Lipo failure

[Jonathan in Hiram]

Repeated connecting/disconnecting combined with "connectors were a little bit dicey".

Please change the threat title. We should never combine lipo with the other word, because is is counterproductive for the cause since the public has an inaccurate impression of the overall risk with lithium batteries. Instead let's borrow a quote from Elon Musk regarding the explosion when trying to land a SpaceX rocket, and always refer to these events as "rapid unscheduled disassembly" of a lipo battery pack.

In fact, with the forum software that deals with cursing, can't the forum do that automatically for every instance of "lipo fire" or "battery fire"?

Ah, bulshytt...

http://www.urbandictionary.com/define.php?term=Bulshytt

Bulshytt
Technical and clinical term denoting speech (typically but not necessarily commercial or political) that employs euphemism, convenient vagueness, numbing repetition, and other such rhetorical subterfuges to create the impression that something has been said. The word, not to be confused with the broader term, "bullshit," was coined by author Neal Stephenson in his speculative-fiction novel Anathem.

According to Stephenson, people who use this type of rhetoric are "more prone than anyone else to taking offense (or pretending to) when their bulshytt is pointed out to them." Ironically, people who use this seemingly confrontational term can be "excluded from polite discourse, unless they say the same thing in a different way, which means becoming a purveyor of bulshytt oneself. The latter quality probably explains the uncanny stability and resiliency of bulshytt."
Source: Anathem (appendix: glossary) Neal Stephenson, 2008.

The best corporate blogs shed their bulshytt and speak to people in the same tone and manner as if reader and blogger were chatting over a keg of beer. There’s a reason for that. People are exposed to plenty of corporate happy-talk and marketing prose in your ads. They don’t need more.

 

[ecycler]

Repeated connecting/disconnecting combined with "connectors were a little bit dicey".

Please change the threat title. We should never combine lipo with the other word, because is is counterproductive for the cause since the public has an inaccurate impression of the overall risk with lithium batteries. Instead let's borrow a quote from Elon Musk regarding the explosion when trying to land a SpaceX rocket, and always refer to these events as "rapid unscheduled disassembly" of a lipo battery pack.

In fact, with the forum software that deals with cursing, can't the forum do that automatically for every instance of "lipo fire" or "battery fire"?

big fan of that idea if people will stop recommending them to newbs like in this thread:
http://endless-sphere.com/forums/viewtopic.php?f=3&t=65776&p=991290

 

[dnmun]

A picture as requested,

this is as good as it gets for any analysis of this failure. just a lotta yakking and i saw no evidence he actually looked closely enuff to find where it shorted and take a picture of the short.

this is the second fire with a balancing charger. the electronics will not allow it to overcharge so it had to be a short of some type imo. with regular balancing no pouch could have been so far outa balance to overcharge even if the sense wire provided false voltage reading back to the balance network so it could overcharge.

 

[neptronix]

And you know better than all of us combined because....? :lol:

 

[amberwolf]

My #9 battery is a strange story in itself actually. Right now its only reading 2 cells, both 4.12 and 4.11 so I guess with my battery conditioning going on now I will try to plug it in, but my volt meter only reads 2 cells too so.

Then either some of the cells have failed down to a voltage below what your charger/meter can read, or more likley the balance wires have broken somewhere between the cells and the connector. If the pack itself reads normal voltage as if all the cells were the same voltage, it is probably the latter. If it only reads two cells' worth, then it's probably the former.

Either way, you should fix that issue before using it any further, because if you don't, you can't know the actual state of the individual cells, and can't predict what will happen.

 

[ddk]

My #9 battery is a strange story in itself actually. Right now its only reading 2 cells, both 4.12 and 4.11 so I guess with my battery conditioning going on now I will try to plug it in, but my volt meter only reads 2 cells too so.

Then either some of the cells have failed down to a voltage below what your charger/meter can read, or more likley the balance wires have broken somewhere between the cells and the connector. If the pack itself reads normal voltage as if all the cells were the same voltage, it is probably the latter. If it only reads two cells' worth, then it's probably the former.

Either way, you should fix that issue before using it any further, because if you don't, you can't know the actual state of the individual cells, and can't predict what will happen.

I'll add I had a single LiCo 20C cell failure (Zippy-branded RC pack) creating a complete short, and taking it's paralleled buddies with it. It was under use at the time
one moment everything's happy
the next moment the bike lost some speed and I saw that I "lost" 4.something volts one of my metered battery packs..
I immediately stopped and checked the battery.
Very undramatic I might add, as the pack in question didn't even rise above ambient temperature.

