Grin’s perspective of Ebike fires

Well that was ummmm....interesting! This is certainly a sensible option for removable ebike batteries. Most of us here aren't using those though.

Cheers
Where there's a will, there's a way. I'm certain windows large enough to expulserate soon to be aflame ebikes through are available.
 
I've seen a lot of companies claiming they have some material that stops a battery fire.
..yet in these same places i have not seen a test proving that they actually achieve that.

Turns out it's pretty hard to stop the ~5000F of heat lithium batteries can produce during a fire. You probably need to venure into using materials only found on space ships, and i'm betting that's uneconomical.

New record set for world's most heat resistant material | Imperial News | Imperial College London.

Even if you charged your ebike batery/ebike/escooter on a slab of hafnium carbonitride with a nafnium carbonitride box cover, radiant heat will set nearby objects on fire, and smoke is still going to make a toxic mess of your lungs and home. By the time there's ignitable smoke, it's too late. Monitor temperature and EXPULSERATE! Safely expulserate from your home before the damned thing bursts into flames. I only need about 20 seconds advance warning, before I expulserate the battery via the window.
 
Last edited:
The thermal materials I've seen used to pot or separate cells in battery packs aren't designed to resist fire, but to prevent it by absorbing heat from a potential runaway. They either serve as a heat sink or as a phase change material or both.

Potting turns battery packs into single use garbage. If the added mass of potting material were replaced with extra cells, then they probably wouldn't get hot anyway unless the pack is egregiously undersized for its job. You'd benefit in range, performance, and/or longevity from the added mass and expense, and you'd be able to service the battery when it eventually develops a problem.

That's one reason why I bought a large 19.2Ah/691Wh battery - I reckoned even if the advertised LG MH1 cells were fake, such a large battery composed of cheap Chinese counterfeit/rewraps would be capable of supplying enough continuous current for my needs. Despite being bought on Amazon, turns out I do appear to have genuine LG MH1 cells, considering it's performance. I should still have useful range when it's capacity is reduced with a couple of year's use.

Rather than repair, seems the likes of Bosch prefer to throw entire ebike batteries away - wasteful and poisonous, but perhaps safer? Repair does seem quite a tricky process, replacing duff cells with cells with matching characterstics (minus the duffness) etc. I can guarantee any battery I attempted to repair would burst instantly into flames.
 
Last edited:

The failure of blade fuses mentioned in the video is concerning, so I've taken to putting three in series to increase the probablility of one not failing.
 
Last edited:
Even if you charged your ebike batery/ebike/escooter on a slab of hafnium carbonitride with a nafnium carbonitride box cover, radiant heat will set nearby objects on fire, and smoke is still going to make a toxic mess of your lungs and home. By the time there's ignitable smoke, it's too late. Monitor temperature and EXPULSERATE! Safely expulserate from your home before the damned thing bursts into flames. I only need about 20 seconds advance warning, before I expulserate the battery via the window.

Good point. I think we might be at the end of the road of 'adding safety' to current lithium batteries.. the best way to get inceased safety going forward would be to change to another cell type like sodium ion or solid state which can be built so that they only smoke or die internally at worst.

Will hold off on my dream for ta 3kwhr ebike pack until then :)
 
I forget who it was ( JonesCG? ), but someone mentioned using a VOC ( volatile organic compounds ) sensor to detect a battery failure early. Typically batteries smoke some 5-10 seconds before they flame.. this basically gives an early warning to throw the battery out the window or run.. 😅

Nice, but i think we can do better!
 
Good point. I think we might be at the end of the road of 'adding safety' to current lithium batteries.. the best way to get inceased safety going forward would be to change to another cell type like sodium ion or solid state which can be built so that they only smoke or die internally at worst.

