Lipo fire- no one hurt- my fault

[liveforphysics]

A battery needs no flaws to explode when a 3s is paralleled to a 4s. Both packs are doing exactly what they are supposed to do in that situation. The 4s pack is discharging lots of current as it's voltage is pulled down a bit, the 3s is charging at some extremely high rate as it's voltage is pulled up. Eventually they are going to exceed the 3s batteries ability to accept more charge, it's going to undergo some decomposition that is exothermic, it's going to ignite the solvents and separator materials in the battery and keep them fed with the off-gassed oxygen from the cobalt oxide thermal decomposition to ensure the flames stay in a strong rushing burn until readily combustible components are devoured and oxidized. This generally makes a "whoosh" sound while it's happening, and just lasts a few seconds, maybe up to 10seconds of intense heat/flames. Then it has a period of minutes where comparatively minor materials like the shrink-wrap and tape and sticker and sticker adhesive etc all burn and make a nasty smokey stinky mess.

We've got this process down pretty well now. In this case, it has nothing to do with getting a high quality or low quality product. It's simply what a high C-rate capable cell is going to do in an extreme overcharge situation (which is what occurs when you connect a 3s to a 4s). As an example, A123 pouches do the same thing in extreme overcharge, as do most all of the cells capable of high C-rates. The cells that can survive something like this without bursting into flames are the ones that have such high internal resistances that they make real high performance from a small battery pack impossible. If you can settle for lower performance or the need to carry a much physically larger heavier battery (because you have to have some many high-resistance cells to discharge the current you require for high performance levels).


I think the big lesson there is one we've seen learned many dozens of times with varying degrees of failure outcomes, check and double-check wiring connections before mating, and ideally key connectors to make it impossible to fumble together connections that result in flames.

 

[etriker]

Unless of course it is a high quality battery with a fuse or bms.

Think laptop cells will do this ?

 

[etriker]

To be clear.

I think a high quality ebike battery is a battery pack built with high quality cells and a design that tries to prevent things going wrong causing a fire.

Because humans make so many mistakes.

 

[liveforphysics]

Unless of course it is a high quality battery with a fuse or bms.

Think laptop cells will do this ?

I think most laptop cells would survive this incident. However, it's a mute point if laptop cells wouldn't deliver him the performance required to get him out of his car and onto an ebike.

 

[etriker]

Unless of course it is a high quality battery with a fuse or bms.

Think laptop cells will do this ?

I think most laptop cells would survive this incident. However, it's a mute point if laptop cells wouldn't deliver him the performance required to get him out of his car and onto an ebike.

You need to think out side the box and wrap your head around the idea that ebike batteries and motors can make a bike go fast and not burn up !

 

[etriker]

Then be one of the people that makes it so.

 

[dogman dan]

Of course they can, but not at HK lipo prices.

For the last freaking time, this one was not caused by the quality of lipo used. But for sure, operators need to be a LOT more careful when they do choose inexpensive RC lipo to power thier EV. If you choose this chemistry, at simiar c rates, you have to be very careful. I say that daily, over and over and over. That applies no matter where you bought it or who made it!!!

Fuses might not have protected in this situation. If you have a 40 amp controller, then the 3s pack could have been overcharged by the 4s pack at a rate of at least 40 amps. You'd have a 50 or 60 amp fuse on it, right? Most battery pack fuses are downstream of everything anyway, not between each cell group of a series string.

Bet that pack that burned had very little to protect it from physical damage in a crash, or just a bike falls over at the bike rack situation. ANOTHER NO NO if that is the case.

One thing you did absolutely correct. Your pack was easy to remove from the bike when flamed. That saved your bike. MUY BUENO!

 

[etriker]

Of course they can, but not at HK lipo prices.

For the last freaking time, this one was not caused by the quality of lipo used. But for sure, operators need to be a LOT more careful when they do choose inexpensive RC lipo to power thier EV. If you choose this chemistry, at simiar c rates, you have to be very careful. I say that daily, over and over and over. That applies no matter where you bought it or who made it!!!