But the end result was the 5S battery packs were now acting as 4s battery packs.
Since rebuilt into a number of 3S packs for lights and such.

Bottom line:
some LiCo cells can have a failure mode that can produce a dead short
-without fire-
...

 

[dnmun]

it really is too bad there was no close up of the spot where it shorted as i said. just the picture he took from about 4' away of the entire pack piled up in the yard. if we coulda seen inside where the short started it might have helped some people.

of course some people will never accept that shorts are the real risk because it removes the validity of their multi page expositions.

 

[Syonyk]

Shorts are a risk. The behavior of the rest of the cells in the face of a dead short then determines how bad things get.

 

[Hillhater]

Personally, I don't trust the basic concept of reconfiguring a pack for charging, or needing to plug into balance boards for balancing.
The risk of incorrect or poor contacts is always there no matter how carefully it is done and the damage may not be apparent at the time, only manifesting itself at some later time.

 

[neptronix]

Easily fixed with labeling and color coding.
This is something that only a meticulous lipo user will do though after blowing some stuff up :lol:

The same principle applies for any battery. It's just that the bar for building a RC lipo battery is super low and a lot of people just jump into it without understanding these fundamentals. Myself included, when i started using lipos as a total friggin' newb.

Personally, I don't trust the basic concept of reconfiguring a pack for charging, or needing to plug into balance boards for balancing.
The risk of incorrect or poor contacts is always there no matter how carefully it is done and the damage may not be apparent at the time, only manifesting itself at some later time.

 

[cal3thousand]

Personally, I don't trust the basic concept of reconfiguring a pack for charging, or needing to plug into balance boards for balancing.
The risk of incorrect or poor contacts is always there no matter how carefully it is done and the damage may not be apparent at the time, only manifesting itself at some later time.

Personally, I 'reconfigure' packs for charging, but with risk mitigation measures. It is all handled by the keying of Anderson PP45s. The discharge plug serializes the necessary bits and a separate charging harness parallels them. Anderson's are designed for repeated connections. I would not be comfortable doing the same with bullets and JST plugs (which are not well designed for repeated re/connections)

 

[ddk]

Personally, I don't trust the basic concept of reconfiguring a pack for charging, or needing to plug into balance boards for balancing.
The risk of incorrect or poor contacts is always there no matter how carefully it is done and the damage may not be apparent at the time, only manifesting itself at some later time.

Personally, I 'reconfigure' packs for charging, but with risk mitigation measures. It is all handled by the keying of Anderson PP45s. The discharge plug serializes the necessary bits and a separate charging harness parallels them. Anderson's are designed for repeated connections. I would not be comfortable doing the same with bullets and JST plugs (which are not well designed for repeated re/connections)

Wut they just said-

-except I do use the JST connectors for checking pack status and the *very rare* occasions the packs need balancing. The battery packs are paralleled at the cell level via their respective JST connectors and the group is terminated in a JST... color-coded 'natch. (Sharpies that expensive- I think not)
Most packs are rapidly approaching 3 years of age, the oldest pack 4 years; and the JST connections are fine.
I stopped counting the number of cycles last year, after they surpassed 1K.

NO-body should approach this stuff of DIY battery packs without a **better plan** of action, including never having to 'br-reak down' a battery pack for a normal charging cycle.
That really is asking for a fire/explosion to happen with ANY rechargeable battery chemistry.
-as in OOPS, I ACCIDENTLIED MY ...*POOF*

-but that's just my personal opinion

 

[dnmun]

i have 100A of 72V SLA in parallel with 87Ah of 24S lifepo4 ping pouches and 36Ah of 21S HK lipoly and nanotech tied together in parallel. i plug in the two chargers that push 18A of current and let it charge to 88V and balance itself.

i never ever worry about overcharging or over discharging or pulling some JST plug which in this case would be about 120 plugs.

i have two of the D131 on my lifepo4 pack and one of the D131 on my lipo and it does all the work for me and the chargers make the juice almost for free since i got both the chargers dead for free.

i have no problem balancing the lipo. 36Ah wide and it can be kept balanced with just the one BMS.

