Ebike battery fire

guerney

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I don't like where this might be heading - my pedelec being banned would be a right pain:


Brigade welcomes latest action on e-scooters by rail operators but urges caution on e-bikes

"
“While these are positive steps, our latest data shows that firefighters have attended 53 e-bike fires in London already in 2023, which is four times as many incidents as those involving e-scooters. ...

..... Given e-bikes are not included in the ban, we are also encouraging operators to consider whether they have adequate safety measures in place should an e-bike fire happen on their service.”
"



ScotRail BANS devices from its trains in major travel shake-up

"
This policy does not apply to personal mobility devices, power wheelchairs and electrically assisted bicycles or e-bikes, which are subject to UK legislation and standards. "

 
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Bogmonster666

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Jun 6, 2022
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They still can't replace lying politicians though
That's true enough, you need a special kind of ego to get us in this mess to start with. Since there has been media there have been people trying to use it to manipulate the masses, be that elected politicians or unelected 'politicians'. It's inevitable that you need to get your message to a wide audience and use a mixture of direct and subversive techniques. AI will make the generation of content for bots to spew so much more efficient and harder to track. I genuinely think social media risks being completely divided into 'dont use it because it is full of lies, propoganda and conspiracy theory', and 'look at that video that proves the Chinese have invaded Mars'. We are already well on that journey and many young people are now much more carefull about how they digest social media. And let's be honest, nobody under the age of 35 actually uses FB.

Deepfake will also be used more and more - the camera never lies - except that there may not be any need for a camera at all. It's only a matter of time untill there will be AI generated content that is personalized directly for you used in fields like advertising. Image an advert for a product or service that is based of a dataset about you, your age, ethnicity, political leaning, your hobbies and interests, your hopes and fears - AI will be used to generate things like marketing videos directed just at you as an individual, not just a broad demographic you belong to. How can any of this possibly go wrong?
 
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guerney

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Deepfakes will be harder to spot when they can blink and change pupil sizes.
 
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StuartsProjects

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One of the most significant worries about AI is that the large social media companies are pushing AI tools for the public to use.

Thier motivation of course is to make more and more money, so there will no-doubt be lots of subterfuge and hidden illegal uses of the data collected and sent.

Given that social media companies have a long history of abusing and illegally using data collected from the public, its simply insane to trust them with a tool like AI.
 
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Bogmonster666

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Jun 6, 2022
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so there will no-doubt be lots of subterfuge and hidden illegal uses of the data collected and sent
I'm sure that they have now learnt their lesson and we can take comfort in their new found ethical outlook

I think there is a general recognition in the big media players that AI will likely flip everything up in the air and there will be big winners and losers. Inoring AI is not an option, but fully embracing AI may be even worse for some. It may even be a catalyst for more folks to revert back to more traditional media outlets where it is more likely to get some basic authenticity and traceability?
 

saneagle

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Do remember that most all wires\cables for stuff like brake sensors, displays, throttle, PAS, Lights etc will have an individual ground connection in them.

Now, after a few years spent in electronics design and production, I can envisage circumstances where another wire shorted to ground could cause something to overheat.

Now when electronic components overheat, they do normally fail, and when they fail they can sometimes fail in a way that causes large amounts of current to flow which in turn can cause other components to fail etc, etc, etc.

Trying to guess what might happen when indivdual wires touch or fail is not so simple.

I could recant the tale of the time a tiny wire only about 0.2mm diameter was fracturing (physical shocks) in power supplies and on two ocaisions came very close to burning down the factory where I worked.
Wires burning away from the battery, or controllers having a quiet smoke is a nuicance, but not normally a major safety issue. It's wires adjacent to the battery burning that is the problem. Also, any short of the power wires between the cell-pack and BMS would be a very sangerous.

Look at this one of a BBS02 that spontaneously started burning. The controller MOSFETS sit at the bottom of the casing. The potting was compromised. The guy had been riding in the wet, presumably salty winter roads, and the conductive water reached either reached one of the MOSFETS and shorted it directly or reached a gate transistor and switched onthe MOSFETs, which are connected directly to the battery even when the bike is switched off. I guess the BMS limited the current, so the battery didn't over-heat. The end result was just the controller got damaged.
 

guerney

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Li-S Energy’s Lithium-Sulfur Cells Achieve 540 Wh/l Energy Density
The Australian company says its new 20-layer lithium-sulfur battery cells are safer, lighter and pack more energy.



Li-S Energy Achieves 45% Increase in Volumetric Energy Density With New Semi-Solid State Lithium Sulfur Battery


https://www.greencarreports.com/news/1139751_stellantis-evs-range-weight-lyten-lithium-sulfur-battery
 
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guerney

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They are banning e-scooters, e-unicycles, e-hoverboards and e-skateboards, not e-bikes, not a bad shout as far as I'm concerned.
I fear as insurance costs increase, ebikes may be next - I'd have to buy a much bigger battery...
 

guerney

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Iron-Air Batteries Are Here. They May Alter the Future of Energy.
Battery tech is now entering the Iron Age.