Will hold off on my dream for ta 3kwhr ebike pack until then :)

I want one of those - at my usual zero-effort 16Wh/mile, that'd last 187.5 miles and weigh about 18kg. My 36V 18A "250W" BBS01B mid drive converted 2006 Dahon Helios folding bike doesn't care about weight, but my wallet winces at the very idea. Of course if your 3kWh is built badly, that'll be a bloody big fire. :eek:

Long exposure photograph illuminated by moonlight on top of a very steep hill overlooking the city, while I enjoyed a kebab and coke. I've tidied the cables, added lights, Oxford lollipops and lasers etc. since. The pannier rack will be fine with a 18kg battery, it's withstood much more weight than that. Pannier racked battery, because I need my bike to fold.


bike-long-exposure-onplus-5-30-seconds-moonlight-s.jpg

tree-lights-24.7 (2).jpg

handlebar-oxford.jpg



I'm rather hoping lithium-ion is replaced with sodium-ion, before deep sea miners kill everything in the oceans:


 
Last edited:
Will hold off on my dream for ta 3kwhr ebike pack until then

Don't be that way @neptronix . Your disaster may be the spark conflagration that leads our societies rushing to that new low-burn future. You could be the first, or last rather!

It could be glorious...
 
Good point. I think we might be at the end of the road of 'adding safety' to current lithium batteries.. the best way to get inceased safety going forward would be to change to another cell type like sodium ion or solid state which can be built so that they only smoke or die internally at worst.

Will hold off on my dream for ta 3kwhr ebike pack until then :)

BEVs seem to average about 25 times that much pack, and they burn down a whole lot less often than petroleum stinkers. I think the risks are manageable, and mostly we just need to unplug our collective heads from our collective cloacas and stop using flashlight cells and knitting needles to do serious work.

Use the right tool for the job and you'll be much less likely to cut/smash/burn yourself.

That said, any tech that yields a badass battery without cobalt, nickel, lithium? Better than gold.
 
I forget who it was ( JonesCG? ), but someone mentioned using a VOC ( volatile organic compounds ) sensor to detect a battery failure early. Typically batteries smoke some 5-10 seconds before they flame.. this basically gives an early warning to throw the battery out the window or run.. 😅

Nice, but i think we can do better!
Good info! That'll be 5-10 seconds after my overheated battery has been expulserated via the window.
 
I want one of those - at my usual zero-effort 16Wh/mile, that'd last 187.5 miles and weigh about 18kg. My bike doesn't care about weight, but my wallet winces at the very idea. Of course if your 3kWh is built badly, that'll be a bloody big fire. :eek:

Yeah, my big problem is my area is really spread out, super mountainous, and i'm often forced into the car lane ( bike lane constantly disappears and appears with no warning ) and have to do 35-40mph for a bit to get back into the bike lane to do 25-30mph.

So yeah, my bike chugs battery and it's not a luxury item to have 3kwhr, i have 1.1kwhr and it's not enough for serious journeys.


That's a cool bike, dude. If you're ever thinking about swapping out the motor i'd consider switching to a hub motor because you can get a ton of torque out of a small hub with those 20" wheels ^_^

I'm rather hoping lithium-ion is replaced with sodium-ion, before the likes of Gerard Barron kill everything in the oceans:


Dude, this is a serious problem. We need to cut the world's energy use for transportation purposes massively. Going this route should be a non-option.
 
BEVs seem to average about 25 times that much pack, and they burn down a whole lot less often than petroleum stinkers. I think the risks are manageable, and mostly we just need to unplug our collective heads from our collective cloacas and stop using flashlight cells and knitting needles to do serious work.

A lot of ebikes live in apartments and up until now there were no standards on how commercial batteries should be built. Yah, it's a clown show. I think ebikes are on their way to becoming mainstream transportation and agree that we can AND should do better.
 
C02 gives you a chance though. Power extinguishers (type D) which are still widely recommended for 'Lithium fires' will only prevent other stuff around the battery catching fire, and that's only if the battery doesn't explode and blow all the power away. It's a misnomer to call it a fire extinguisher at that point....more of a "fire spread stopper".

