Headway battery pack FIRE! <lot pics>

[Jason27]

Jim, How about some compensation from headway? Send choot a new pack.

 

[circuit]

Jim, How about some compensation from headway? Send choot a new pack.

Did Headway assemble the whole pack? If not, it's not their fault and is up to the OP's conscience to blackmail Headway or not. My guess is they will give away a new pack. Not because its their fault, but just to hold user's anger low to keep this fire below mass public's level. Because the PEOPLE (as a group) are stupid and will never go to deeper understanding what went wrong - bottom line "HEADWAYS BURNED". Its always the end manufacturer who gets harmed. Just like sellers on ebay - no warranty or protection from any customer screwing with you.

Anyway I am amazed how many possible reasons of the fire we have thought of just by looking at these photos... The lesson is that there are too many failure possibilities in most battery packs and proper security measures are essential.

 

[chroot]

No I never ask anything from headway for some compensation.

Jim, How about some compensation from headway? Send choot a new pack.

Sent from my Amazon Kindle Fire using Endless Sphere

 

[Jeremy Harris]

Ouch ! A battery pack builders nightmare.

Are you recalling any packs ?

Why? I can't see any real evidence that the manufacturer was at fault, can you? Seems most likely to have been an installation related problem, maybe vibration, chafing, arrangement of wires, so not likely to be the manufacturers fault.


JimmieD,

Thanks for the useful contribution, it's rare here to get an honest opinion from a manufacturer, and I'm sure this thread will help spread the word that any pack is potentially dangerous and none are 100% safe.

Huge bummer man, glad nobody was hurt. Thanks for sharing. Sorry to hear!

In the end IMHO, it's the BMS' fault. One was or another, the cells were abused, and the BMS aught to not allow it to happen, with multiple tiers of protection, or else why even bother.

No evidence in those photos that the BMS was at fault, if anything the BMS still looks fairly intact, and the seat of the fire seems to be in the wiring, not the BMS. As the pack wasn't being charged or discharged at the time the BMS wouldn't have been doing anything, anyway.

The power loss from even 16 fuses is going to create a fair bit of heat, and add to the heat load right where you don't want it. Even 20 to 30 watts of extra heat inside a pack that's well protected is going to heat it up, and lose power.

I suppose all this boils down to "resistance is fusile"?

(sorry, it's not a perfect joke, but I'll not likley get as good a chance to use it any time soon)

Nice one AW! The Douglas Adam's fans will get it, for sure!

Jim, How about some compensation from headway? Send choot a new pack.

Why? In what way are Headway at fault here? All the evidence suggests that fault was installation related, rather than a manufacturing defect. Some bright folk have looked at this in detail for a day or so, and none of them have come up with a problem that could be put down to Headway, so what do you know that we don't that suddenly makes it a Headway problem?

I detest this blame culture we have, where people automatically seek compensation for any accident. Don't get me started on lawyers that encourage it, either...............

 

[etriker]

Had I built that pack I would recall it.

I would want it back to look at and study.

Trying to figure out what happened with pictures would be a nightmare. I would want to know.

I had been talked into doing this.

http://www.wheelchairdriver.com/BM-MK3-lithium-battery-powerchair.htm

Not now.

 

[Ykick]

Hobby King RC lipo wiring is fuses.

Like majority of your posts, wrong. Turnigy RC Lipo relies on PCB traces to act as fuses and it works.

@chroot - sorry to hear about the loss of your pack but glad no one was injured.

We deal with a lot of potential energy here folks. Whatever your chemistry of choice nothing is 100% safe or immune from flames so best plan and park/store accordingly.

 

[etriker]

Hobby King RC lipo wiring is fuses.

Like majority of your posts, wrong. Turnigy RC Lipo relies on PCB traces to act as fuses and it works.

@chroot - sorry to hear about the loss of your pack but glad no one was injured.

We deal with a lot of potential energy here folks. Whatever your chemistry of choice nothing is 100% safe or immune from flames so best plan and park/store accordingly.

Did not know that. Thanks for clearing that up for me.

Sorry for all the confusing and misinformed newbee like posts. I will try and not post so much. The only reason I jumped back into the ES mess was so I can pm people that have stuff for sale. Will shut up now.

 

[Jeremy Harris]

Hobby King RC lipo wiring is fuses.

Like majority of your posts, wrong. Turnigy RC Lipo relies on PCB traces to act as fuses and it works.

@chroot - sorry to hear about the loss of your pack but glad no one was injured.

We deal with a lot of potential energy here folks. Whatever your chemistry of choice nothing is 100% safe or immune from flames so best plan and park/store accordingly.

