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Re: Li-Polymer Batteries

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mike wrote on 10/17/2017 3:07 PM:
> On 10/17/2017 3:33 AM, rickman wrote:
>> Jan Panteltje wrote on 10/17/2017 6:26 AM:
>>> On a sunny day (Tue, 17 Oct 2017 06:18:09 -0400) it happened rickman
>>> <gnuarm@gmail.com> wrote in <os4lda$4hi$1@dont-email.me>:
>>>
>>>> Jan Panteltje wrote on 10/17/2017 5:47 AM:
>>>>> On a sunny day (Tue, 17 Oct 2017 05:21:15 -0400) it happened rickman
>>>>> <gnuarm@gmail.com> wrote in <os4i2d$cgp$1@dont-email.me>:
>>>>>
>>>>>> Jan Panteltje wrote on 10/17/2017 4:13 AM:
>>>>>>> On a sunny day (Tue, 17 Oct 2017 01:30:45 -0400) it happened rickman
>>>>>>> <gnuarm@gmail.com> wrote in <os44i7$p0f$1@dont-email.me>:
>>>>>>>
>>>>>>>> rickman wrote on 10/16/2017 10:16 AM:
>>>>>>>>> I'm looking at buying these batteries for a test project and
>>>>>>>>> they ask the
>>>>>>>>> buyer to choose between battery types 357090 & 357095.  I can't
>>>>>>>>> find any
>>>>>>>>> references anywhere that describe what these model numbers
>>>>>>>>> mean.  Anyone know?
>>>>>>>>>
>>>>>>>>> http://www.ebay.com/itm/201761814378
>>>>>>>
>>>>>>> It has build in chips to protect it, very unlikely to cath fire if
>>>>>>> you use a decent charger chip.
>>>>>>
>>>>>> "Very unlikely" is fine when it is sitting on your desk.  If that
>>>>>> happens
>>>>>> you get an appropriate fire extinguisher and put it out or at least
>>>>>> let it
>>>>>> burn and put out anything else it has ignited.  If you are in a
>>>>>> vehicle
>>>>>> where you have no means of escaping and no way to deal with the
>>>>>> fire, you
>>>>>> are SOL.  "Very unlikely" isn't good enough for me.
>>>>>
>>>>> Na, wrap your nuclear plants in ..
>>>>>
>>>>>
>>>>>> Also, I'm not convinced all of these units have protection.  The
>>>>>> two model
>>>>>> numbers would seem to indicate one is 5 mm longer than the other.
>>>>>> I expect
>>>>>> this is exactly the size of the protection board, so one might have
>>>>>> protection and the other might not.  It is not all that unusual for
>>>>>> an eBay
>>>>>> listing to contain errors and complete lies^H^H^H^H^H alternate facts.
>>>>>
>>>>> True, I only looked at the link, you can see the protection board,
>>>>> I have some like that, but only 1000 mAh, marked 'Varta'.
>>>>> From China nevertheless.
>>>>>
>>>>> I have some without protection board too...more RC type single cell
>>>>> lipos.
>>>>> And then I have the 3 cell ones, 30C ... no protection either.
>>>>> Danger all around me,
>>>>> Oh and the box with LiIon super powerfull forgot how many C.
>>>>>
>>>>> Gotta run :-)
>>>>>
>>>>> Think about it, you find lipos everywhere, even in those blutooth
>>>>> earplugs /
>>>>> headsets for your cellphone, and happily plug it in your ear and
>>>>> wear it on your head.
>>>>> Cars have gasoline, bad things can happen...
>>>>> There is a mad dog president in control of the button, I would worry
>>>>> about that first.
>>>>> Probabilities.
>>>>
>>>> I seem to recall a number of professional designs from companies who
>>>> have
>>>> much reputation to loose which burst into flames.
>>>
>>> Was it not Liion?
>>>
>>>
>>>>
>>>> So no, I don't have tons of confidence in Lithium batteries to the
>>>> extent
>>>> that I want to strap one on my kayak with no physical protection
>>>> against the
>>>> boat catching on fire.
>>>
>>> Well just roll.
>>
>> I seem to recall Lithium doesn't do so well in contact with water.
>>
> Interesting to see how far people will go to ignore the total system
> and focus on one ill-conceived component.
> The devil is in the details, and we have few.

Not sure what you mean about ignoring the "system"?


> Do the math.
> How much energy is released in a battery fire?

