<whitequark>
yeah it's like... i foresee being in US, EU and HK a lot going forward and my current phone only had LTE in EU and EDGE in US and nothing in HK
<whitequark>
it was a deeply unpleasant experience
<whitequark>
to be fair, there are like twenty LTE bands and they're all over and it's an extreme clusterfuck
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<wpwrak>
yes, UTMS is bad, LTE worse. i love my GSM ;-)
<whitequark>
you do realize in many places it's not deployed anymore, right?
<whitequark>
HK has data over neither UMTS nor GSM
<whitequark>
US doesn't have data over GSM
<wpwrak>
but telephony ?
<whitequark>
telephony, yes, I could not possibly care less about calls. I don't call people
<wpwrak>
ah :)
<whitequark>
for several reasons, including: many of my peers don't disclose their cellular number bc of very practical privacy concerns
<wpwrak>
for data, i use WLAN. data over telephony is usually economical suicide.
<whitequark>
if the data you transmit is mostly text...
<wpwrak>
ah yes, reveal thy number and there will be a drone homing in on you soon ...
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<DocScrutinizer05>
WOW, never seen before: https://www.google.com/url?q=http://home.jeita.or.jp/page_file/20110517171451_cub9MvYFEh.pdf&sa=U&ved=0CBQQFjAAahUKEwjn1rOM5vHHAhWCShQKHbZ-BY4&usg=AFQjCNHB1q1Dueo14Cy3pBAGoQUb34Vuzg
<DocScrutinizer05>
LiIon generic safety requirements (also for dis/charging) form Japan $entity
<DocScrutinizer05>
seems sorta authoritative
<DocScrutinizer05>
krhrhrhr >> To prevent hot electrolyte steam emitted from a gas-releasing vent to be staying in the battery enclosure and to catch fire, it is imperative that an electrolyte steam outlet is prepared. Such outlet should be positioned to allow the steam emitted to be directed away from the user.<<
<DocScrutinizer05>
ROTFL @ >> If the circuit board is provided with a storage device storing the operating status of the battery, arrange the board so that the storage device is located away from the cell. This is to ensure that the stored data is protected from the influence by the heat generated in the event of a battery fault.<<
<DocScrutinizer05>
as if anybody would be interested in the stored status info of an exploded battery ;-P
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<whitequark>
actually, that would be useful when you do root cause analysis
<DocScrutinizer05>
hmm, mildly
<DocScrutinizer05>
you can tell charging status by strength of explosion ;-P
<DocScrutinizer05>
anyway I don't see how this is a mandatory design requirement for all batteries
<DocScrutinizer05>
on the same level of importance like first quote up there
<DocScrutinizer05>
about electrolyte steam emitted
<DocScrutinizer05>
they have a few more such quite reasonable requirements like thermal isolation between cells of battery, etc. I can't see how this nonsense to protect the status storage chip from overheating in case of fatal battery failure helps preventing the battery to fail
<DocScrutinizer05>
or contributes to the security of that battery at large
<whitequark>
I am quite sure it is there to help doing RCA
<whitequark>
do batteries fail early in life? what was the min/max temperature? etc
<whitequark>
and these are just parameters any random charge controller will record, not even one specifically designed to be useful for RCA
<DocScrutinizer05>
how's a battery supposed to even fail? all the other requirements are made to ensure it doesn't, in a way that would destroy anything
<DocScrutinizer05>
it's a pretty silly requirement anyway
<whitequark>
left out in the sun? puncture?
<DocScrutinizer05>
I won't send in such battery remnants for forensics to the battery manufacturer
<DocScrutinizer05>
and battery manuf isn't interested in doing any forensics on them anyway
<whitequark>
that's assuming you already know the cause
<whitequark>
temp stats will allow to distinguish between those two
<DocScrutinizer05>
ohmy, how's that an item for a generic battery saftety requirements whitepaper?
<whitequark>
I think anything that can fail and seriously injure someone /must/ be amenable to RCA of failure
<DocScrutinizer05>
aha! so they should have made that chip mandatory
<whitequark>
that would make sense, yes
<DocScrutinizer05>
in everything, not just batteries
<whitequark>
well, a PCB failing won't lead to that
<whitequark>
your shitty phone just stops to work. no big deal
<DocScrutinizer05>
aha, even when that PCB is for example controlling your car engine or steering?
<whitequark>
no, sure not, cars fall into the same category as batteries
<DocScrutinizer05>
yet nobody ever asked for such recording chips in the engine controller
<whitequark>
should've said "well, most PCBs failing won't lead to that"
<DocScrutinizer05>
neither in the car battery which nowadays also often is LiIon
<whitequark>
huh? doesn't a LiIon car battery fall under the exact whitepaper you're citing?