Did not know that. Thanks for clearing that up for me.

Sorry for all the confusing and misinformed newbee like posts. I will try and not post so much. The only reason I jumped back into the ES mess was so I can pm people that have stuff for sale. Will shut up now.

Nothing at all wrong with posting, as long as any uncertainty in advice given is clear. We do have a lot of people who read this forum and then go and do as they've read, so it's important for their safety, and to help them build safe and reliable ebikes, that advice given is correct, or if in doubt, couched in language that makes any uncertainty clear.

Unfortunately a lot of folk will read a post written in definitive terms as if it's gospel, and the result could then be nasty or expensive (or both) if the definitive sounding advice turns out to be wrong. If you know something to be true, preferably by experience, then posting about it is great, as it expands the knowledge pool. The only thing a few of us will pick up on from time to time is definitive sounding statements that we know to be incorrect, purely to try and head off others having problems from following it.

 

[999zip999]

This a good read with a lot of answers. We will not get answers without questions good or bad. Thanks All

 

[317537]

Hey, once the ooze gets out and gets enough air I think here is ant issue. Maybe put the cans into sleeves that can contain some venting without allowing the ooze to get out all over the hot parts and get to enough air, it like throwing oil over a real hot fry pan. In the worst case scenario if you can avoid the ooze getting all over the hot cans it may increase safety.

 

[circuit]

After pointing out the charge wire... The wire shorted out, no fuse on it... The pack is too weak (headways are quite crap, my testing shows) to burn it away as a fuse, so it heats up badly... The plastic tray melts right off, many wires and cells short together... And here you have it.
Also it looks like most or all of the burning is not from cells, but from that crappy plastic array. And this one is on headways, as they did it from wrong plastic.

 

[JimmieD]

Had I built that pack I would recall it.

I would want it back to look at and study.

Trying to figure out what happened with pictures would be a nightmare. I would want to know.

Although this would be ideal, UN3840 regulations and IATA regulations does not allow shipping of damaged batteries. There is much involved with shipping Li-ion cells and batteries.....if they are shipped properly and according to international shipping regulations.

After pointing out the charge wire... The wire shorted out, no fuse on it... The pack is too weak (headways are quite crap, my testing shows) to burn it away as a fuse, so it heats up badly... The plastic tray melts right off, many wires and cells short together... And here you have it.
Also it looks like most or all of the burning is not from cells, but from that crappy plastic array. And this one is on headways, as they did it from wrong plastic.

I may have misunderstood your post, but I completely disagree with you that it is on Headway, and that 'they did it from wrong plastic'. I am not here to create a debate or argument, but my name is on that battery build as well as many others out there and I will not stand by to be told that I did it from the 'wrong plastic', whatever that means. If referring to the plastic cell holders as the 'wrong plastic' what would be the correct plastic? And is the 'correct plastic' cost feasible for not only manufacturing but also distribution to consumers? And would consumers be willing to pay for it or would they have 'sticker shock'? Please enlighten me so that I can look into it.

You say the charging wire first shorted out, that is the first culprit, now the real question should be (IMHO) HOW did it short, rather than jumping to no fuse, Headway cells are weak and would not burn a fuse away anyways, thus causing the plastic to melt, which in turn melted everything else and shorted it....did I understand this correctly? It is easy to be an armchair quarterback, and from your post it is apparent to me that you have a distaste for Headway cells and have let your views dictate the outcome of your synopsis.

Just working through all the various scenarios to see if it leads to something else or creates a dead end, and to help with educating those who are reading this including me! :wink:

 

[circuit]

After pointing out the charge wire... The wire shorted out, no fuse on it... The pack is too weak (headways are quite crap, my testing shows) to burn it away as a fuse, so it heats up badly... The plastic tray melts right off, many wires and cells short together... And here you have it.
Also it looks like most or all of the burning is not from cells, but from that crappy plastic array. And this one is on headways, as they did it from wrong plastic.

I may have misunderstood your post, but I completely disagree with you that it is on Headway, and that 'they did it from wrong plastic'. I am not here to create a debate or argument, but my name is on that battery build as well as many others out there and I will not stand by to be told that I did it from the 'wrong plastic', whatever that means. If referring to the plastic cell holders as the 'wrong plastic' what would be the correct plastic? And is the 'correct plastic' cost feasible for not only manufacturing but also distribution to consumers? And would consumers be willing to pay for it or would they have 'sticker shock'? Please enlighten me so that I can look into it.