Fuses might not have protected in this situation. If you have a 40 amp controller, then the 3s pack could have been overcharged by the 4s pack at a rate of at least 40 amps. You'd have a 50 or 60 amp fuse on it, right? Most battery pack fuses are downstream of everything anyway, not between each cell group of a series string.

Bet that pack that burned had very little to protect it from physical damage in a crash, or just a bike falls over at the bike rack situation. ANOTHER NO NO if that is the case.

One thing you did absolutely correct. Your pack was easy to remove from the bike when flamed. That saved your bike. MUY BUENO!

So how many bikes are out there just waiting to burn because you and others on here suggest using these batteries on evs ?

Do you people at all feel bad you suggested people use these things when they burn or do you just say oh well you should have done the lipo rules better ?

Ebikes are now the #1 ev that will catch fire because of batteries ?

I really do not think you have studied battery pack design very much.

There is much info online about li ion battery pack safety design.

 

[etriker]

I am a battery pack builder with many packs on the road.

I have not seen a battery pack built at the cell level by Dogman or LFP or amberwolf ?

Before you start telling me about fuse location and what happens when you parallel packs lets see your packs you built from cells Dogman.

I put the fuse right on the wire where it comes out of the pack.

 

[dnmun]

bullshit. they can tell you anything they want. you cannot come on here and bully people like you are from texas.

your stupidity is leaking out all over here. you should shut up before even more people cannot stand to see your postings.

unlike your demanding insults, most of us offer opinions that might help others also to put their pack together in such a way that when stuff like this happens it can be managed. i think she did better than you can so put that in your pipe and eat it.

 

[etriker]

bullshit. they can tell you anything they want. you cannot come on here and bully people like you are from texas.

your stupidity is leaking out all over here. you should shut up before even more people cannot stand to see your postings.

unlike your demanding insults, most of us offer opinions that might help others also to put their pack together in such a way that when stuff like this happens it can be managed. i think she did better than you can so put that in your pipe and eat it.

You know what ? I have not ever told people to use HK lipo on a street ebike.

I got that going for me.

Are you a battery pack designer and builder ?

Let's see the battery pack you designed and built from cells.

Where do you put the fuse ?

 

[t3sla]

bullshit. they can tell you anything they want. you cannot come on here and bully people like you are from texas.

your stupidity is leaking out all over here. you should shut up before even more people cannot stand to see your postings.

unlike your demanding insults, most of us offer opinions that might help others also to put their pack together in such a way that when stuff like this happens it can be managed. i think she did better than you can so put that in your pipe and eat it.

You know what ? I have not ever told people to use HK lipo on a street ebike.

I got that going for me.

Are you a battery pack designer and builder ?

Let's see the battery pack you designed and built from cells.

Where do you put the fuse ?

Have any of your packs used the following?

-Kapton tape
-Flame retardant fiberglass sheeting
-3M VHB tape
-Nito electric tape

1 Meter Drop test

 

[etriker]

Right ?

How about the trike flip over test at speed ? That was a tough one !

http://endless-sphere.com/forums/viewtopic.php?f=3&t=42818

Or the bike falling over when parked test ?

I am testing the heck out of my stuff !

No fires or even a failed pack yet !

I sure have set myself up if one does burn down !

 

[etriker]

Someone was hurt by the way.

I got a real bad headache right after I first read this thread.

All lipo ebike fire threads make me depressed.

They are not going to stop.

It really is too late and I am beating my head against the wall.

 

[Ricky_nz]

Someone was hurt by the way.

I got a real bad headache right after I first read this thread.

All lipo ebike fire threads make me depressed.

They are not going to stop.

It really is too late and I am beating my head against the wall.

As we have said before this incident was not caused by the use of RC Lipo! Proper pack design is a must no matter what cells you use be it lead, nicad, nimh, lipo, LiFeP04 or what ever.
Whenever people are home building packs they really need to think about issues that could crop up and and work to mitigate them in their design.
Some people do worry me if they are building packs and they barely understand what an amp is but that will not stop us sharing information of how to build a good pack.
If people don't follow recommended practices and get in over their head it is not the forums problem.
In this case the need to reduce connections that can be made incorrectly has come up multiple times on the forum so was a known issue to be aware of.
You are actually burying good information about how to avoid problems with your incessant ranting.

