Battery Fires

[Woosh]

The mini XLR connector is relatively new for 48V battery, you can't use the 48V charger in a 36V battery. There are adapters for the new 48V charger to be used with old 48V batteries with jack socket but we won't sell you the adapter unless we know exactly why you need it.
The new connector is not as good as an intelligent CAN-bus charger but it makes mistakes far less likely.

 

[soundwave]

got mini xlr on my 490s

 

[MikelBikel]

 

[lenny]

Calls for big e-bike rule change in Nottingham after spate of serious fires

Calls for big e-bike rule change in Nottingham after spate of serious fires

Nottingham City Council will write to the government to try and tackle the issue

www.nottinghampost.com

 

[AntonyC]

Two fires in nearly two years, one with a cause the govt had already acted on. A Nottingham councillor (Labour) will write to the fire minister (Nottingham North, Labour).

I smell the dead hand of Electrical Safety First on the faltering UK e-cycle industry, ah yes, line 15.

 

[Tony1951]

This issue is very much out of perspective in terms of overall risk.

UK wide fire service data shows that they attended 211 e-bike fires, 18,545 vehicle fires and a total of 136,702 fires. This makes it abundantly clear that the e-bike incendiary device crisis is a complete scam got up by excited anti-cycling fanatics and the scum press.

https://www.theguardian.com/news/2025/jun/05/record-number-of-ebike-fires-in-uk-prompts-renewed-risk-warnings

Just one example. There are many.

Ebike fires are a tiny part of a much bigger fire problem in the UK.

It is a joke that so much time is wasted here going on and on about this.

There are a lot of people on this forum and they report all kinds of faults. Every kind of technical glitch is featured here.

If their bike caught fire, they would be reporting it, but the only case I have ever seen myself reported on here of an adverse battery incident actually happening to a member, was reported shamefacedly, by a chap who admitted he was dismantling an old battery, and he punctured it with a metal screwdriver while prying off the nickel strips to home recycle the cells. The battery reacted badly and he burned himself.

Lithium batteries are perfectly safe unless you abuse them horribly. So are petrol, matches, mains electricity, and dozens of home appliances - which by the way are FAR FAR more likely to burn your house down and kill your family.

If you abuse any technology - including kitchen knives, garden tools and chainsaws, you will likely come to regret it. Did I ever tell you about the time I caught my jumper sleeve with one of those flat woodworking bits in my 400watt black and decker........

The press - especially the trashy end of it, continually hypes e-bike fires and dangerous lithium batteries. They are no more dangerous than any and every electrical socket in your house. In fact the potential danger of abusing any electrical socket is much more serious. But of course, the danger only ever comes when you abuse the thing.

There are people here who are doing the same dirty work as the trashy press - exaggerating the risk and ruining the reputation of a useful technology. Unkind people might call them 'useful fools', doing the work of the Daily Mail, Telegraph and other trashy rags that hate all cycling - especially e-bikes.


If you are anything like me, you have many lithium batteries in your house.

I have:

• two e-bikes
• a dyson battery vacuum cleaner
• numerous lithium powered radios, computer laptops, mobile phones
• a ten amp lithium power bank
• A number of salvaged vape batteries (now equipped with TP4056 charge discharge controllers, used for small electronic or electrical projects
• a hedge trimmer
• two screwdriver tools

None of them have ever given me the slightest trouble.

Maybe this is because like the matches, lighters, petrol, the gallon of naptha that I have and the half gallon of 99.9% isopropyl alcohol, the butane gas blow lamp, gas hob, gas central heating, log burner and other potentially hazardous articles I use, I treat them carefully.

I am not a moron. Morons are beyond help and will kill themselves in a whole variety of ways, or maim themselves or others while using a chain saw.

We KNOW where the e-bike problem lies - it is with morons ill treating e-bikes and making franken-bikes which are pretty much wheeled incendiary bombs, usually contrived out of rubbish for doing delivery work, where the bike is overpowered, over used, and over charged, and may even as Saneagle pointed out - have its BMS deliberately cut out or by-passed to allow the above abuses to take place at an even greater rate than before.

