostly stoners and they were pretty cool about things.

It was a really nice intense but controlled fire.

Shit happens...

[grindz145]

Badass...

Did you shoot them with a gun or something?

[dogman]

Not suprised that mechanical damage to the cells is one possibility of the cause. I keep preaching, put something protective around those batteries. The first lipo fire I ever heard of was caused by a metal battery box having a sharp edge. It cut the cell on an early lifepo4 pack and set a converted vespa on fire. The pack itself was not well secured, and had nothing to protect it but duct tape.


But it could easily have been the battery murdering system let the cells get undercharged. Same thing seems to have been the reason my original ping died. Instead of cutting off, it let the battery discharge to below 1v per cell. (3v) If the bms let it get too low, then it could flame in use later.

Freaking cool though, that you got it on video.

[999zip999]

I'm with Aussie-Jester let's see some pic's of the chick.

[EBJ]

I agree it should have at least been covered in a charge-bag.
It sure would have smoked, but ppl are quite used to seeing smoke come out of cars (actually just steam from radiators, but a lot dont know the difference)
So from a "public safety" standpoint I imagine seeing smoke wouldn't be as bad as seeing flames.

[liveforphysics]

Not all LiPo is sensitive to physical abuse. BMSBattery just happens to make some of the most dangerous LiPo cells I've ever tested. They are as dangerous as original Generation 1 RC LiPo from early 2000.


Here is a modern 20Ah LiPo cell charged to 4.15v, but that got the outer bulk of the tab ripped off from some rough handling, so we decided to do strike it until it would ignite. We were all disappointed. Even an A123 cell smokes and sometimes flames up if you pound it like this. NMC LiPo just lays there and does nothing no matter what you to do it. It also handles >10v overcharge and just sits there taking it.

But sadly, you guy's cant get your hands on these unless you're buying in the 10's of millions of dollars per order, and have an approved pack design by the company that passes all the exhausting safety requirements.

[Arlo1]

But sadly, you guy's cant get your hands on these unless you're buying in the 10's of millions of dollars per order, and have an approved pack design by the company that passes all the

why the hell is that? Or is this just a temp thing?

[scotticeberg]

I want some of those dow/kokam lithium nmc cells. Now, not later.


http://www.dowkokam.com/presskit/english/Dow_Kokam_Customer_Reference.pdf

[fechter]

Daaamn, I'm glad that didn't happen when I was riding your KMX. The batteries are right under your butt on that thing.

The packaging on those Lipo batteries does not look very robust and not really suitable for 'normal' use without some kind of protective housing. I agree that a metal box, even a fairly thin one, would be a great safety enhancement for those.

After the initial "vent with flame" hydrogen gas ignition, they appear to burn much like a container of gasoline. I think if it was inside a can, the amount of flame would be greatly reduced if not eliminated. Somebody posted a video of a Lipo going off inside a steel 'cash box', much like a small tool box. That really seemed to reduce the damage potential outside the box. Any box or container would need a vent of some kind, but I don't think it needs to be terribly large. A flame arrestor screen over the vent might work to prevent any flaming.

In addition to a metal or non-combustible box, some kind of padding to prevent the wires or cells from shorting after an impact would seem like a good idea. I'm trying to think of materials that are durable, non-combustible, withstand high temperatures and also non-conductive. Metal is great except cell connections can short out against it.

[liveforphysics]

After the initial "vent with flame" hydrogen gas ignition, they appear to burn much like a container of gasoline.

The part that burns so well afterwards is the plastic polymer separator.

[mvly]

humm... putting Lipo on the front basket without shox is probably not a good idea. Lipo are unstable when exposed to heavy shock and probably all the pot holes and bumps were compromising the Lipo battery pack. That's just my Opinion. But then again it might be the BMS or both or neither. Too bad the Lipo probably destroyed all the evidence. : )

[liveforphysics]

Lipo are unstable when exposed to heavy shock

I love guys who can watch a video of LiPo enduring an absurd amount of shock, beating, smashing, pulverizing into ripped shreds of cell between asphault and a 24" wrench, not do as much as get warm or make a puff of smoke, and then make a blanket statement like "LiPo are unstable when exposed to heavy shock."

There are all different types of LiPo. BMS battery has the most dangerous cells I have ever tested from anywhere. Other types of LiPo can be stabbed and crushed and shot and pounded and grinded against a grinder shooting sparks, overcharged, over discharged, shorted, and not do as much as make a puff of smoke or even get warm.

It's like playing with gunpowder, having it burn, and then declaring powders are dangerous, when some are as dull as beach sand, though they my outwardly look identical.