<whitequark>
but yes, I would definitely expect a car /battery/ have such a facility, regardless of chemistry, and a car in general
<DocScrutinizer05>
yes, however it usually doesn't have any such status recording chip I'd know of
<whitequark>
a car already has a shitton of sensors, and definitely you should log everything into a 'blackbox'
<DocScrutinizer05>
it's supposed to work and nobody even cares about charging state
<whitequark>
I know for a fact some cars have pretty advanced blackboxes
<whitequark>
that include things like hydraulic pressure, steering position, engine stats and yes battery charge
<DocScrutinizer05>
tzz, never seen a car battery with more than 2 poles
<whitequark>
oh, you mean a lead-acid battery in a non-electric car
<DocScrutinizer05>
so yes, your car blackbox might record the voltage of battery
<whitequark>
those don't really fail hazardously, do they? except in a collision or something, where all bets are loose
<DocScrutinizer05>
exactly, they are supposed to work and nobody cares if it's lead acid or LiIon
<whitequark>
well no there is a large difference
<whitequark>
LiIon supports a runaway reaction that leads to explosion, lead acid doesn't
<whitequark>
LiFePO4 also doesn't and you know what? there is no limitation on amount of LiFePO4 batteries you can take or ship in an aircraft
<whitequark>
exactly because of that
<DocScrutinizer05>
yes, and still no external monitoring and most likely no internal monitoring and recording either. They simply are supposed to work and never ever fail
<whitequark>
sure
<whitequark>
that's consistent with everything I said above I think?
<DocScrutinizer05>
well, when you mix stuff then yes. I talked about LiIon, not LiFePo
<whitequark>
then let me summarize: LiFePO4, lead acid don't fail hazardously, no monitoring. LiIon does, has to have monitoring
<whitequark>
seems right to me?
<DocScrutinizer05>
my point stands: it's silly to require a disaster-hardened recorder chip without making that recorder chip a mandatory feature to start with
<whitequark>
oh, yes
<whitequark>
it doesn't?
<DocScrutinizer05>
>>**If the circuit board is provided** with a storage device storing the operating status of the battery, arrange the board so that the storage device is located away from the cell.<<
<whitequark>
oh
<whitequark>
well that's just... bullshit
<DocScrutinizer05>
and that in a generic wqhitepaper about battery security requirements
<DocScrutinizer05>
exactly, just bullshit
<DocScrutinizer05>
some dude had a momentary hiccup
<DocScrutinizer05>
or rather cerbral brownout
<whitequark>
hehe
<DocScrutinizer05>
it's a 'nice to have' at best, at the discretion of the particular battery manuf
<DocScrutinizer05>
"dear designer, when you already add a recorder to your battery, consider added benefit fron placing it in a position where it will survive disasters. You'll love the forensic options it offers"
<DocScrutinizer05>
that's stuff for an EE 101 book, not for a generic semi-official whitepaper about security requerements
<DocScrutinizer05>
or maybe they meant "battery failure" == simple overtemperature, where the battery could recover from. And you wouldn't want such "failure" to damage the status recorder and that causing secondary induced disaster
<whitequark>
hmmm
<whitequark>
I'd imagine anything that kills the IC or even the flex cable will destroy the battery very well
<whitequark>
it's well over 100 and even 150
<DocScrutinizer05>
however that's already covered by their other policies, like "no single point of failure"
<whitequark>
wait, what
<whitequark>
how the fuck does that work
<DocScrutinizer05>
yep
<whitequark>
I'm not sure I have ever seen a battery satisfying that design
<whitequark>
requirement
<whitequark>
maybe those larger car ones, I dunno, definitely not in small electronics
<DocScrutinizer05>
no single fault fail?
<whitequark>
yeah
<whitequark>
oh, or do they mean like
<DocScrutinizer05>
all devices are supposed to have at least 2 independant security means
<whitequark>
"you need both a temperature sensor AND an overcurrent sensor failure"?