 

[richmpdx]

I would like to 2nd the thanks as expressed by MattyCiii and others for your sharing this event on ES. Of course, we seem to be the most likely to learn from our own mistakes. Occasionally we can learn or refresh our learning by hearing about something that happened to someone else. I think most of us know that batteries are inherently dangerous. Even small batteries can be dangerous, so the large packs that we use to operate bikes can really cause some damage. None the less, after we use them for awhile, that knowledge can slip into the background. Thanks for the refresher course.

Rich

 

[TMaster]

As we have said before this incident was not caused by the use of RC Lipo! Proper pack design is a must no matter what cells you use be it lead, nicad, nimh, lipo, LiFeP04 or what ever.

I agree. This was caused by human error; and the error had nothing to do with Lipo's. But the effect is what is in question here. The real question is: Would there have been fire or ignition or would have it been as bad with other type of cell chemistry? The only real way to put this at rest would be to re-create a similar test with other types of chemistry cells. Under a controlled enviroment setting up a 3S and 4S paralleled packs of close or the same C and Capacity, pulling about the same amps. Then we would know if we had to jump off the bike, stop drop and roll, kick batteries into the ditch or just check the cells and replace the bad ones. BikeFanatic might have not even posted this happened if there wasnt a fire, he might have just slapped himself for hooking the lower Ah pack to a greater one, and replaced the cells.

bullshit. they can tell you anything they want. you cannot come on here and bully people like you are from texas.

Get your stereotypes right, we are hippie yuppie redneck kickers.

 

[dogman dan]

If it makes you happy, I just talked a guy out of using lipo on his street commuter on another thread yesterday. He was going to seal it up behind hard to remove covers and not be able to properly inspect them periodicaly. I advocate a lot more vigilance when using lipo on a bike.

There are some here, that recomend it for everybody, every situation. I don't always agree. I can't recall ever calling HK lipo high quality. I always say buy extra so you can weed out the dangerous ones.

BTW, I've flipped my lipo powered bike many many times. No damage due to smart battery box design. The box now has some serious dings, but never hurt a battery. I also always tell people to stop taping naked HK packs to the frame and riding around. I tell them to protect them better when carried in bags as well.

I just simply am not the guy here who advocates careless, undereducated use of lico. I don't charge with homemade chargers or store them haphazardly.

 

[etriker]

Higher quality li ion batteries are out there but cost more than HK rc stuff.

The low cost is why people buy HK lipo for ebikes.

And most people that buy ebikes give up on them because of batteries ?

The ebikes end up on craigslist cheap, not working needing batteries and the charger is lost.

I am in it for the long run so I saved my money and bought some real good cells that will last a long time.

My battery stuff and testing is headed toward using 12v drop in li ion packs to replace the sla batteries in some of the ebikes that are dirt cheap on my local craigslist.

ebike battery fires go back a ways and are a real bummer.

http://www.cpsc.gov/cpscpub/prerel/prhtml02/02251.html

 

[t3sla]

You'd think by now if some large public issue where to happen it would have already, it's been years of DIY bikes.

From an overall picture it's electric cars that take the brunt of the battery fire heat (apologies for the pun)

You have to remember Europe/Japan have million of lithuim ebikes doing their thing, if anything ebike batteries are leading in the EV PR dep. Millions of people are now charing 300/400/500Wh lithium packs in their home without fire.

Sure some tard will cause a fire with his home-brew peso HK battery pack, but from an outsider viewpoint it's just some tinkering mad scientist.

Electric bikes don't get a bad rap because someone on here acts a fool, you can see what's coming to a spaghetti rat-nest bike.

