battery fire

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derekderek

10 mW
Joined
Apr 16, 2025
Messages
34
Location
SW Florida
i was just cooking and heard the clothes dryer start making popping sound. checked dryer, it was fine. then i hear the same popping from garage right next to dryer. open door. garage black with smoke and one ebike battery burning away. cells popping and flying across the room setting a chair and a few other things on fire. the bike was not being charged and had not been ridden in a day or two. i bought the battery that blew during covid, so it isn't THAT old. i never opened the case on that battery so i don't think it is my sh!tty work. it was 2nd batt on bike. i don't think it was even plugged into the controller. i have to check but my feet are a little burnt from putting out a garage fire in my bare feet. we nearly lost the house to this ebike. of course, the wife is always crying about possible battery fires with us having 5 bikes in garage. man it is gonna suck when i tell her she was right! tell ya what. no more ebike batteries in the house.
 
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ok, the xt 60 connector on end of wire is not my work. so i can't blame myself for causing this and the battery was not connected so this was a charged but not charging battery that was not connected to anything. this is not supposed to happen!
 

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Yep, I tell people this all the time, don’t buy or mess with ebikes if you don’t have a place to store them and always store them at least 6 feet away from anything valuable like a car or house. Batteries do just fine outdoors year round as long as they’re not fully charged or in direct sunlight.
 
Wow. Glad you;re OK. You're lucky that you were awake and there to put out the fire. Looks like a Hailong case. You carried it on the rear rack for a second battery?

Not supposed to happen unless maybe those were low quality cells. After a few years, I can imagine the chemistry going bad, maybe an internal short circuit causes thermal runaway. But what do I know. Nothing,
 
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derekderek said:
this is not supposed to happen
Click to expand...

I would like some more information, please.

Did you buy the battery new? Or was it used?
Do you know what brand of cells were used in the battery? Grin's information suggests that cells from the big, established foundries don't fail - so knowing the brand of cell would be very, very useful information.
Who assembled the battery? That might be "what brand battery is it"?

Thanks.
 
derekderek said:
this is not supposed to happen!
Click to expand...
Indeed. So it would be very interesting to understand what exactly did happen. I've seen at least one another similar case, where a motorbike was just left alone and caught on fire after a day of sitting idle. It's perhaps the worst case scenario as you might not be around to realistically do anything about it. At the same time, we use multiple levels of protection to prevent anything like that happening.
 
1 year and 2 weeks old. 1 year warranty.. and i put it out with the garden hose. didn't occur to me i coulda got zapped, but electricity needs salt or similar dissolved in the water to conduct electricity well. actually i rolled the bike outside while battery was on fire. then put out the chair, etc. then i hosed the bike down and it was on it's side with batt against the ground.
 
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derekderek said:
here is the battery i bought.
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The most confidence inspiring thing about this thread is that battery is one of the least confidence inspiring ones I've seen. If our fav vid about battery fires is to be trusted, you can bet it was full of mismatched cells with no protections made at the lowest possible cost in the plant with no standards whatsoever.

I'm truly, terribly sorry for what happened to your bike, but it seems that it's just yet another case that will become a statistic showing that cheap packs of unknown origin can't be trusted, and not more than that in terms of overall, properly built battery safety.
 
so i just read how to put out Li battery fire. they all say it is not possible. garden hose did the trick nicely. i could hear those cells popping like silenced pistol shots. but they were done blowing by the time i hit the bike battery with the hose. i guess the short ate up most of the available electricity before the stream of water hit the battery but the fire went out immediately. there are still 10 or so cells that did not blow. i am thinking old used metal toolbox of Fb to enclose the batteries. but we have 6 bikes and batteries at the present. time to reduce the inventory a bit...
 
Santa Cruz had a fire(s) with their Hecklers (AIR, but it could have been a different model), then recalled and replaced the batteries, but that's the first instance I've heard with a "major" manufacturer (unless you include Canyon in that designation since I think they had a problem too).
 
Definitely no sign of brand name cells being used in that listing. Brand name ones tend to have things like safety vents to vent the boiling solvent instead of going off like pistol shots.
 
That's exactly the kind of battery i would expect to randomly catch fire.
1) unusually cheap
2) no mention of the cells inside
3) a brand with no reputation

On this site, most of us actively warn people away from buying these kinds of batteries. They tend to have poor construction, and even poorer quality cells. These types of packs have a dramatically higher chance of random explosion than one with quality cells and careful construction.

Sorry you learned the hard way, but glad you survived!
 
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when i bought this battery i knew nothing but volts amp hours and price. i assume the same can be said of the batteries on new bikes that sell for the price of a battery?
 
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derekderek said:
i assume the same can be said of the batteries on new bikes that sell for the price of a battery?
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I'm not quite sure how to read this, but...

Grin's perspective after much experience is that cells from the major foundries (Sony, Samsung, Panasonic, some others - I don't have the current definitive list) are very, very unlikely to go into thermal runaway without some very serious, unlikely provocation outside of any sensible usage.

Used cells, mixed cells (size, age, history, etc.), cells from "cheap" foundries, are the source of fires. Shady sources, cut-rate prices, fly-by-night, used - all should sound alarm bells. Improper usage, improper charging.
  • Does the source list the cell manufacturer? Is it one of the large, established manufacturers which has a reputation to uphold and is a sitting duck for bad publicity and lawsuits?
  • Does the source guarantee to use new cells in writing?
  • Does the source say it uses matched cells?
  • Does the source mention the safety features built into the pack? This is a reason to pay more, so they should be crowing about this to convince you to pay more.
  • Is the source itself trustworthy? Do they have a reputation to uphold and are they a sitting duck for bad publicity and lawsuits?
That sort of thing can guide your choices. Some different battery chemistries are inherently more safe, but the reason we use the more risky chemistries is that the power density is so much higher - it's worth the risk, if you buy from the manufacturers who actually know what they are doing and don't cut corners and don't over stress the battery.

Cheap sources that don't have to answer for the damage don't care. They have your money, and good luck to you. Same as a used car with leaky petrol hoses.
 
I would still be interested into a detailed account of what failed. There is a video of Justin from ebikes.ca trying to forcibly burn/explode Samsung cells ... without any success. Your battery must have been built very poorly to end in such a way!
 
Samsung and other higher grade cells will vent if the pressures get too hot. Some 21700 cells have two vents. They also have a pressure activated circuit interrupts under the positive cap that break the connection to the outside world if some external source is putting in or taking out too much current.

If you pull the data sheets on these cells, you'll find that they must take a short circuit at full charge with no fire. They are also rated to be overcharged to 6+ volts w.o a fire. UL tests extrapolate this to a full battery. Makes us feel good, but what about a crappy cell that develops an internal short and starts heating up, I think that's one of Grin's complaints, that a crappy cell can still pass all the UL testing,
 
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