On 4/13/2024 3:20 AM, John Robertson wrote:
> On 2024/04/12 10:26 a.m., bitrex wrote:
>> On 4/12/2024 1:07 PM, John Robertson wrote:
>>> On 2024/04/12 9:52 a.m., john larkin wrote:
>>>> On Fri, 12 Apr 2024 12:22:00 -0400, bitrex <user@example.net> wrote:
>>>>
>>>>> On 4/12/2024 10:04 AM, Bill Sloman wrote:
>>>>>> On 12/04/2024 9:16 pm, Carlos E.R. wrote:
>>>>>>> On 2024-04-12 07:19, Bill Sloman wrote:
>>>>>>>> On 9/04/2024 3:03 am, Jeroen Belleman wrote:
>>>>>>>>> On 4/8/24 18:35, John Larkin wrote:
>>>>>>>>>> https://www.bbc.com/news/uk-england-london-68744317
>>>>>>>>>>
>>>>>>>>>> It doesn't look like that one was charging.
>>>>>>>>>>
>>>>>>>>>> Lithium battery fires are a big deal in New York too.
>>>>>>>>>>
>>>>>>>>>> San Fancisco is swarming with illegal, unlicensed electric
>>>>>>>>>> scooters,
>>>>>>>>>> surfboards, wheelie things, bikes, and motorcycles.
>>>
>>> As are most cities with access to Amazon/eBay...(no regulations on
>>> what people can sell on these platforms)
>>>
>>> ...
>>>>> And fretting about the hazards of exploding batteries with 300 million
>>>>> guns floating around is pretty schizophrenic. Compared to being
>>>>> injured
>>>>> by an exploding bike (or shot by a stranger for that matter) your
>>>>> chances of being shot by a police officer are at least the same, or
>>>>> higher.
>>>>
>>>> About 1300 people were killed by police in the US last year, out of a
>>>> population of 333 million, about 4 PPM. Cops rarely shoot polite
>>>> law-abiding citizens; don't threaten people, especially cops, with
>>>> guns or knives.
>>>
>>> Here in Canada the average number of people killed by police annually
>>> is just under 40 per year since 2011. Out of a population of roughly
>>> 40,000,000 or 1 PPM in other words.
>>>
>>> Perhaps our gun laws do make a difference.
>>>
>>> John :-#)#
>>
>> Traffic accidents kill about 50k Americans per year, firearms in the
>> same ballpark, and Covid is still dropping 500-1k per day.
>
> US death rate from Covid is around 30/day - not 500 or more! Which is
> now about the same as Canada.

Ope, meant per month, not per day! :B

> Deaths per 100,000 from Covid in Canada was about 1/2 the rate of the
> US. Most of those higher rates of death occurred under the previous US
> administration.
>
> https://www.worldometers.info/coronavirus/country/us/

On 13/04/2024 06:55, Bill Sloman wrote:
> On 13/04/2024 12:17 am, John Larkin wrote:
>> On Fri, 12 Apr 2024 09:55:19 +0100, liz@poppyrecords.invalid.invalid
>> (Liz Tuddenham) wrote:
>>
>>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>>
>>>> ... if
>>>> it had a safe place to dissipate the stored energy.
>>>
>>> What if it didn't?
>>
>> And what if cheap Chinese batteries weren't all designed by geniuses
>> like Sloman?
>
> It doesn't take genius to design a decent battery monitoring system, and
> manufacturers who sell dangerous products get sued, and banned from
> selling into markets with even minimal consumer protection legislation.
> Even the US finally banned tetra-ethyl lead as a gasoline additive.
>

Not entirely. It is still allowed for general aviation.

John

On Fri, 12 Apr 2024 10:07:59 -0700, John Robertson <jrr@flippers.com>
wrote:

>On 2024/04/12 9:52 a.m., john larkin wrote:
>> On Fri, 12 Apr 2024 12:22:00 -0400, bitrex <user@example.net> wrote:
>>
>>> On 4/12/2024 10:04 AM, Bill Sloman wrote:
>>>> On 12/04/2024 9:16 pm, Carlos E.R. wrote:
>>>>> On 2024-04-12 07:19, Bill Sloman wrote:
>>>>>> On 9/04/2024 3:03 am, Jeroen Belleman wrote:
>>>>>>> On 4/8/24 18:35, John Larkin wrote:
>>>>>>>> https://www.bbc.com/news/uk-england-london-68744317
>>>>>>>>
>>>>>>>> It doesn't look like that one was charging.
>>>>>>>>
>>>>>>>> Lithium battery fires are a big deal in New York too.
>>>>>>>>
>>>>>>>> San Fancisco is swarming with illegal, unlicensed electric scooters,
>>>>>>>> surfboards, wheelie things, bikes, and motorcycles.
>
>As are most cities with access to Amazon/eBay...(no regulations on what
>people can sell on these platforms)
>
>...
>>> And fretting about the hazards of exploding batteries with 300 million
>>> guns floating around is pretty schizophrenic. Compared to being injured
>>> by an exploding bike (or shot by a stranger for that matter) your
>>> chances of being shot by a police officer are at least the same, or higher.
>>
>> About 1300 people were killed by police in the US last year, out of a
>> population of 333 million, about 4 PPM. Cops rarely shoot polite
>> law-abiding citizens; don't threaten people, especially cops, with
>> guns or knives.
>
>Here in Canada the average number of people killed by police annually is
>just under 40 per year since 2011. Out of a population of roughly
>40,000,000 or 1 PPM in other words.
>
>Perhaps our gun laws do make a difference.
>
>John :-#)#

The population mix makes a bigger difference. Bad guys will always
find guns.