I suggest we should stop doing the work of the anti-cycling press.

As stored energy devices go, a battery is a pretty safe form of concentrated energy. Certainly is compared with compressed air, petroleum, gas and dynamite.


Moron blows up houses messing with gas



Face of the aforesaid moron



Morons can make anything dangerous. Keep them away from your toolbox and cutlery drawer and make sure they never get to use power tools. Above all - don't buy your e-bike from one, and don't let one modify an e-bike you already own.

 

[Tony1951]

Another period of electrical technophobia.

Wired Fears: Electricity and Technophobia in the Nineteenth Century

Society usually accompanies the introduction of new technologies with both excitement and suspicion, being simultaneously driven by an enthusiasm for the possibility of improvement, as well as prof…

www.shellsandpebbles.com

 

[Baz the balloon man]

For the price I find Hailong batteries to be ok , no where near as good as the ones Giant use but more than half the price !!

As my missis keeps reminding me

“What you Pay “” but then she is really into brands I like a Bargin

I

 

[saneagle]

Most of what you guys say is true, but there's always the chance that a battery had a wire out of place or something like that when it was manufactured. When you look inside a lot of batteries, you can see the difference. Some are very well organised and tidy, others are all over the place, though any of them could have a mistake in it.

One problem I saw in an otherwise very tidy silver fish battery was that the wires were crossed over at the bottom. There's a rubber block between the cell-pack and the connector that the whole weight of the cell-pack rests on. Where the wires crossed under the rubber block left a substantial imprint in the block. I recognised that to be very dangerous because if you dropped the battery, the impact on the wires from the weight of the cell-pack could easily break the insulation, so I uncrossed them and arranged them in a neater and safer way. A couple of years later, I saw that video of the guy in the lift. He was bringing his battery up to his appartment, presumably to charge. The battery burst into flames and cremated him as soon as the door shut. What I had seen in my battery was probably the same in his, and when he dropped it too heavily onto the concrete while he waited for the lift probably started the short-circuit that caused it to blow up.

 

[Nealh]

One cannot simply ignore lion battery fire risks as once they start they are fierce and difficult to extinguish.
Here another fire last week, the diy bikes battery left to charge overnight and well in to the following morning.
Again probably not an inherently dangerous battery parse but certainly charging process involved is the likely cause ?

MSN

 

[AntonyC]

Lithium batteries are perfectly safe unless you abuse them horribly.

Certainly ebike fires are hyped but the situation is unacceptable. Quality issues are always possible as @saneagle says, and not all damage occurs through moronic abuse. A few batteries do catch fire when charged for too long or with the wrong charger and that's failure by design: both are easily foreseeable commonplace mishandling and are preventable failures.

Unlike e-motos, e-cycles and scooters are small enough to bring indoors, their batteries need more capacity than most other appliances and unlike camping power banks, bikes need high power density in both volume and weight. That three way intersection increases risk and impact, while also pointing to several ways to address them.

 

[Tony1951]

One cannot simply ignore lion battery fire risks as once they start they are fierce and difficult to extinguish.
Here another fire last week, the diy bikes battery left to charge overnight and well in to the following morning.
Again probably not an inherently dangerous battery parse but certainly charging process involved is the likely cause ?

MSN

Yes - Leaving the bike on charge over night and well into the next day is an idiotic risk to take. Idiotic if you have been suitably informed about the risks of treating this kind of lithium battery badly. It is clear that a lot of people have never been properly informed about what they are buying and using. These things are being bundled out of the doors of various sales businesses without impressing on the users how dangerous they can be if abused in ways which for many naive users don't seem abusive at all.

But there is something else to be said as well.

This fire caused by over charging, ought never to have happened unless the charger and the BMS were both faulty. First off - the charger should never have taken the battery voltage high enough to cause heating and ignition, and secondly the BMS should have cut off charging at the maximum threshold voltage of the battery.