 

[cfrgsn1]

Hey so did some further investigation of the failed pack, in an attempt to look for a short/fault. However, this thing burned nice and hot, burnt through most of the balance leads entirely, and the thing is more of a burned out lump than something recognizable. It's very hard to tell what could have been a short originally, and what shorted when it caught fire and melted all the wires etc, as well as me using the hose on it. by the looks It was one pack that failed to begin with, which when it caught fire burnt a few of the cells of the other packs. It's still sitting in the corner of my lawn if anybody would like to take it for further investigation, I have only poked it with a stick a few times to separate the packs and try and see whether it would catch fire again

 

[markz]

Fire, yes! More like fireworks!

Oh man, I had the scare of my life just now.

Im in my office in the basement of a very nice house. Im on the computer, next to me the charger is charging.
All my batteries were low, so I was trying to get them all up to 3.5V, and I did, except the last batch. They were a pain to get back up.
Charging at 6.5A four batteries in parallel. They were at 14.4V.

I hear pop, I say huh, I hear another pop, I hear some rushing gas sound, not much, I smell something too, I look I see ones puffed and broken the Turnigy 4S hardcase 5Ah....I clue in this aint good.

Im thinking, Im thinking, what do I do, what do I do.....thinking some more, I go with 6 pack of batteries taped together to the main level balcony patio table, why not I say to myself, nothing bad will happen. Not a minute later the fireworks start to happen, sparks and flames are going out the sides as I hear a rush of gas probably. For like a minute or 2. Not only one went, but the plastic caught fire. I say to self this aint good, put out fire or the others will blow up too. Well a few minutes later as the fire is out, another lights up and does its fireworks show. Now I scramble for the fire extinguisher, but I blow on it instead and it goes out. I put everything on baking sheet, I go to street and lay it down. Now my hearts a pounding. Still is, after the fire truck came and used its huge fire extinguisher.

Damn these RC Lipo batteries, damn them!

I admit its 100% Operator total NEWBIE error, charging at 6.5A four in parallel in a 6 battery packed all taped together. Hardcase batteries. Charging from the very bottom, probably 3V maybe less. Its been 30 minutes now, my hearts still pounding. Man now im chucking the rest, throwing them away, I need peace of mind....

Buh Bye RC Lipo! Buh Bye! I got no need for you anymore RC Lipo. See ya later. Good Riddance!

Now I need to find the safest batteries there are. No more games with silly little RC chargers. No more games!

Im looking at Allcell from ebikes.ca, allcell website, sffbike all expensive. Not my fortay.
Im googling, SAFEST battery, I get some NMC, NCA, Panasonic NCR 18650PF they say is fool proof (I Like), LifePo4 is all game too, AA portable Power Corp
http://www.batteryspace.com/lifepo4cellspacks.aspx Im total game, they sell packs. I will find out what charger is best, and buy suitable voltage.

I vow from now on to let everyone know about the risks associated with RC Lipo, by which the likes of Hobby King slings. Heck I am going to put it into my signature line at the bottom header of my posts. BBQ is a very good idea if you are willing to risk it. And one thing I personally learned, since mine were 5Ah, and I was charging at 6.5A or was it 6A, cant remember, that when your charging from dead bottom ~3V, to 3.5 or storage 3.85, at 1C+ you got to be very careful. Im no expert but thats an issue. I should have, if I was thinking or smart, to have charged at 0.5C. I was getting cocky, I really was, running my batteries low and charging at 1.25C.

 

[amberwolf]

Now I need to find the safest batteries there are.

If you ignore problems with them that you *know* exist, and just use and charge them without fixing them, there *is* no "safest battery".

Assuming one of the packs that failed was the one you referenced in my quote of you here, where I recommended you fix the problem before doing anything else:
http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=70611&p=1066880#p1065936



I don't know that it would have made a difference, but I expect that it would have, if you'd done something about the problem you had first.

I will find out what charger is best, and buy suitable voltage.

Try the Cycle Satiator from Grin Tech. It's not cheap but it's Niiiice.

You can set it up for anything you like, up to it's maximum voltage and current and total wattage, and create multiple charging profiles for different packs and types. It's also mountable to your bike without worrying about vibration shaking it apart inside (unlike most of the typical ebike chargers), and weather resistant (also unlike most of the typical ebike chargers).

I vow from now on to let everyone know about the risks associated with RC Lipo, by which the likes of Hobby King slings.

Make sure you also let them know that the risk could be lessened by fixing problems you already know exist before you do anything with them, (and checking for such problems in the first place).