On 14/04/2024 1:14 am, Liz Tuddenham wrote:
> Bill Sloman <bill.sloman@ieee.org> wrote:
>
>> On 13/04/2024 3:39 am, Liz Tuddenham wrote:
>>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>>
>>>> On 12/04/2024 6:55 pm, Liz Tuddenham wrote:
>>>>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>>>>
>>>>>> ... if
>>>>>> it had a safe place to dissipate the stored energy.
>>>>>
>>>>> What if it didn't?
>>>>
>>>> Then it probably needs to include a louder hooter and brilliant flashing
>>>> lights to serve the same purpose, if more slowly than a purpose designed
>>>> dissipator.
>>>>
>>>>>> ..was being looked
>>>>>> after by somebody who ignored the early warnings.
>>>>>
>>>>> That includes 99% of battery users who wouldn't know what to do it they
>>>>> noticed the warnings or wouldn't be able to do it anyway.
>>>>
>>>> A voice message could be pretty explicit. All the message needs to say
>>>> is to move the battery outside to where it can't do much damage if it
>>>> bursts into flames. EV car batteries are big enough that that's quite a
>>>> way, but cars are designed to move appreciable distances.
>>>
>>> It's not really a very good selling point. "Oh, by the way, this model
>>> has the latest upgrade and tells you when it is going to explode, so you
>>> can get out of the way".
>>
>> You don't seem to have been paying attention. If you deal with the
>> warning by discharging the battery, and making it safe, it won't explode.
>
>
> Who it the 'you' in that sentence?

You personally.

> Do you mean the average user, in
> which case this is a hopeless scenario as most users of batteries
> wouldn't have a clue.
>
> Until recently batteries have been inherently safe: unless you did
> something stupid they were unlikely to give any trouble. You are now
> supporting a type of battery that is inherently unsafe and will catch
> fire or explode unless the user takes some positive action.

But happens to offer a much higher energy density.

It takes a long time to degrade to the point where it can catch fire or
explode, and the degradation is entirely detectable.

> Even if the user delegates this action to an automated system there is no guarantee
> that the action will be taken every time it is needed.

And the brakes on your car don't always work, but we do seem to be
willing to live with that.

> 'Safety' that depends on taking a positive action to prevent a disaster
> is not safe at all.

But we live with that, when the advantages are proportionate to the risk.

--
Bill Sloman, Sydney

On 14/04/2024 2:35 am, John Larkin wrote:
> On Sat, 13 Apr 2024 16:14:07 +0100, liz@poppyrecords.invalid.invalid
> (Liz Tuddenham) wrote:
>
>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>
>>> On 13/04/2024 3:39 am, Liz Tuddenham wrote:
>>>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>>>
>>>>> On 12/04/2024 6:55 pm, Liz Tuddenham wrote:
>>>>>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>>>>>
>>>>>>> ... if
>>>>>>> it had a safe place to dissipate the stored energy.
>>>>>>
>>>>>> What if it didn't?
>>>>>
>>>>> Then it probably needs to include a louder hooter and brilliant flashing
>>>>> lights to serve the same purpose, if more slowly than a purpose designed
>>>>> dissipator.
>>>>>
>>>>>>> ..was being looked
>>>>>>> after by somebody who ignored the early warnings.
>>>>>>
>>>>>> That includes 99% of battery users who wouldn't know what to do it they
>>>>>> noticed the warnings or wouldn't be able to do it anyway.
>>>>>
>>>>> A voice message could be pretty explicit. All the message needs to say
>>>>> is to move the battery outside to where it can't do much damage if it
>>>>> bursts into flames. EV car batteries are big enough that that's quite a
>>>>> way, but cars are designed to move appreciable distances.
>>>>
>>>> It's not really a very good selling point. "Oh, by the way, this model
>>>> has the latest upgrade and tells you when it is going to explode, so you
>>>> can get out of the way".
>>>
>>> You don't seem to have been paying attention. If you deal with the
>>> warning by discharging the battery, and making it safe, it won't explode.
>>
>>
>> Who it the 'you' in that sentence? Do you mean the average user, in
>> which case this is a hopeless scenario as most users of batteries
>> wouldn't have a clue.
>>
>> Until recently batteries have been inherently safe: unless you did
>> something stupid they were unlikely to give any trouble. You are now
>> supporting a type of battery that is inherently unsafe and will catch
>> fire or explode unless the user takes some positive action. Even if the
>> user delegates this action to an automated system there is no guarantee
>> that the action will be taken every time it is needed.
>>
>> 'Safety' that depends on taking a positive action to prevent a disaster
>> is not safe at all.
>
> References say that a tiny separator defect spreads radially at
> centimeters per second.

But you can't provide a link to any such reference.

Google threw up a paper on using airflow to test test battery separators
before they were assembled into a battery, so your defect is going to be
present in new cells, and detectable before they are into assembled
batteries of cells.

> Any somehow-sensed defect will explode in
> flames in well under a minute, from the bad cell into the whole pack.
> See Youtube examples... smoke to explosion in seconds.

Youtube is full of half-baked rubbish, and you are sucker for that.
> If I heard an alarm from a lithium battery pack, I wouldn't try to fix
> it, I'd run in the opposite direction. What automated system could
> discharge an 80 KWH battery pack in a few seconds? Or even 1 KWH?

It doesn't have to discharge it in a few seconds. An increased
self-discharge rate is detectable long before a cell gets to the point
of thermal runaway - the local temperature has to get up to between
130C and 160C - depending on battery type - before it can move into
thermal run-away, so you have plenty of time to make it safe.
> And a defect sensor would have to constantly snoop every cell of a
> pack. A typical Tesla might have 7000 cells.

