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Re: Replace Li Ion battery

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krw@notreal.com wrote...
> mike <ham789@netzero.net> wrote:
>> Andy wrote:
>>> mike wrote:
>>>> On 12/26/2017 5:31 AM, Winfield Hill wrote:
>>>>> mike wrote...
>>>>>> Andy wrote:
>>>>>>> I want to replace a LiIon battery with a high
>>>>>>> capacity one.  The old one has a third yellow wire.
>>>>>>> What is it for ?
>>>>>>
>>>>>> If that's the best you can do at specificity,
>>>>>> best not risk setting yourself on fire.
>>>>>
>>>>>    Now, now.  Many single-cell Lithium battery
>>>>>    packs include a thermistor to help prevent
>>>>>    overcharging, and dangerous overheating.
>>>>>    10k at 25 deg C is a common value.
>>>>>
>>>>>    I'd imagine
>>>>
>>>> Those two words suggest that YOU shouldn't be playing
>>>> with lithium batteries either!  Be Safe.
>>>> You may not be the one injured when it catches fire.
>>>>
>>>> that a big battery, replacing a
>>>>>    small one, would experience reduced stress,
>>>>>    because its charge / discharge rate would
>>>>>    be lower.  You do want thermal protection,
>>>>>    be sure to use one with the same themistor.
>>>
>>> Looks like he is safe to me.
>>>
>>> Andy
>>>
>> Sure he is.
>> People who give random DANGEROUS advice in response to
>> a question you haven't even asked don't have to worry
>> about their safety...or yours.
>>
>> To recap the thread...
>> _____________________________
>> I am replacing a small bomb with a big bomb.
>> What's the yellow wire for?
>>
>> I 'imagine' you should use a thermistor.
>> ___________________________
>
> I don't believe you've given a reasonable synopsis.
> Exactly what did Winfield (actually) *write* that
> you disagree with?
>
>> Am I the only one concerned that there is zero
>> information about the bomb or its environment?
>> Or that the bomb that you bought on the internet
>> has the same generic label, but may have radically
>> different characteristics that may or may not lead
>> to surprise detonation?
>
> But you object to Winfield's post.  His statement
> sounded correct to me, though perhaps not a full answer.
>
>> Do not fuck with lithium batteries unless you know
>> EXACTLY the specs of both cells and intimate
>> details of the charge/discharge cycle.
>> If you knew that, you wouldn't have asked about
>> the yellow wire.
>
> What does that have with Win's answer?
>
>> This thread contains ZERO information beyond
>> the color of the wire.
>>
>> Be safe.  Don't do it, or get a LOT more informed
>> about exactly what you're doing.  You can't do that
>> if your question isn't more specific than wire color.
>>
>> Life is a series of calculations of the risk/reward
>> ratios of your actions.
>> Say there's a 99% chance that you'll be ok with your project...
>> and 1% chance that you'll burn your house down, or that your
>> kid will have an eye put out when it explodes.
>> Do you like that risk/reward ratio?
>> I sure don't!
>
> What does anything above have to do with what Win actually wrote?

 Whoa, firestorm!  It's time for me to step in and
 add to my remarks.  First, I specified an answer
 for a single-cell battery, the most common form.

 My comments are incomplete and not relevant for a
 multi-cell battery, as some of the thread seems
 to assume. (I agree that modifying such a battery
 is a serious engineering exercise.)

 We can assume the single cell charging system in
 question is safe, having appropriate voltage and
 current-limiting features, and is equipped with a
 cell temperature sensor (the O.P. will verify this
 using an ohm-meter on his existing cell).  In such
 a case I think it's safe to move to a larger cell,
 incorporating the same range thermistor.  Naturally,
 we assume our O.P. has relevant electronics skills.


-- 
 Thanks,
    - Win

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Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-25 12:36 -0800
  Re: Replace Li Ion battery mike <ham789@netzero.net> - 2017-12-25 20:55 -0800
    Re: Replace Li Ion battery Winfield Hill <hill@rowland.harvard.edu> - 2017-12-26 05:31 -0800
      Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-26 12:47 -0800
        Re: Replace Li Ion battery Jeff Liebermann <jeffl@cruzio.com> - 2017-12-27 08:08 -0800
      Re: Replace Li Ion battery mike <ham789@netzero.net> - 2017-12-26 15:39 -0800
        Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-26 16:27 -0800
          Re: Replace Li Ion battery mike <ham789@netzero.net> - 2017-12-26 20:20 -0800
            Re: Replace Li Ion battery krw@notreal.com - 2017-12-26 23:44 -0500
              Re: Replace Li Ion battery Winfield Hill <hill@rowland.harvard.edu> - 2017-12-27 05:17 -0800
                Re: Replace Li Ion battery mike <ham789@netzero.net> - 2017-12-27 12:59 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-27 19:51 -0800
                Re: Replace Li Ion battery Jeff Liebermann <jeffl@cruzio.com> - 2017-12-27 21:20 -0800
                Re: Replace Li Ion battery Jeff Liebermann <jeffl@cruzio.com> - 2017-12-27 21:35 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-28 08:41 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-28 08:45 -0800
                Re: Replace Li Ion battery Jeff Liebermann <jeffl@cruzio.com> - 2017-12-28 20:24 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-28 20:30 -0800
                Re: Replace Li Ion battery mike <ham789@netzero.net> - 2017-12-29 03:39 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-29 07:04 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-29 11:00 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-28 06:51 -0800
                Re: Replace Li Ion battery mike <ham789@netzero.net> - 2017-12-27 22:26 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-28 08:34 -0800
                Re: Replace Li Ion battery mike <ham789@netzero.net> - 2017-12-28 10:50 -0800
                Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-28 11:52 -0800
                Re: Replace Li Ion battery John S <Sophi.2@invalid.org> - 2017-12-27 23:02 -0600
            Re: Replace Li Ion battery Andy <andrewkennedy775@gmail.com> - 2017-12-26 21:17 -0800

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