A lithium batter will release a *lot* more heat than just what is stored in 
the battery.  Even discharged lithium batteries have to be stored safely.


> If you insulate it, how hot will it get inside, since you've
> guaranteed thermal runaway?

Don't care, the concern is to prevent the China syndrome where the battery 
burns its case and melts though my boat.  High density polyethylene won't 
stand up to a lithium fire, or any other type of fire for that matter.


> How much energy is released as heat if you discharge the battery
> at maximum current allowed by  your current limit strategy?
> What does that do to the cell temperature if you insulate it?

The unit won't be drawing the maximum current.  There will be protection to 
prevent this.  The load will be relatively light compared to the C value. 
I'm interested in a long discharge time.


> How often are you gonna use this kayak device?
> Can you not throw it overboard if it catches fire?

Not very easily.  It will be securely affixed to the bow of a 17 foot kayak 
with me in the middle.  My arms aren't 8 foot long.


> I submit that the release mechanism is far more likely
> to jamb than the battery is to catch fire. ;-)

A great reason to prevent a fire from becoming catastrophic.


> Given your paranoia, might a NiMH or Alkaline AA cell pack
> be more cost effective and weigh less and take up less space
> than your protection vault and fire suppression apparatus and floating
> burn unit to treat the injured?  Maybe you should have two burn
> units just in case one of the doctors has a heart attack.

That would be a good idea, but NiMH cells don't have the density.  But that 
might not be a significant issue.  But the circuits to use NiMH in a device 
like this aren't so common.


> I surmise that there are some devices sold on EBAY that are made
> from tested/fully compliant components and do what they say.
> Problem is that you can't tell which.
>
> Battery protection built into the battery won't solve your problem.
> It's there as a backup to your own carefully crafted redundant
> battery management system.  I'm not saying you shouldn't have it.
> I'm saying that you shouldn't rely on it.

Yes, and the battery charger/step up circuit also incorporates protection.


> The good news is that you are very much more likely to drown
> than to catch fire.

I'd hate to hear the bad news.

-- 

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998

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Thread

Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-16 10:16 -0400
  Re: Li-Polymer Batteries Mark Storkamp <mstorkamp@yahoo.com> - 2017-10-16 12:47 -0500
    Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-16 20:49 -0400
  Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 01:30 -0400
    Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 02:28 -0400
    Re: Li-Polymer Batteries Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-17 08:13 +0000
      Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 05:21 -0400
        Re: Li-Polymer Batteries Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-17 09:47 +0000
          Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 06:18 -0400
            Re: Li-Polymer Batteries Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-17 10:26 +0000
              Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 06:33 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-17 15:31 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 16:52 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-18 07:12 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-18 04:58 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-18 09:29 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 16:53 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-18 07:12 +0000
                Re: Li-Polymer Batteries mike <ham789@netzero.net> - 2017-10-17 12:07 -0700
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 17:19 -0400
                Re: Li-Polymer Batteries mike <ham789@netzero.net> - 2017-10-17 20:03 -0700
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 23:36 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-18 17:49 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-18 16:42 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-19 09:11 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-19 10:53 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-19 15:22 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-19 12:18 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-19 16:47 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-19 18:34 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-20 07:48 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-20 04:56 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-20 09:38 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-20 12:47 -0400
                Re: Li-Polymer Batteries Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-20 17:00 +0000
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-20 13:45 -0400
                Re: Li-Polymer Batteries krw@notreal.com - 2017-10-20 20:05 -0400
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-20 22:54 -0400
                Re: Li-Polymer Batteries krw@notreal.com - 2017-10-20 23:03 -0400
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-20 23:23 -0400
                Re: Li-Polymer Batteries krw@notreal.com - 2017-10-21 10:48 -0400
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-21 14:53 -0400
                Re: Li-Polymer Batteries krw@notreal.com - 2017-10-21 19:49 -0400
                Re: Li-Polymer Batteries Jasen Betts <jasen@xnet.co.nz> - 2017-10-27 22:47 +0000
                Re: Li-Polymer Batteries krw@notreal.com - 2017-10-27 22:25 -0400
                Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-19 12:51 -0400
            Re: Li-Polymer Batteries Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-10-17 21:05 +0100
    Re: Li-Polymer Batteries TTman <kraken.sankey@gmail.com> - 2017-10-17 16:02 +0100
      Re: Li-Polymer Batteries rickman <gnuarm@gmail.com> - 2017-10-17 17:37 -0400

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