It doesn't. It has to snoop the battery core temperature and compare it
with battery surface temperature. A few sensors spread around the core
would let you pick up the existence of hot spots - you wouldn't need to
work out exactly where they were.

The Telsa battery monitors it own core temperature and has built in
resistive heaters to warm it up when outside temperatures are too low to
let it deliver full power at start-up.

--
Bill Sloman, Sydney

Bill Sloman <bill.sloman@ieee.org> wrote:

> On 14/04/2024 1:14 am, Liz Tuddenham wrote:
> > Bill Sloman <bill.sloman@ieee.org> wrote:
> >
> >> On 13/04/2024 3:39 am, Liz Tuddenham wrote:
> >>> Bill Sloman <bill.sloman@ieee.org> wrote:
> >>>
> >>>> On 12/04/2024 6:55 pm, Liz Tuddenham wrote:
> >>>>> Bill Sloman <bill.sloman@ieee.org> wrote:
> >>>>>
> >>>>>> ... if
> >>>>>> it had a safe place to dissipate the stored energy.
> >>>>>
> >>>>> What if it didn't?
> >>>>
> >>>> Then it probably needs to include a louder hooter and brilliant flashing
> >>>> lights to serve the same purpose, if more slowly than a purpose designed
> >>>> dissipator.
> >>>>
> >>>>>> ..was being looked
> >>>>>> after by somebody who ignored the early warnings.
> >>>>>
> >>>>> That includes 99% of battery users who wouldn't know what to do it they
> >>>>> noticed the warnings or wouldn't be able to do it anyway.
> >>>>
> >>>> A voice message could be pretty explicit. All the message needs to say
> >>>> is to move the battery outside to where it can't do much damage if it
> >>>> bursts into flames. EV car batteries are big enough that that's quite a
> >>>> way, but cars are designed to move appreciable distances.
> >>>
> >>> It's not really a very good selling point. "Oh, by the way, this model
> >>> has the latest upgrade and tells you when it is going to explode, so you
> >>> can get out of the way".
> >>
> >> You don't seem to have been paying attention. If you deal with the
> >> warning by discharging the battery, and making it safe, it won't explode.
> >
> >
> > Who it the 'you' in that sentence?
>
> You personally.
>
> > Do you mean the average user, in
> > which case this is a hopeless scenario as most users of batteries
> > wouldn't have a clue.
> >
> > Until recently batteries have been inherently safe: unless you did
> > something stupid they were unlikely to give any trouble. You are now
> > supporting a type of battery that is inherently unsafe and will catch
> > fire or explode unless the user takes some positive action.
>
> But happens to offer a much higher energy density.
>
> It takes a long time to degrade to the point where it can catch fire or
> explode, and the degradation is entirely detectable.
>
> > Even if the user delegates this action to an automated system there is
> > no guarantee that the action will be taken every time it is needed.
>
> And the brakes on your car don't always work, but we do seem to be
> willing to live with that.
>
> > 'Safety' that depends on taking a positive action to prevent a disaster
> > is not safe at all.
>
> But we live with that, when the advantages are proportionate to the risk.

My van has dual hydraulic systems for the footbrake, a mechanical
handbrake and even gears that could slow it down in an emergency. If I
park it somewhere, the chance of it crashing into something while I am
not there to stop it is very small indeed, I don't need to take any
positive action.

I suspect the number of spontaneous fires of vehicles with lithium
batteries is far higher in relation to the number on the roads than the
number of spontaneous runaways and crashes of diesel and petrol
vehicles. In addition there is the same risk of brake failure on an
electric vehicle - even more so if it has an electric parking brake
which is the driver cannot operate quickly in an emergency.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

On 14/04/2024 6:43 am, Carlos E.R. wrote:
> On 2024-04-12 16:04, Bill Sloman wrote:
>> On 12/04/2024 9:16 pm, Carlos E.R. wrote:
>>> On 2024-04-12 07:19, Bill Sloman wrote:
>>>> On 9/04/2024 3:03 am, Jeroen Belleman wrote:
>>>>> On 4/8/24 18:35, John Larkin wrote:
>>>>>> https://www.bbc.com/news/uk-england-london-68744317
>>>>>>
>>>>>> It doesn't look like that one was charging.
>>>>>>
>>>>>> Lithium battery fires are a big deal in New York too.
>>>>>>
>>>>>> San Fancisco is swarming with illegal, unlicensed electric scooters,
>>>>>> surfboards, wheelie things, bikes, and motorcycles.
>>>>>
>>>>> As the energy density of batteries goes up, failures will
>>>>> become more spectacular. It's not a good idea to store
>>>>> both oxidizer and fuel in close proximity in the same
>>>>> container. It's a recipe for an explosive.
>>>>
>>>> Lithium batteries don't explode spontaneously.
>>>>
>>>> The "explosion" is actually the last stage in a process that starts
>>>> when the batteries start self-discharging more rapidly than they
>>>> should, which warms them up a little.
>>>>
>>>> Any properly designed battery management system monitors this
>>>> self-heating, with temperature sensors at the core of the battery,
>>>> and on it's surface.
>>>>
>>>> If the battery gets hot enough, the higher temperature can lead to a
>>>> higher discharge rate, and at a battery temperature between 130C and
>>>> 160C which depends on the battery chemistry, the process can run
>>>> away leading to something that looks like an explosion.
>>>>
>>>> Any properly designed designed battery management system would warn
>>>> the user when this were incipient and would start discharging the
>>>> battery if it had a safe place to dissipate the stored energy.
>>>>
>>>> It follows that any lithium battery pack that explodes either didn't
>>>> have a properly designed battery management system, or was being
>>>> looked after by somebody who ignored the early warnings.
>>>>
>>>> All this is too complicated for John Larkin to keep in mind - we've
>>>> discussed it here often enough that he should know it by now.
>>>
>>> Or the battery wasn't attended.
>>
>> Warning systems can be designed to be quite attention getting.
>>
>>> Battery fires have happened when nobody was near the battery; maybe
>>> charging.
>>
>> A proper battery management system wouldn't let you charge a battery
>> that had got close to going into thermal runaway
>>
>>> Here, several cities have prohibited personal electric things with
>>> wheels from entering the urban public transport system after a few
>>> fires.
>>
>> A slightly better informed city administration could adopt a more
>> sensible rule. Personal electric things with wheels can be designed to
>> be quite unlikely to catch on fire. One's that aren't shouldn't be on
>> sale in the first place, and would be prohibited imports in any
>> sensible region.
>
> It is the only thing they can do until the manufacturers create machines
> that do not catch fire putting the entire metro line out of service. It
> is not the city transport business or job to mandate what others should
> do, or what other regulators do to regulate proper battery building.
> They simply have to protect themselves and their users.
>
> (Oh, no guns around here.)