I imagine decently made Chinese chargers and BMSs should have prevented this and there are two safety devices inline designed to do exactly that. I don't know what the failure rate is on such devices - probably one in a thousand (*1), so for both to fail and cause the fire seems extremely unlikely.

*1
I made that figure up as a likely estimate.

 

[Nealh]

As with most of these fires the actual charger or battery involved are the unknown factor .
Charging of devices whether ebike battery or phone ,etc ,etc should be monitored and certainly not left to do it's own thing whilst asleep.
Lucky for this lady and her boy that the fire didn't occur at night.

It is a stark reminder to the uneducated that they are playing a risky game by ignoring some simple safety facts.

 

[saneagle]

Yes - Leaving the bike on charge over night and well into the next day is an idiotic risk to take. Idiotic if you have been suitably informed about the risks of treating this kind of lithium battery badly. It is clear that a lot of people have never been properly informed about what they are buying and using. These things are being bundled out of the doors of various sales businesses without impressing on the users how dangerous they can be if abused in ways which for many naive users don't seem abusive at all.

But there is something else to be said as well.

This fire caused by over charging, ought never to have happened unless the charger and the BMS were both faulty. First off - the charger should never have taken the battery voltage high enough to cause heating and ignition, and secondly the BMS should have cut off charging at the maximum threshold voltage of the battery.

I imagine decently made Chinese chargers and BMSs should have prevented this and there are two safety devices inline designed to do exactly that. I don't know what the failure rate is on such devices - probably one in a thousand (*1), so for both to fail and cause the fire seems extremely unlikely.

*1
I made that figure up as a likely estimate.

When current passes through a battery, it heats up due to the internal resistance and in proportion to the square of the current. In other words, the heat produced at 20A is 100 times the heat produced at 2A.

When you're riding the bike, the battery is in a stream of air that aids cooling, and the current is very much stop-start, so there's plenty of chance for the battery to cool down between bursts. When you're charging on a bench or on a stationary bike, the current is constant and prolonged. The temperature that the battery reaches depends on its ability to shed heat, which is not that good when it's insulated by plastic, stationary and the ambient temperature is already high. Every battery is different. The only way you know if it's a problem is if you stick your hand on it after some charging time. I can imagine a lot of delivery drivers, who charge with a 2A charger and never feel the battery getting warm, so they get the idea to speed things up by using a 5A or 10A charger, which is going to produce 6 times or 50 times more heat in the battery. I've felt some batteries getting warm when charging at 2A. It sends shivers down my spine thinking about pushing 50 or 100 times that heat into them.

An excellent 18650 cell has an internal resistance of around .05 Ohms, though normal ones are closer to 0.1 Ohms. A 48v 20A battery would be typically 13x6 = 78 cells. The total resistance for excellent cells would be 13 x 0.05/6 = 0.11 Ohms. If you charge it at 2A, the heat produced would be 0.44w and if you charge at 20A, it would be 44W. If it had normal or worn cells, it would be double that, so 88W. 88W is too much heat to try and lose from a battery being charged in an insulated bag, so maybe that's why all those bag batteries catch fire.

 

[AntonyC]

I think it was more likely the BMS. In ball-park figures, typical pack resistance = 200mOhm (approx and varies widely), 10A -> 20W of heat into 3kg of cells x 0.8J/gK. That's like heating a kettle (1.5 l x 4.2J/gK) with 50W, lots of time to cool as it heats. As it nears full charge the current and heating's a lot less and this battery made it to late morning. If the BMS failed to cut off when balanced the cells would trickle charge at top voltage when dendrites grow fastest. Or, as upthread, all manner of other causes.

My Woosh battery seems to charge to 4.15V rather than 4.2V per cell. That would mean I'm missing out on a mile of range in exchange for being safer in relation to this kind of fault, and I'm more than happy with that.