You say the charging wire first shorted out, that is the first culprit, now the real question should be (IMHO) HOW did it short, rather than jumping to no fuse, Headway cells are weak and would not burn a fuse away anyways, thus causing the plastic to melt, which in turn melted everything else and shorted it....did I understand this correctly? It is easy to be an armchair quarterback, and from your post it is apparent to me that you have a distaste for Headway cells and have let your views dictate the outcome of your synopsis.

Just working through all the various scenarios to see if it leads to something else or creates a dead end, and to help with educating those who are reading this including me! :wink:

Whoa whoa, dude, calm down.
I don't know who has assembled the pack and I really don't care. If you say its you - OK with me and, most likely, with everyone else.
Yes, I do have some intimate insight in headway cells. One thing I know for sure: they have very high internal resistance. This means, if they are shorted, highly possible that they will heat up instead of burning down the wire/connection/etc. I have tested many cells from few years of manufacturing span, even the "newest one", which I got in person directly from headway family.

About the plastic. You didn't do anything wrong here (I hope). You simply used what headway sells - that orange plastic tray. From pictures I guess that these are manufactured from cheap plastic. Not just because it melted real quick, but it even did quite a good job at sustaining the fire. Parts like this must be made from high temperature, fire-retardant plastic. Not the best example, but PA6 would have done a better job. So this part is headway's fault.

About the fuse... There isn't any on charging line. And that's your fault. I guess that a low power charger was used, so 10 Amp fuse would have been enough to hold the current and to blow if there is a short.

--
Anyway the exact cause of the fire is unknown. But this is a good lesson to everyone... You can't get too safe with batteries.

 

[deVries]

About the fuse... There isn't any on charging line. And that's your fault. I guess that a low power charger was used, so 10 Amp fuse would have been enough to hold the current and to blow if there is a short.

Is this a safety feature that only works when charging? If so, then this did not prevent this fire. Battery had been charged & bike was ridden a few miles & parked when this happened.

Otherwise, your point is a good one to have fuse when charging. I think diode would work too? Yes No? Or, use both fuse & diode for some reason(s). Comments?

Thanks.

 

[chroot]

Let's calm down. I just wanted education everyone to learn about my battery fire incident.

Jim is very excellent professional built the battery pack. You need to remember that this is not Jim responsible for the incident.

I asked Jim (JimmieD) check this thread out and it's a good example of the education.

 

[Alan B]

I think it is important to learn what we can from each incident, and in this case we have some great pictures and information to look at. We should not be looking to place "blame" there are too many factors that we will never know.

In thinking about what we have seen and read here, I take away a couple of considerations:

1) We need to insure that wiring is not chafed, pinched, or damaged.

2) Any wiring that, when shorted could cause significant heating should be fused or current limited very near the power source. Codes generally call for fusing to protect wiring against fire. There may not be any particular code applicable here, but we can learn from what happened or might have happened here and see the value in that code recommendation.

3) We need to insure that the battery pack itself cannot move and cause chafing, or otherwise cause shorts.

Based on this I plan to go back and review my wiring harnesses. I had always planned to put fuses on charging lines but have not done so yet in some cases. It is time to consider fixing that. While we can always say that we won't have chafing/shorting of the wiring harness in reality it cannot be perfectly implemented. There is always some unusual event or the effects of long term wear that can cause a short. It is important that these shorts don't lead to a disaster, so some form of current limiting needs to be provided near any high current source.

Thanks for a good discussion,

 

[dnmun]

the fire was not caused by the plastic insulating standoff bushings. the nylon topeak bag was the combustible, it burned off the seat and melted the plastic coatings on the headwaycells. it led to the ignition of the plastic standoffs later because of the heat generated by the combustion of the bag.

we do not know that the charging wire was the ignition source imo. it may have shorted out when the heat from the bag melted the insulation but i thought that was the high temp insulation on that 'silicone' wire.

rather than addding a buncha fuses, why not just remove the positive lead from the battery from the BMS. the fuse would be in the B+lead immediately off the pack, and the charging lead can attach on the other side of the fuse. the battery wire could just run directly to the controller and the charging lead can be taken off beyond the fuse. but just remove all the high voltage sources from the BMS space, rather than more fuses, but you can use more fuses, if you wanna.

make the BMS a circuit breaker in the negative battery lead and get it away from the positive leads.

 

[cal3thousand]

It's amazing to me that chroot is one of the calmest in regards to his posting demeanor. He's the one that had the fire.

Chroot,

sorry this happened to you. I'm glad your kids found it and quickly alarmed you. (they deserve at least a week of late bedtimes and double desserts )

Thanks for the share. Makes me think twice about where my LiPos are sitting and the mechanical condition of the pack they are in.