Most manufacturers produce stuff that doesn't blow up. The rational
approach is to ban only the stuff that might.

> And yes, of course it is a pain. The combination of a personal transport
> device and public transportation was working wonderfully for many. You
> get from home to the station with your wheelie in minutes, cross the
> city in minutes underground, arrive at job place in minutes from the
> station using the wheelie again.

So ban the cheap junk wheelies that are known to pose a risk of catching
fire and exploding.

--
Bill Sloman, Sydney

On 14/04/2024 4:38 pm, Liz Tuddenham wrote:
> Bill Sloman <bill.sloman@ieee.org> wrote:
>
>> On 14/04/2024 1:14 am, Liz Tuddenham wrote:
>>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>>
>>>> On 13/04/2024 3:39 am, Liz Tuddenham wrote:
>>>>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>>>>
>>>>>> On 12/04/2024 6:55 pm, Liz Tuddenham wrote:
>>>>>>> Bill Sloman <bill.sloman@ieee.org> wrote:
>>>>>>>
>>>>>>>> ... if
>>>>>>>> it had a safe place to dissipate the stored energy.
>>>>>>>
>>>>>>> What if it didn't?
>>>>>>
>>>>>> Then it probably needs to include a louder hooter and brilliant flashing
>>>>>> lights to serve the same purpose, if more slowly than a purpose designed
>>>>>> dissipator.
>>>>>>
>>>>>>>> ..was being looked
>>>>>>>> after by somebody who ignored the early warnings.
>>>>>>>
>>>>>>> That includes 99% of battery users who wouldn't know what to do it they
>>>>>>> noticed the warnings or wouldn't be able to do it anyway.
>>>>>>
>>>>>> A voice message could be pretty explicit. All the message needs to say
>>>>>> is to move the battery outside to where it can't do much damage if it
>>>>>> bursts into flames. EV car batteries are big enough that that's quite a
>>>>>> way, but cars are designed to move appreciable distances.
>>>>>
>>>>> It's not really a very good selling point. "Oh, by the way, this model
>>>>> has the latest upgrade and tells you when it is going to explode, so you
>>>>> can get out of the way".
>>>>
>>>> You don't seem to have been paying attention. If you deal with the
>>>> warning by discharging the battery, and making it safe, it won't explode.
>>>
>>>
>>> Who it the 'you' in that sentence?
>>
>> You personally.
>>
>>> Do you mean the average user, in
>>> which case this is a hopeless scenario as most users of batteries
>>> wouldn't have a clue.
>>>
>>> Until recently batteries have been inherently safe: unless you did
>>> something stupid they were unlikely to give any trouble. You are now
>>> supporting a type of battery that is inherently unsafe and will catch
>>> fire or explode unless the user takes some positive action.
>>
>> But happens to offer a much higher energy density.
>>
>> It takes a long time to degrade to the point where it can catch fire or
>> explode, and the degradation is entirely detectable.
>>
>>> Even if the user delegates this action to an automated system there is
>>> no guarantee that the action will be taken every time it is needed.
>>
>> And the brakes on your car don't always work, but we do seem to be
>> willing to live with that.
>>
>>> 'Safety' that depends on taking a positive action to prevent a disaster
>>> is not safe at all.
>>
>> But we live with that, when the advantages are proportionate to the risk.
>
> My van has dual hydraulic systems for the footbrake, a mechanical
> handbrake and even gears that could slow it down in an emergency. If I
> park it somewhere, the chance of it crashing into something while I am
> not there to stop it is very small indeed, I don't need to take any
> positive action.
>
> I suspect the number of spontaneous fires of vehicles with lithium
> batteries is far higher in relation to the number on the roads than the
> number of spontaneous runaways and crashes of diesel and petrol
> vehicles.

It isn't - the numbers are quite a bit lower. There have already been
some insurance statistics accumulated and some of them have been posted
here. Electric cars haven't been around for all that long so to some
extent this is comparing relatively new electric cars with a populations
of IC cars which includes some antiquated junk, but electric cars do
seem to be quite a bit safer.

Newspapers don't emphasise this.

> In addition there is the same risk of brake failure on an
> electric vehicle - even more so if it has an electric parking brake
> which is the driver cannot operate quickly in an emergency.

The point was not the efficacy of the brakes but the existence of a risk
which we are willing to tolerate.