" Using a principle called “reverse rusting,” the cells “breathe” in air, which transforms the iron into iron oxide (aka rust) and produces energy. To charge it back up, a current reverses the oxidation and turns the cells back into iron. "

 

guerney

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Two men clinging to 16th floor window of burning tower block heroically saved
" During the fire, which was caused by an electric bike inside a top floor flat, 90 people were evacuated from the building with eight taken to hospital for treatment. "
 

guerney

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New takedown powers are needed to protect consumers from unsafe goods sold online

Several domestic fires linked to e-bike chargers and other faulty goods have seen homes burn and lives put at risk.

 

WheezyRider

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Apr 20, 2020
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Something does need to be done about chargers being sold on online. I think they are one of the biggest causes of fires. Then also, there should be a system of unique connectors on the output of the charger for a given voltage. It's too easy to connect say a 48V charger to a 36 V battery at the moment. Then, what is a 48V charger? One for 13S or 14S? Connect the wrong one and you could be in trouble. Add to that, it seems many chargers no longer have tuning pots in the output circuit to ensure the voltage is within spec. The most recent charger I bought gave a spec of 42V +/- 0.3 V. 42.3V will overcharge the cells, reducing life. 41.7 is probably not enough to induce the balance phase of most BMS, which could lead to issues. Several chargers I have taken apart have also had solder quality issues that could lead to failure.

I do think there needs to be some legislation on minimum standards for chargers, so they are fit for the purpose they were intended.
 

saneagle

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Something does need to be done about chargers being sold on online. I think they are one of the biggest causes of fires. Then also, there should be a system of unique connectors on the output of the charger for a given voltage. It's too easy to connect say a 48V charger to a 36 V battery at the moment. Then, what is a 48V charger? One for 13S or 14S? Connect the wrong one and you could be in trouble. Add to that, it seems many chargers no longer have tuning pots in the output circuit to ensure the voltage is within spec. The most recent charger I bought gave a spec of 42V +/- 0.3 V. 42.3V will overcharge the cells, reducing life. 41.7 is probably not enough to induce the balance phase of most BMS, which could lead to issues. Several chargers I have taken apart have also had solder quality issues that could lead to failure.

I do think there needs to be some legislation on minimum standards for chargers, so they are fit for the purpose they were intended.
The BMS has over-charge protection on every cell, which would protect a battery against those problems.
 
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WheezyRider

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The BMS has over-charge protection on every cell, which would protect a battery against those problems.
I hope so, but it's one thing I haven't put it to the test :). The cut out voltage seems to be set to between 4.25 and 4.3V per cell. It only takes 4.35 V/cell to start plating metallic lithium, which could lead to a fire. It's such a fine margin, and you have to hope the control electronics are calibrated properly.

It's also a case of what is the maximum design over voltage of the BMS? Eg...if 50V max components are used and then a 14S charger at 58.8V is applied...

Leaving it all up to the BMS to sort out means only one fail safe. Is that enough?
 

WheezyRider

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Here is a screen shot of the spec from a typical Daly BMS

52780

So the cut off is set to 4.25 +/- 0.05 V. So it could be as low as 4.2V or as much as 4.3V. It would be interesting to see how this works. So at the bottom end, 4.2V - would end up cutting out charging as soon as one cell reached 4.2V. In that case, balancing probably wouldn't work properly as it would not give enough time for low cells to reach 4.2V. Or at the top end, some cells could be reaching 4.3V, which we know drastically reduces cell life, to perhaps as little as 100 cycles or so. Then there is the ambient temperature of the system. At higher temperatures, this can shift electrode potentials so that lower voltages are needed. If 4.35V/cell is the critical point, I'm not enough of an electrochemistry expert to know what temperature is needed to shift that to 4.3V. Five hundredths of a volt isn't much. I would be interested to hear from someone who has an answer to that.

I suppose this is why packs often fail before their time. You have one good bank of cells in your pack. The BMS allows it to go to 4.3V, while the other banks catch up. After 100 cycles, the previously good bank goes bad and it takes the whole pack with it. No fire, but a premature death of the pack.
 

saneagle

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Here is a screen shot of the spec from a typical Daly BMS

View attachment 52780

So the cut off is set to 4.25 +/- 0.05 V. So it could be as low as 4.2V or as much as 4.3V. It would be interesting to see how this works. So at the bottom end, 4.2V - would end up cutting out charging as soon as one cell reached 4.2V. In that case, balancing probably wouldn't work properly as it would not give enough time for low cells to reach 4.2V. Or at the top end, some cells could be reaching 4.3V, which we know drastically reduces cell life, to perhaps as little as 100 cycles or so. Then there is the ambient temperature of the system. At higher temperatures, this can shift electrode potentials so that lower voltages are needed. If 4.35V/cell is the critical point, I'm not enough of an electrochemistry expert to know what temperature is needed to shift that to 4.3V. Five hundredths of a volt isn't much. I would be interested to hear from someone who has an answer to that.

I suppose this is why packs often fail before their time. You have one good bank of cells in your pack. The BMS allows it to go to 4.3V, while the other banks catch up. After 100 cycles, the previously good bank goes bad and it takes the whole pack with it. No fire, but a premature death of the pack.
If you and Guerney got married and had kids, Heaven help them!