C02 can stop fire already spreading to other areas, while having half a chance of stopping thermal runaway to adjacent cells, or at the very least buy you some time to get a hose and start dowsing with copious amounts of water.

I will never forget the time I stopped the spread of a smoldering fire taking hold in a mates ebike using tire inflating C02 cartridges. See below:

Obviously the cells themselves were not burning yet, but the C02 certainly helped stop the spread/ignition and cool things down (including fingers) and avoided a much worse outcome.

Cheers
I vividly remember taking a fire extinguishing class at my old place of work, and really wanting to use just CO2, because it would mean a lot less damage to the surrounding electronics equipment, but the problem was the fire would reignite over and over after applying CO2. Quite annoying. It just did not work, as much as I wanted it to. Powder was doing a much better job keeping the same type of fire extinguished. Of course with the stored energy in batteries you need to provide even more cooling to keep it from reigniting, so water really is your best option (unless you have plenty of CO2 cylinders available; most CO2 fire extinguishers are just too small).
 
That's a cool bike, dude. If you're ever thinking about swapping out the motor i'd consider switching to a hub motor because you can get a ton of torque out of a small hub with those 20" wheels ^_^
It'd old, but Dahon's welds haven't yet failed. Yes there's 23% more turning force where tyre meets tarmac using a 20" wheel than 26". I did want a rear hub motor, but the Brexit date limited my options ordering from China (made of unobtanium in UK at the time), and besides, 130mm rear dropouts makes things difficult without potentially hazardous spreading of the aluminium chainstays. Aluminium frames fatigue. To match or exceed the hill trailer hauling capability of my mid-drive conversion, I'd need a 48V motor and a somewhat more expensive 48V battery capable of discharging 22A continuously, which wouldn't be as fast on flat ground as the mid-drive. The BBS01B does both jobs well with a cheapo battery. Fast acceleration with 20" wheels, speedy enough, climbs all hills, it's a joy to ride. Folds for public transport.

(After the bit with Rapid Fatso. It's faster these days)
 
Last edited:
I vividly remember taking a fire extinguishing class at my old place of work, and really wanting to use just CO2, because it would mean a lot less damage to the surrounding electronics equipment, but the problem was the fire would reignite over and over after applying CO2. Quite annoying. It just did not work, as much as I wanted it to. Powder was doing a much better job keeping the same type of fire extinguished. Of course with the stored energy in batteries you need to provide even more cooling to keep it from reigniting, so water really is your best option (unless you have plenty of CO2 cylinders available; most CO2 fire extinguishers are just too small).

On Youtube, I've seen liquid nitrogen completely extinguish a small lithium fire - did look like an unfeasibly large quantity would be required to do the same to a flaming ebike battery. Not a practical solution for the home. Best rapidly expulserated via a window before the fact, at the first sign of temperature troubles.

 
Dude, this is a serious problem. We need to cut the world's energy use for transportation purposes massively. Going this route should be a non-option.
We're screwed. No wonder Musk is jumping planet. At this rate Bezo's dream of populating the moon and orbit to keep the Earth as a pristine nature reserve playground exclusively for the trillionaire class will never be realised unless... he engineers a more effective virus next time to kill everyone who doesn't have a well stocked private nuclear bunker. Yes, that's what happened in 2019, you heard it here first. Email jeff@amazon.com if you don't like it, he reads his emails. The final Tesla lithium-ion battery will be excreted by a robotic factory onto a desolate hot and dark unbreathable wasteland populated by a small smattering of in pain soon to be dead. Doomed I tell you, and so is that final Tesla battery. Therefore I'm all for soldium-ion batteries...

That said, any tech that yields a badass battery without cobalt, nickel, lithium? Better than gold.

...even if they're not badass.
 
Last edited:
Did everyone catch the part in the video that no matter how hard they tried Grin could not get a cell in their shop forced into a thermal runaway. Name brand cells are much safer than cheap and counterfeit cells.