--
Bill Sloman, Sydney

On Sat, 13 Apr 2024 18:27:46 -0700, John Larkin
<jjSNIPlarkin@highNONOlandtechnology.com> wrote:

>On Fri, 12 Apr 2024 10:07:59 -0700, John Robertson <jrr@flippers.com>
>wrote:
>
>>On 2024/04/12 9:52 a.m., john larkin wrote:
>>> On Fri, 12 Apr 2024 12:22:00 -0400, bitrex <user@example.net> wrote:
>>>
>>>> On 4/12/2024 10:04 AM, Bill Sloman wrote:
>>>>> On 12/04/2024 9:16 pm, Carlos E.R. wrote:
>>>>>> On 2024-04-12 07:19, Bill Sloman wrote:
>>>>>>> On 9/04/2024 3:03 am, Jeroen Belleman wrote:
>>>>>>>> On 4/8/24 18:35, John Larkin wrote:
>>>>>>>>> https://www.bbc.com/news/uk-england-london-68744317
>>>>>>>>>
>>>>>>>>> It doesn't look like that one was charging.
>>>>>>>>>
>>>>>>>>> Lithium battery fires are a big deal in New York too.
>>>>>>>>>
>>>>>>>>> San Fancisco is swarming with illegal, unlicensed electric scooters,
>>>>>>>>> surfboards, wheelie things, bikes, and motorcycles.
>>
>>As are most cities with access to Amazon/eBay...(no regulations on what
>>people can sell on these platforms)
>>
>>...
>>>> And fretting about the hazards of exploding batteries with 300 million
>>>> guns floating around is pretty schizophrenic. Compared to being injured
>>>> by an exploding bike (or shot by a stranger for that matter) your
>>>> chances of being shot by a police officer are at least the same, or higher.
>>>
>>> About 1300 people were killed by police in the US last year, out of a
>>> population of 333 million, about 4 PPM. Cops rarely shoot polite
>>> law-abiding citizens; don't threaten people, especially cops, with
>>> guns or knives.
>>
>>Here in Canada the average number of people killed by police annually is
>>just under 40 per year since 2011. Out of a population of roughly
>>40,000,000 or 1 PPM in other words.
>>
>>Perhaps our gun laws do make a difference.
>>
>>John :-#)#
>
>The population mix makes a bigger difference. Bad guys will always
>find guns.

Guns don't kill people. People kill people.

On 4/13/24 9:35 AM, John Larkin wrote:
> On Sat, 13 Apr 2024 16:14:07 +0100, liz@poppyrecords.invalid.invalid
.....
>
> And a defect sensor would have to constantly snoop every cell of a
> pack. A typical Tesla might have 7000 cells.
>

Tesla (and every other EV manufacturer) does monitor the voltage of
every individual cell and every cell has its own fusible link in case it
becomes shorted.

kw

On Sun, 14 Apr 2024 10:10:31 -0700, KevinJ93 <kevin_es@whitedigs.com>
wrote:

>On 4/13/24 9:35 AM, John Larkin wrote:
>> On Sat, 13 Apr 2024 16:14:07 +0100, liz@poppyrecords.invalid.invalid
>....
>>
>> And a defect sensor would have to constantly snoop every cell of a
>> pack. A typical Tesla might have 7000 cells.
>>
>
>Tesla (and every other EV manufacturer) does monitor the voltage of
>every individual cell and every cell has its own fusible link in case it
>becomes shorted.
>
>kw

Tesla uses many small cell in parallel, numbers like 74. I wonder how
they could monitor the voltage of each cell.

I assume "becomes shorted" means that the battery terminals are
shorted somehow. The bigger hazard is that a cell will short
internally, and all its paralleled friends will then dump thousands of
amps into it.

Monitoring or fusing won't help a 5-second internal ignition from a
separator failure.

I'm certain that few cheap Chinese bike and scooter batteries have any
sort of safety systems. As they age, they may get more dangerous.

John Larkin <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
> On Sun, 14 Apr 2024 10:10:31 -0700, KevinJ93 <kevin_es@whitedigs.com>
> wrote:
>
>> On 4/13/24 9:35 AM, John Larkin wrote:
>>> On Sat, 13 Apr 2024 16:14:07 +0100, liz@poppyrecords.invalid.invalid
>> ....
>>>
>>> And a defect sensor would have to constantly snoop every cell of a
>>> pack. A typical Tesla might have 7000 cells.
>>>
>>
>> Tesla (and every other EV manufacturer) does monitor the voltage of
>> every individual cell and every cell has its own fusible link in case it
>> becomes shorted.
>>
>> kw
>
> Tesla uses many small cell in parallel, numbers like 74. I wonder how
> they could monitor the voltage of each cell.
>
> I assume "becomes shorted" means that the battery terminals are
> shorted somehow. The bigger hazard is that a cell will short
> internally, and all its paralleled friends will then dump thousands of
> amps into it.
>

Not if there was a fuse in series with each cell

--
piglet

On Sun, 14 Apr 2024 20:38:45 -0000 (UTC), piglet
<erichpwagner@hotmail.com> wrote:

>John Larkin <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
>> On Sun, 14 Apr 2024 10:10:31 -0700, KevinJ93 <kevin_es@whitedigs.com>
>> wrote:
>>
>>> On 4/13/24 9:35 AM, John Larkin wrote:
>>>> On Sat, 13 Apr 2024 16:14:07 +0100, liz@poppyrecords.invalid.invalid
>>> ....
>>>>
>>>> And a defect sensor would have to constantly snoop every cell of a
>>>> pack. A typical Tesla might have 7000 cells.
>>>>
>>>
>>> Tesla (and every other EV manufacturer) does monitor the voltage of
>>> every individual cell and every cell has its own fusible link in case it
>>> becomes shorted.
>>>
>>> kw
>>
>> Tesla uses many small cell in parallel, numbers like 74. I wonder how
>> they could monitor the voltage of each cell.
>>
>> I assume "becomes shorted" means that the battery terminals are
>> shorted somehow. The bigger hazard is that a cell will short
>> internally, and all its paralleled friends will then dump thousands of
>> amps into it.
>>
>
>Not if there was a fuse in series with each cell

The case stated above is "in case it becomes shorted."