Average joe isn't confusing that with commercial bikes, which is where the revolution gains momentum (It gains flight with competition racing)

 

[etriker]

It is in jets where they get a lot of press too.

http://www.11alive.com/news/article/271405/166/Battery-causes-fire-on-Boeing-jet-at-Boston-airport

 

[Xrain]

bullshit. they can tell you anything they want. you cannot come on here and bully people like you are from texas.

your stupidity is leaking out all over here. you should shut up before even more people cannot stand to see your postings.

unlike your demanding insults, most of us offer opinions that might help others also to put their pack together in such a way that when stuff like this happens it can be managed. i think she did better than you can so put that in your pipe and eat it.

You know what ? I have not ever told people to use HK lipo on a street ebike.

I got that going for me.

Are you a battery pack designer and builder ?

Let's see the battery pack you designed and built from cells.

Where do you put the fuse ?

I designed and built a 176V 45 Ah Pack using the cheap 20C turnigy hobbyking lipo. The mass of batteries weighed approximately 125lbs.

We had numerous problems as it was a prototype snowmobile built in a relatively short timeframe. While I did have several vivid nightmares about what 125lbs of lipo going up in flames during a University competition would look like, None of the main issues we encountered were related to the quality of the batteries. Most of the issues we had were from our own design oversights, and the discovery that electrolytic capacitors also can deflagrate under certain conditions. :wink:


The highest quality lipo cells would not have made any difference difference in this situation. Heck, even the several thousand dollar a cell space rated lipo I have dealt with, even with all of their endless QC and Enviro testing would have failed if connected in a similar manner.

I am not sure that a fuse would have helped in this case, if it took 25 minutes to overcharge the battery its likely the current experienced would not have been much larger than its normal operating parameters. I suppose about the only thing that could have prevented this would be to have installed a rectifier. However large ones tend to be rather expensive, and bring their own set of issues into the equation.

While I understand what you are saying with the idea the energy storage devices should not have a failure mode that would cause it to explode; I just don't think that this idea is all that practical. Every high density storage method that I can think of can fail catastrophically. Think of how many planes have been knocked out of the sky from gasoline or kerosine explosions. It's the nature of the beast, you are storing vast amounts of energy. When that stored energy happens to leave your method of storage quickly, it tends to be in the form of fire.

Just about all of the ebikes on these forums even most of the ones coming from many manufactures I would classify as experimental. So mishaps are to be expected, I imagine if the bikes had gasoline on them, and we were embarking on a similar road of development. I would bet that there would also be a long list of people who had lit their bikes/ dogs/ eyebrows on fire as well.

I would not recommend someone brand new to power electronics and battery systems use lipo in their first ebike, as it is rather unforgiving of many mistakes. But to rule them unsafe to use for anyone is simply ridiculous. If you take the proper precautions, and use some smart design choices in your battery pack, it can be as safe as any other chemistry.

One of the main things that people often overlook (myself included) is designing your pack in a way that prevents systematic errors. So that you have it designed in such a way that it is at least exceedingly difficult to operate it in such a way during general operation that would cause something damage. Though I don't blame anyone, as this idea is a good portion of what goes into making a full production product.

 

[etriker]

They have a place racing rc stuff or on a race bike at the racetrack.

No need for them on a street legal electric bicycle in Florida.

The cells can short in HK lipo. This is a really bad design flaw.

Add that in with HK's very poor quality control.

The only time I have seen a dead shorted li ion cell was in HK lipo.

Quality cells don't dead short when they fail ?

I took the HK pack apart and every cell had nano 5000 printed on it except the one that had shorted.

Where else can you buy a cell that will short like this but HK ?

The battery inside had very poor soldering and looked like it was built by someone with poor skills or was very tired.

Did you win the race with your HK lipo ?

 

[etriker]

I replaced a car with an electric bike. I do not own a car anymore and am saving $$$ not owning a car.

My electric bicycle is not a toy or something from the future fair.

It is my real transportation to my job and back. Can't be playing with cheap batteries on my ride.

 

[John in CR]

BikeFanatic,

Glad you're ok. In your OP you said "next thing I knew I was on the ground..." There wasn't an actual explosion of any kind that knocked you off the bike was there?