Just an aside - When I charge in my basement, battery packs are placed in a latched galvanized metal box. Also, next to my workbench is a metal ash can with metal lid usually for cleaning out fireplaces but easy to drop any smoking/flaming/hot projects into that went bad. Old welding gloves are on my workbench also.
 
BEVs seem to average about 25 times that much pack, and they burn down a whole lot less often than petroleum stinkers. I think the risks are manageable, and mostly we just need to unplug our collective heads from our collective cloacas and stop using flashlight cells and knitting needles to do serious work.

That's the crazy stuff I was hoping to see here, but so far I have been disappointed.
 
In the bigger sodium ion size the weight to energy density is not bad when compared to the common molicel 42p

The 42p is 4.7 grams per watthour

Vs

8.9 grams per watthour for the sodium
Good for 10c


With the cost and safety of these especially they seem a real contender for larger vehicles and maybe smaller too with their true 10c.


9.2 grams per watthour with a123 lifepo4


Beating the common lifepo4 cell.
 
Last edited:
FYI, re extinguishers…
the Fire Dept have thrown everything they know at the Battery storage fire at Otay Mesa since it started a month ago.…..but i believe it is still burning and reigniting !
I would assume that these facilities incorporate every available fire detection and supression system available ?
 
In the bigger sodium ion size the weight to energy density is not bad when compared to the common molicel 42p

The 42p is 4.7 grams per watthour

Vs

8.9 grams per watthour for the sodium
Good for 10c


With the cost and safety of these especially they seem a real contender for larger vehicles and maybe smaller too with their true 10c.


9.2 grams per watthour with a123 lifepo4


Beating the common lifepo4 cell.

Very interesting!

46145 out of stock, but I can't wait for others to copy and improve the chemistry, lower cost so that I can build a cheap non-explodey sodium-ion ebike battery. My bike cares not about weight, but it takes exception to being on fire, understandably so. Hard to tell from the video what fully charged voltage of those cells is exactly - I'm wondering if I'd have to go 11s to prevent my BBS01B controller throwing a wobbly, at detection of substantially higher than 42V fully charged 12s. Also, how consistent is the chemistry of the cells? Can I get away with not using an active balancing BMS?



1718856104251.png



1718856221594.png
 
Last edited:
In the bigger sodium ion size the weight to energy density is not bad when compared to the common molicel 42p

The 42p is 4.7 grams per watthour

Vs

8.9 grams per watthour for the sodium
Good for 10c


With the cost and safety of these especially they seem a real contender for larger vehicles and maybe smaller too with their true 10c.


9.2 grams per watthour with a123 lifepo4


Beating the common lifepo4 cell.
The listing mentions that common forms are availalbe (18650, etc), but do you happen to know if they weigh more per the same size, or whether the above actually translates to about twice the volume for the same total energy storage?

It also mentions 3000 charge/discharge cycles, which is very encouraging.
 
The listing mentions that common forms are availalbe (18650, etc), but do you happen to know if they weigh more per the same size, or whether the above actually translates to about twice the volume for the same total energy storage?

It also mentions 3000 charge/discharge cycles, which is very encouraging.
If u look at the data sheets u can see. They’re not as energy dense as the larger size.

Makes me wonder why with this chemistry it’s a better energy to weight ratio than I see with ion or I think even lifepo4. Maybe I’m wrong but I think that’s the case. There’s barely any decent large format ion cells I know of.


Bigger cells for sure would be safer with less connections needed and easier to build…if only there were decent larger ion or lifepo4 cells. In my experience this is the case
 
Bigger cells for sure would be safer with less connections needed and easier to build…
Much more forgiving of bad welds using those knitting needles @Chalo hates, and with such high cycle life, safer when battery packs are disassembled and the cells inevitably are reused downstream, less polluting to manufacture and recycle.
 
Last edited:
Back
Top