If a cell shorts internally, as they tend to do, no monitoring or
fusing will help. Running will help.

I once worked with a fire alarm company in Freehold, New Jersey. A
sign on the wall said

IN CASE OF FIRE

run, yell FIRE

On 4/14/24 1:11 PM, John Larkin wrote:
> On Sun, 14 Apr 2024 10:10:31 -0700, KevinJ93 <kevin_es@whitedigs.com>
> wrote:
>
>> On 4/13/24 9:35 AM, John Larkin wrote:
>>> On Sat, 13 Apr 2024 16:14:07 +0100, liz@poppyrecords.invalid.invalid
>> ....
>>>
>>> And a defect sensor would have to constantly snoop every cell of a
>>> pack. A typical Tesla might have 7000 cells.
>>>
>>
>> Tesla (and every other EV manufacturer) does monitor the voltage of
>> every individual cell and every cell has its own fusible link in case it
>> becomes shorted.
>>
>> kw
>
> Tesla uses many small cell in parallel, numbers like 74. I wonder how
> they could monitor the voltage of each cell.
>

As you say many are in parallel in a module (the actual number varies
with the particular model and revision). The cell voltage of all those
cells are the same so can be measured with a single channel of the BMS.

> I assume "becomes shorted" means that the battery terminals are
> shorted somehow. The bigger hazard is that a cell will short
> internally, and all its paralleled friends will then dump thousands of
> amps into it.

Each cell has its own fusible link so in that case the link for that
specific cell will blow. The maximum current for an individual cell is
in the region of 40-50A.

In some models Tesla has an overall pyrotechnic fuse to disconnect the
pack from the vehicle very rapidly if there is excess current (>1000A or
so).

> Monitoring or fusing won't help a 5-second internal ignition from a
> separator failure.

Each cell is in a steel cylinder that can contain a single cell failure
and minimize the probability of cascade failure. A fully-charged cell
contains about 10-20 Wh of energy.

Some car manufacturers use larger format cells with significantly larger
storage per cell.

> I'm certain that few cheap Chinese bike and scooter batteries have any
> sort of safety systems. As they age, they may get more dangerous.
>
I believe that some of those use pouch cells (similar to those in
cell-phones, tablets and notebook computers). There is less physical
protection against cascade failure in that case.

kw

On Sun, 14 Apr 2024 14:56:43 -0700, KevinJ93 wrote:

> On 4/14/24 1:11 PM, John Larkin wrote:
>> On Sun, 14 Apr 2024 10:10:31 -0700, KevinJ93 <kevin_es@whitedigs.com>
>> wrote:
>>
>>> On 4/13/24 9:35 AM, John Larkin wrote:
>>>> On Sat, 13 Apr 2024 16:14:07 +0100, liz@poppyrecords.invalid.invalid
>>> ....
>>>>
>>>> And a defect sensor would have to constantly snoop every cell of a
>>>> pack. A typical Tesla might have 7000 cells.
>>>>
>>>>
>>> Tesla (and every other EV manufacturer) does monitor the voltage of
>>> every individual cell and every cell has its own fusible link in case
>>> it becomes shorted.
>>>
>>> kw
>>
>> Tesla uses many small cell in parallel, numbers like 74. I wonder how
>> they could monitor the voltage of each cell.
>>
>>
> As you say many are in parallel in a module (the actual number varies
> with the particular model and revision). The cell voltage of all those
> cells are the same so can be measured with a single channel of the BMS.
>
>> I assume "becomes shorted" means that the battery terminals are shorted
>> somehow. The bigger hazard is that a cell will short internally, and
>> all its paralleled friends will then dump thousands of amps into it.
>
> Each cell has its own fusible link so in that case the link for that
> specific cell will blow. The maximum current for an individual cell is
> in the region of 40-50A.
>
> In some models Tesla has an overall pyrotechnic fuse to disconnect the
> pack from the vehicle very rapidly if there is excess current (>1000A or
> so).
>
>> Monitoring or fusing won't help a 5-second internal ignition from a
>> separator failure.
>
> Each cell is in a steel cylinder that can contain a single cell failure
> and minimize the probability of cascade failure. A fully-charged cell
> contains about 10-20 Wh of energy.
>
> Some car manufacturers use larger format cells with significantly larger
> storage per cell.
>
>> I'm certain that few cheap Chinese bike and scooter batteries have any
>> sort of safety systems. As they age, they may get more dangerous.
>>
> I believe that some of those use pouch cells (similar to those in
> cell-phones, tablets and notebook computers). There is less physical
> protection against cascade failure in that case.
>
> kw

Tesla battery assembly and wiring:

<https://circuitdigest.com/article/tesla-model-s-battery-system-an-
engineers-perspective>

BEV fire risk discussion:

https://spectrum.ieee.org/lithium-ion-battery-fires

Relatively few battery fires actually occur in BEVs, more in hybrids and
/way/ more in scooters. Statistics from insurance companies all seem to
agree, BEV fires are less common than combustion engine vehicle fires:

https://www.popsci.com/technology/electric-vehicle-fire-rates-study/

Have any Tesla batteries burst into flame from a separator failure? All
the Tesla battery fires I have heard of were caused by mechanical damage,
a common cause of fossil fuel fires also.