I was getting cocky, I really was, running my batteries low and charging at 1.25C.

I have a feeling it had less to do with the charge rate than the problem you'd previously reported (and presumably did nothing about, since you never replied or mentioned fixing it).

 

[TheBeastie]

I go with 6 pack of batteries taped together to the main level balcony patio table, . Not a minute later the fireworks start to happen, sparks and flames are going out the sides as I hear a rush of gas probably. I put everything on baking sheet, I go to street and lay it down. Now my hearts a pounding. Still is, after the fire truck came and used its huge fire extinguisher.
.

What about some pictures?

 

[neptronix]

That sucks.

Whenever i have batteries that are low... of any type at all ( including car batteries ), i always charge them at a super low rate to start, never a high rate. This is where their internal resistance is highest. If a cell is far below 3.0v and you charge it at 1C or higher, you will either take life off the cell or cause some serious heat that could lead to a thermal runway.

Not to insult anyone here, but i feel like i should stay quiet about RC Lipos and their benefits in the near future. There are a lot of guidelines to follow and a lot of room for error and your average person can't deal with it. I had some newbie mistakes myself, but they were small ones. A lot of people seem to have big ones that end up with a big bang. 95% of the time, the problem is user error. But there has been that 5% where a sketchy pack spontaneously ignited and i don't like to hear that..

 

[Gregory]

Charging at 6.5A four batteries in parallel. They were at 14.4V.

.....

since mine were 5Ah, and I was charging at 6.5A or was it 6A, cant remember, that when your charging from dead bottom ~3V, to 3.5 or storage 3.85, at 1C+ you got to be very careful. Im no expert but thats an issue. I should have, if I was thinking or smart, to have charged at 0.5C. I was getting cocky, I really was, running my batteries low and charging at 1.25C.

Sounds like at 4 x 5Ah batteries in parallel (20Ah) and you were charging at 6.5A, then you were actually charging at a leisurely 0.325C.
I doubt that was the cause of your problem.

Still I'm glad your place is OK and hopefully you can learn from it. LiPo is not something I think should be recommended for beginners.

 

[dnmun]

you should not waste time putting an overheating pack on a cookie tray.

to cool off you battery pack when it overheats it is much more effective to flood it with water under the tap in the sink or dunk it into a bucket of water to cool it off and stop the thermal runaway before it can heat up more of the pack and provoke it into thermal runaway.

 

[Alan B]

Sorry to hear about the problems with your batteries. Probably best to move on to a plug and play commercial product.

A pack is damaged when it is overdischarged. The choice then is to discard it or attempt to recover it. Recovery is a high risk project.

Charging overdischarged lithium batteries is risky. Whether it is in a pouch, cylinder or rectangular configuration, either commercial or homemade. It should either not be attempted, or done with full knowledge that it is risky, and precautions taken. Very low current should be used, much less than usual. Expect that it might fail into venting and don't be surprised. Charge in a location where that will not be a problem. Be fully prepared for it.

Reconfiguring packs is high risk. Doing it frequently is asking for a failure. Most connectors are not designed for high connect/disconnect cycling. Design your system to NOT require frequent reconfiguration for any reason.

Drawing 65A from a 5AH pack is asking for trouble. Do not exceed 25% of the manufacturer's continuous ratings. If packs get warm during discharge then reduce current or increase parallelism or cooling.

Drawing high current heats up the connections and softens insulation, and may melt internal soldered connections. Poor wiring or mechanical support quickly leads to shorts. Shorts are an instant road to massive failure for any battery type. Avoid stress on wires and the resulting shorts. Protect with appropriate fuses or circuit breakers.

Take precautions with your batteries. Think of them as solid gasoline. Treat them with respect and care.

 

[Ykick]

@markz - what’s your charging setup? How were you monitoring and protecting individual cells while charging or discharging for that matter? Let’s venture a guess, nothing?

You “think” they were below 3V but you really don’t know? SOB - some people can’t sharpen a Pencil. It’s not the Pencil’s fault…

 

[Syonyk]

http://www.batteryspace.com/lifepo4cellspacks.aspx Im total game, they sell packs. I will find out what charger is best, and buy suitable voltage.

I'm very happy with my Batteryspace LiFePO4 pack and charger - I've got this one: http://www.batteryspace.com/lifepo426650battery384v132ah506wh40aratewithpcmfore-bike.aspx

It's been quite happily powering my commute and charging without any drama whatsoever for the past year and a half with zero fiddling involved. I think I switched the main connectors over to Anderson PowerPole at some point, and that's about it.