<DocScrutinizer05>
no, they mean "when FET in electronic security fails, there still needs to be a blowfuse to kick in"
<whitequark>
ah alright
<DocScrutinizer05>
no single point of failure scenarios
<DocScrutinizer05>
that can't get handled by another subsystem
<DocScrutinizer05>
in the usual smartphone you have at least 3 independant security mechanisms
<DocScrutinizer05>
the standard high level charger, plus a electrinics and a PTC or whatever in the battery itself
<DocScrutinizer05>
often the phone also has an additional fuse in batery rail
<DocScrutinizer05>
cheap chinese chargers rely entirely on the electronics in battery to avoid overcharging
<whitequark>
yeah I've seen those
<DocScrutinizer05>
which is a damn poor design
<whitequark>
one of them was USB5V connected via a diode
<DocScrutinizer05>
great! ;-P
<DocScrutinizer05>
I've seen one charger that literally consisted of a plastic case, two springs for battery, two steel poles for mains jack, two capacitors and a Graetz bridge
<DocScrutinizer05>
*nothing else*
<whitequark>
the capacitors form a divider?
<DocScrutinizer05>
series impedance for both mains poles
<whitequark>
SERIES?!
<DocScrutinizer05>
basically you had Live voltage on both battery contacts, mitigated by a series 1uF or something
<whitequark>
yeah that's so fucked up
<DocScrutinizer05>
I really thought that must be a bad joke or something
<whitequark>
that's depressing
<DocScrutinizer05>
for such "charger" any battery internal electronics will fail epically since they can't cope with dunno 110V or even 230V
<DocScrutinizer05>
I guess that crap must have been 19 pence on some chinese "whatever you search for, here you'll find it" shop or market
<DocScrutinizer05>
and the guy who designed and marketed that crap maybe killed a few dozen people with it, but for sure made a million and had no problems whatsoever
<DocScrutinizer05>
I bet same shop sold a plug with cable with two blank wire ends as a water heater
<whitequark>
you can put an unsafe razor blade between those. some people legit make heaters like that
<DocScrutinizer05>
"to speed up cooking, add some salt to water"
<whitequark>
now it's sharp, hot AND under voltage
<DocScrutinizer05>
called "Moped" in german jail
<whitequark>
why?
<DocScrutinizer05>
dunno
<DocScrutinizer05>
tobacco is caled "Koffer"
<DocScrutinizer05>
seems they have a special language in jail
<whitequark>
yeah, jail jargon
<whitequark>
or more like prison
<whitequark>
does 'normal' german have a lot of loanwords from prison jargon?
<DocScrutinizer05>
hmm, I probably can't know, but I also don't know of many
<whitequark>
russian sure does. not surprising given the amount of people who were in camps. 1/3 of population at some point, I think
<DocScrutinizer05>
maybe formerly "Heierman" for a 5 DM coin
<whitequark>
and a good deal of those loanwords are now just everyday words
<DocScrutinizer05>
in certain social groups it's naturally a lot more
<whitequark>
I mean like middle class
<DocScrutinizer05>
those groups that form outside of prison but all the members are highly likely to end in prison eventually
<DocScrutinizer05>
I just wonder where the heck they get razorblades in prison
<DocScrutinizer05>
sounds like the last thing I'd make available in prison
<whitequark>
smuggle inside by using body color band-aid to tape it to your body?
<DocScrutinizer05>
dunno
<whitequark>
well, that's the apocryphal story
<whitequark>
things get smuggled into prisons all the time
<DocScrutinizer05>
never been in real prison, only several weeks in "Untersuchungshaft" when they arrested hundreds of people who happened to be wrong place wrong time
<whitequark>
detention
<whitequark>
yea
<DocScrutinizer05>
I was evidently the one person who arrived there late and so wasn't involved in the reason of mass detention. And I was the last to go free since what I said had happened was "impossible to have happened" according to police :-S
<whitequark>
ugh
<DocScrutinizer05>
so everybody who said "yes, I joined that demo but I didn't throw stones" went free. While I said "I wasn't on the demo and enetered the building when it was already surrounded by police" had no plausible alibi
<DocScrutinizer05>
shit happens ;-)
<whitequark>
lesson: don't tell truth to authority, tell them what they want to hear :p
<DocScrutinizer05>
(lesson) yes, usually that works. In this particular context however I knew of only one thing they wanted to hear: "Yes, I'm a terrorist"
<DocScrutinizer05>
I think they paid me 5DM per day of that 4 weeks illegal detention, after a year and some
<whitequark>
4 weeks! wtf
<DocScrutinizer05>
toldya, I was the last to go free
<DocScrutinizer05>
except those few they actually knew were throwing stones
<DocScrutinizer05>
anyway since then I have my very own take on politics and state
<DocScrutinizer05>
and a somewhat fraught relation to police
<DocScrutinizer05>
not like this came out of thin air, situation and (political) mood been similar before and after the "detention of 141", and I didn't exactly love police before that already