On 15/04/2024 3:09 am, Cursitor Doom wrote:
> On Sat, 13 Apr 2024 18:27:46 -0700, John Larkin <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
>> On Fri, 12 Apr 2024 10:07:59 -0700, John Robertson <jrr@flippers.com wrote:
>>> On 2024/04/12 9:52 a.m., john larkin wrote:
>>>> On Fri, 12 Apr 2024 12:22:00 -0400, bitrex <user@example.net> wrote:
>>>>> On 4/12/2024 10:04 AM, Bill Sloman wrote:
>>>>>> On 12/04/2024 9:16 pm, Carlos E.R. wrote:
>>>>>>> On 2024-04-12 07:19, Bill Sloman wrote:
>>>>>>>> On 9/04/2024 3:03 am, Jeroen Belleman wrote:
>>>>>>>>> On 4/8/24 18:35, John Larkin wrote:

<snip>

>> The population mix makes a bigger difference. Bad guys will always
>> find guns.
>
> Guns don't kill people. People kill people.

This is the NRA mantra.

Guns make it easier for a person to kill more people if that's what the
person chooses to do. Sensible guns control laws tend to keep guns out
of the hands of people who make that choice.

Sydney had such a murderous event on Saturday afternoon - a nut with a
big knife ran around a local shopping center stabbing people. He managed
to kill six people, and he injured nine more including a baby before the
police shot him dead.

If he had had a gun, he would have killed and injured more.

https://www.smh.com.au/national/nsw/bondi-junction-shooting-stabbings-live-updates-police-operation-in-sydney-s-eastern-suburbs-20240413-p5fjku.html

The killer had had mental health issue for quite some time.

--
Bill Sloman, Sydney

On 2024/04/14 10:09 a.m., Cursitor Doom wrote:
> On Sat, 13 Apr 2024 18:27:46 -0700, John Larkin
> <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
>
>> On Fri, 12 Apr 2024 10:07:59 -0700, John Robertson <jrr@flippers.com>
>> wrote:
>>
>>> On 2024/04/12 9:52 a.m., john larkin wrote:
>>>> On Fri, 12 Apr 2024 12:22:00 -0400, bitrex <user@example.net> wrote:
>>>>
>>>>> On 4/12/2024 10:04 AM, Bill Sloman wrote:
>>>>>> On 12/04/2024 9:16 pm, Carlos E.R. wrote:
>>>>>>> On 2024-04-12 07:19, Bill Sloman wrote:
>>>>>>>> On 9/04/2024 3:03 am, Jeroen Belleman wrote:
>>>>>>>>> On 4/8/24 18:35, John Larkin wrote:
>>>>>>>>>> https://www.bbc.com/news/uk-england-london-68744317
>>>>>>>>>>
>>>>>>>>>> It doesn't look like that one was charging.
>>>>>>>>>>
>>>>>>>>>> Lithium battery fires are a big deal in New York too.
>>>>>>>>>>
>>>>>>>>>> San Fancisco is swarming with illegal, unlicensed electric scooters,
>>>>>>>>>> surfboards, wheelie things, bikes, and motorcycles.
>>>
>>> As are most cities with access to Amazon/eBay...(no regulations on what
>>> people can sell on these platforms)
>>>
>>> ...
>>>>> And fretting about the hazards of exploding batteries with 300 million
>>>>> guns floating around is pretty schizophrenic. Compared to being injured
>>>>> by an exploding bike (or shot by a stranger for that matter) your
>>>>> chances of being shot by a police officer are at least the same, or higher.
>>>>
>>>> About 1300 people were killed by police in the US last year, out of a
>>>> population of 333 million, about 4 PPM. Cops rarely shoot polite
>>>> law-abiding citizens; don't threaten people, especially cops, with
>>>> guns or knives.
>>>
>>> Here in Canada the average number of people killed by police annually is
>>> just under 40 per year since 2011. Out of a population of roughly
>>> 40,000,000 or 1 PPM in other words.
>>>
>>> Perhaps our gun laws do make a difference.
>>>
>>> John :-#)#
>>
>> The population mix makes a bigger difference. Bad guys will always
>> find guns.

If there are guns to be easily found.

Make it harder to find guns, and bad guys can't get them easily. Where
it is easier to procure guns, gun violence is increased. Where it is
harder to get guns, fewer people are killed. Gun dealers don't want that
message getting out though.

I don't think the US has ore bad people than anywhere else. People are
people. Bullies who can't get guns readily are easier to stop.
>
> Guns don't kill people. People kill people.

The correct anecdote would be

"Guns don't kill people (all by themselves), people (find it easier) to
kill people (using guns)."

John

On Sun, 14 Apr 2024 22:58:18 -0700, John Robertson <jrr@flippers.com>
wrote:

>On 2024/04/14 10:09 a.m., Cursitor Doom wrote:
>> On Sat, 13 Apr 2024 18:27:46 -0700, John Larkin
>> <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
>>
>>> On Fri, 12 Apr 2024 10:07:59 -0700, John Robertson <jrr@flippers.com>
>>> wrote:
>>>
>>>> On 2024/04/12 9:52 a.m., john larkin wrote:
>>>>> On Fri, 12 Apr 2024 12:22:00 -0400, bitrex <user@example.net> wrote:
>>>>>
>>>>>> On 4/12/2024 10:04 AM, Bill Sloman wrote:
>>>>>>> On 12/04/2024 9:16 pm, Carlos E.R. wrote:
>>>>>>>> On 2024-04-12 07:19, Bill Sloman wrote:
>>>>>>>>> On 9/04/2024 3:03 am, Jeroen Belleman wrote:
>>>>>>>>>> On 4/8/24 18:35, John Larkin wrote:
>>>>>>>>>>> https://www.bbc.com/news/uk-england-london-68744317
>>>>>>>>>>>
>>>>>>>>>>> It doesn't look like that one was charging.
>>>>>>>>>>>
>>>>>>>>>>> Lithium battery fires are a big deal in New York too.
>>>>>>>>>>>
>>>>>>>>>>> San Fancisco is swarming with illegal, unlicensed electric scooters,
>>>>>>>>>>> surfboards, wheelie things, bikes, and motorcycles.
>>>>
>>>> As are most cities with access to Amazon/eBay...(no regulations on what
>>>> people can sell on these platforms)
>>>>
>>>> ...
>>>>>> And fretting about the hazards of exploding batteries with 300 million
>>>>>> guns floating around is pretty schizophrenic. Compared to being injured
>>>>>> by an exploding bike (or shot by a stranger for that matter) your
>>>>>> chances of being shot by a police officer are at least the same, or higher.
>>>>>
>>>>> About 1300 people were killed by police in the US last year, out of a
>>>>> population of 333 million, about 4 PPM. Cops rarely shoot polite
>>>>> law-abiding citizens; don't threaten people, especially cops, with
>>>>> guns or knives.
>>>>
>>>> Here in Canada the average number of people killed by police annually is
>>>> just under 40 per year since 2011. Out of a population of roughly
>>>> 40,000,000 or 1 PPM in other words.
>>>>
>>>> Perhaps our gun laws do make a difference.
>>>>
>>>> John :-#)#
>>>
>>> The population mix makes a bigger difference. Bad guys will always
>>> find guns.
>
>If there are guns to be easily found.
>
>Make it harder to find guns, and bad guys can't get them easily. Where
>it is easier to procure guns, gun violence is increased. Where it is
>harder to get guns, fewer people are killed. Gun dealers don't want that
>message getting out though.
>
>I don't think the US has ore bad people than anywhere else. People are
>people. Bullies who can't get guns readily are easier to stop.
>>
>> Guns don't kill people. People kill people.
>
>The correct anecdote would be
>
>"Guns don't kill people (all by themselves), people (find it easier) to
>kill people (using guns)."

That's too verbose, it'll never catch on.

On 15/04/2024 9:18 pm, Cursitor Doom wrote:
> On Sun, 14 Apr 2024 22:58:18 -0700, John Robertson <jrr@flippers.com>
> wrote:
>
>> On 2024/04/14 10:09 a.m., Cursitor Doom wrote:
>>> On Sat, 13 Apr 2024 18:27:46 -0700, John Larkin
>>> <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
>>>
>>>> On Fri, 12 Apr 2024 10:07:59 -0700, John Robertson <jrr@flippers.com>
>>>> wrote:
>>>>
>>>>> On 2024/04/12 9:52 a.m., john larkin wrote:
>>>>>> On Fri, 12 Apr 2024 12:22:00 -0400, bitrex <user@example.net> wrote:
>>>>>>
>>>>>>> On 4/12/2024 10:04 AM, Bill Sloman wrote:
>>>>>>>> On 12/04/2024 9:16 pm, Carlos E.R. wrote:
>>>>>>>>> On 2024-04-12 07:19, Bill Sloman wrote:
>>>>>>>>>> On 9/04/2024 3:03 am, Jeroen Belleman wrote:
>>>>>>>>>>> On 4/8/24 18:35, John Larkin wrote:
>>>>>>>>>>>> https://www.bbc.com/news/uk-england-london-68744317
>>>>>>>>>>>>
>>>>>>>>>>>> It doesn't look like that one was charging.
>>>>>>>>>>>>
>>>>>>>>>>>> Lithium battery fires are a big deal in New York too.
>>>>>>>>>>>>
>>>>>>>>>>>> San Fancisco is swarming with illegal, unlicensed electric scooters,
>>>>>>>>>>>> surfboards, wheelie things, bikes, and motorcycles.
>>>>>
>>>>> As are most cities with access to Amazon/eBay...(no regulations on what
>>>>> people can sell on these platforms)
>>>>>
>>>>> ...
>>>>>>> And fretting about the hazards of exploding batteries with 300 million
>>>>>>> guns floating around is pretty schizophrenic. Compared to being injured
>>>>>>> by an exploding bike (or shot by a stranger for that matter) your
>>>>>>> chances of being shot by a police officer are at least the same, or higher.
>>>>>>
>>>>>> About 1300 people were killed by police in the US last year, out of a
>>>>>> population of 333 million, about 4 PPM. Cops rarely shoot polite
>>>>>> law-abiding citizens; don't threaten people, especially cops, with
>>>>>> guns or knives.
>>>>>
>>>>> Here in Canada the average number of people killed by police annually is
>>>>> just under 40 per year since 2011. Out of a population of roughly
>>>>> 40,000,000 or 1 PPM in other words.
>>>>>
>>>>> Perhaps our gun laws do make a difference.
>>>>>
>>>>> John :-#)#
>>>>
>>>> The population mix makes a bigger difference. Bad guys will always
>>>> find guns.
>>
>> If there are guns to be easily found.
>>
>> Make it harder to find guns, and bad guys can't get them easily. Where
>> it is easier to procure guns, gun violence is increased. Where it is
>> harder to get guns, fewer people are killed. Gun dealers don't want that
>> message getting out though.
>>
>> I don't think the US has ore bad people than anywhere else. People are
>> people. Bullies who can't get guns readily are easier to stop.
>>>
>>> Guns don't kill people. People kill people.
>>
>> The correct anecdote would be
>>
>> "Guns don't kill people (all by themselves), people (find it easier) to
>> kill people (using guns)."
>
> That's too verbose, it'll never catch on.

It's not the verbosity that's the problem, it's the fact that it sends
different message, and a message that's inconvenient to people who make
money out of making and selling guns, and want to make more money out of
selling even more of them.

That sort of reasoning doesn't appeal to you - you need the lunatic
element to get your turn-on.

--
Bill Sloman, Sydney