Gets me thinking.... Is there some kind of material or package that we can devise for our homemade packs that would burst in a fire spreading flame retardants in an attempt to reduce potential disaster from snowballing? Maybe someone should sell something like this on ES. :wink:

 

[cal3thousand]

Would it be beneficial to have a fireman look at the damage and give some forensic feedback? Take to the local firehouse...

 

[cal3thousand]

Would treating parts of the pack in this stuff help at all?


http://www.ebay.com/itm/New-FLAME-RETARDANT-SPRAY-ON-FIRE-PROTECTION-/370481627162?pt=BI_Security_Fire_Protection&hash=item56426d001a#ht_3251wt_953

 

[Lessss]

The fireD would love to look at it too, but don't be surprised if 1 1/2 later some bureacrat passes some addition fire code restrictions on ebike batteries that make them astronimical in cost and pretty much illegal to own.

 

[Jason27]

I agree. I can see the government getting involved with more regulations especially with shipping.

 

[Alan B]

These cells, at least the ones I have, are very tight into the plastic blocks and require force or tapping with a mallet to seat them fully. If there are restraints to insure the plastic blocks can't vibrate off the cells then they are restrained pretty well, at least for a small pack like this. If you had one several feet long then more external support would be required.

The key thing is that every high current path that presents a short-circuit risk needs to be current limited in some fashion. Wires leading away from the pack can always be subject to some situation that causes shorting. The current delivered to external wiring needs to be limited, this is basic electrical fire safety. We don't know exactly what happened here, but it might have been prevented by a fuse in the charging lead, if that was the first thing to short. The fact that the main fuse was blown open indicates that circuit was shorted late in the event, after the fire was already started, or that the main fuse somehow failed to blow fast enough to prevent a fire.

If a low impedance short is not interrupted the batteries can become so hot as to melt the plastic supports and form new shorts locally inside the pack. This is not the cause of the problem, it is an effect. Improving the support system is nice but not the first priority.

 

[teklektik]

chroot-
Just got a belated ping from ES about this thread - really sorry to see your Mundo get torched.

These cells, at least the ones I have, are very tight into the plastic blocks and require force or tapping with a mallet to seat them fully. If there are restraints to insure the plastic blocks can't vibrate off the cells then they are restrained pretty well, at least for a small pack like this. If you had one several feet long then more external support would be required.

If a low impedance short is not interrupted the batteries can become so hot as to melt the plastic supports and form new shorts locally inside the pack. This is not the cause of the problem, it is an effect. Improving the support system is nice but not the first priority.

This seems a good summary of the situation. My experiences with the Headway mounting system, etc are similar, although I might add that the Headway end blocks are effective components but not a complete mounting system in their own right. I would recommend a plywood or other hard/rigid base to bear the weight evenly and prevent localized stress points due to uneven or soft (e.g. foam) support that might cause the somewhat brittle Headway end spacers to fracture. While intact the mounting system is rigid and offers good spacing/insulation between cells.

Judging by the appearance of the fuse itself that is likely a MaxiFuse.
The MaxiFuse is also the only one available in a high enough voltage rating for this application.

I agree, plus the maxi is quite a good fuse in terms of minimal resistive loss - just 1.2 mohms for the 50 A rated one. Add in that they are readily available pretty much all around the planet and they seem to be a good choice.

The fact that the main fuse was blown open indicates that circuit was shorted late in the event, after the fire was already started, or that the main fuse somehow failed to blow fast enough to prevent a fire.

I used a couple of these in the same holders as used by chroot to protect my two Headway 8s2p packs and just removed them yesterday. Although the fuses themselves are attractive for the reasons stated, the fuse/holder assembly is not so good.

I had a weird charging problem yesterday using per/cell chargers and found that the 50A Maxifuses had melted into/with the holders - one fuse leg in each of the two holders. The metal in the fuse legs had actually become brittle and one had enough resistance to prematurely terminate charging. The holder terminal connectors are essentially push-on Faston connectors and over time apparently developed enough resistance to heat severely. Incidents of shorted controller FETs which blew a breaker but never the Maxis may also have damaged the Fastons.

As AlanB points out, the Maxis were not the cause of the problem, but after two concurrent Maxi failures in conventional holders, I could not with conviction say that chroot's Maxi/holder offered adequate protection to prevent matters from cascading. I am personally looking for an alternative for pack protection in the general vein of the ANL design...

 

[liveforphysics]

Would treating parts of the pack in this stuff help at all?


http://www.ebay.com/itm/New-FLAME-RETARDANT-SPRAY-ON-FIRE-PROTECTION-/370481627162?pt=BI_Security_Fire_Protection&hash=item56426d001a#ht_3251wt_953

No.