Not to insult anyone here, but i feel like i should stay quiet about RC Lipos and their benefits in the near future. There are a lot of guidelines to follow and a lot of room for error and your average person can't deal with it. I had some newbie mistakes myself, but they were small ones. A lot of people seem to have big ones that end up with a big bang. 95% of the time, the problem is user error. But there has been that 5% where a sketchy pack spontaneously ignited and i don't like to hear that..

I'd be happy with that. Lipo packs have their place, and I argue strongly that the vast majority of ebikes are simply not the place for them.

They are too demanding for something intended to be ridden and charged regularly, and the packs are a significantly greater collection of cells than the normal RC hobby use, where a single pack (6S or whatever) is the normal size.

I know it pains many people on this board to spend any more money than the absolute bare minimum, but a commercially built and tested battery pack with BMS really is a good option for a lot of people, and they don't tend to fail catastrophically. You can save a lot of money with lipo cells, but even with good care, they go off and light bikes or houses on fire. That's not an acceptable tradeoff, in my opinion.

 

[Alan B]

I'm sitting here looking at the battery pack of a modern thin laptop. It is built with lipo cells. Same as the smartphones and many other commercial products that you have and charge every day in your house, car and bedroom. Reports of fires with these cells were fairly common a few years ago, but now they are not. The quality of the cells, systems and management has increased, and fires are rare these days. The safe chargers refuse to charge a system that does not meet safe charging parameters, and the management system's discharge control prevents overdischarging in normal circumstances.

The issue is how the cell system is put together and managed. Many 18650's are cylindrical versions of the same chemistry used in mylar bags.

The key is how these cells are packaged and managed. Some chemistries are safer than others, but even the "safe" cells are quite dangerous when shorted, overdischarged, overcharged or physically abused. Some cells burn hotter than others, but they all burn hot enough to ignite surrounding material and burn your house down. Any of them can do that. Small electronics failures cause fires quite regularly. The requirement to use only "nationally recognized testing lab" (such as UL listing) rated equipment is to keep your house and workplace safe. I suspect if you check you'll find quite a few things in your areas that are not rated, may not be safe, and should not be used. You may already have the device in your house or office that is going to burn it down. Many electronics items come without the appropriate ratings and lacking the safe design requirements to pass them. The risk is not only from lithium batteries.

At least some of the companies that make cells refuse to sell them to anyone unless they prove first they have the technological know-how and experience to build safe packs from them. They know that a poorly built pack from their high quality safe cells can burn down a building or take down an airplane, and they intend to stay out of the news by regulating who can use their product and control the quality and applications of the end system.

That's the bottom line. Only people who have the knowledge and experience to build safe packs should do so, from ANY cell type. If lipo scares you a bit, that's good. But don't assume a different cell solves all the issues. Have the same respect for other chemistries as well.

Lipo is the scapegoat here, getting the blame, when more inexperienced people weld together 18650's we will see more fires from them too. The ease of experimenting with Lipo tends to attract less experienced and less careful builders. The amount of technology needed to make Tesla's 18650 packs effective and safe is staggering. Welding a few cells together doesn't get you to a safe system.

So if you have any doubt about your ability to make and manage a mechanically and electrically reliable pack from any cell types, then do us all a favor and don't do it. If you do decide to build packs (from any cell types) then take full responsibility for making safe packs and managing them safely.

 

[Syonyk]

Modern smartphones and tablets use a single pouch cell, 3.7v nominal, 4.2v (ish) fully charged, of the desired capacity.

It cannot be abused like you abuse a series pack, because there is no ability to have balance issues, drive a cell below cutoff voltage, etc - it's always balanced, and the control electronics simply do not let you abuse it. If it's drained too far, it won't charge again - and due to the low voltage cutoff being well above the safe bottom voltage for the chemistry, it's almost never dragged down deep enough to cause any damage to the battery.

Battery welding is sufficiently more demanding than stringing together lipo pouches to discourage people from doing it as frequently.

And as far as cell quality goes, yes, if you use UltraFire 18650s, you're going to have a bad time, but high quality 18650s are easily obtained. I'm under the impression that Hobby King Lipo packs are pretty much discards from other use, at best. Their "bad cell on arrival" rate certainly would indicate they're discards.