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Re: Should I completely discharge my laptop battery?

From mike <ham789@netzero.net>
Newsgroups comp.sys.laptops
Subject Re: Should I completely discharge my laptop battery?
Date 2015-02-07 21:02 -0800
Organization A noiseless patient Spider
Message-ID <mb6qkn$6g4$1@dont-email.me> (permalink)
References (17 earlier) <m8q115$emf$1@dont-email.me> <m8q9et$q8d$1@dont-email.me> <m91koa$og2$1@dont-email.me> <m91rtt$fp8$1@dont-email.me> <mb6dre$9gg$1@dont-email.me>

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On 2/7/2015 5:24 PM, ~misfit~ wrote:
> Once upon a time on usenet mike wrote:
>> On 1/12/2015 3:18 PM, ~misfit~ wrote:
>>> Once upon a time on usenet mike wrote:
>>> [total snip]
>>>> Are we having fun yet?
>>>
>>> Thanks Mike. I've copied that to notepad and saved it for when I
>>> have a bit of time to play with.
>>>
>>> I have a couple of these too
>>> http://www.dx.com/p/mp1405-5v-1a-lithium-battery-charging-board-blue-black-219454#.VLRT1MlZqUc
>>> and used one for re-powering a mini rotary tool I got cheap that
>>> used 3x small NiCad cells in shrink-wrap, the total size of which
>>> was similar to a single 18650 but had little 'power' and didn't hold
>>> much charge. I bought a new solder-tab Panasonic cell for that job
>>> as I didn't know how good my slavaged cells were and it's hard to
>>> open up the modded tool.... However it doesn't seem to like running a
>>> motor from the 'out' pads
>>> - maybe it's something to do with the brushes and how it works? I
>>> tried three of these PCBs for the job and they all didn't work
>>> right. In the end I had to wire a small momentary contact switch
>>> between the B+ and OUT+ pads to start the motor. Once it's started
>>> it runs fine from the 'OUT' contacts. <shrug> As you can probably tell I
>>> only have basic knowledge (but try hard
>>> to not take risks - I'm very aware of the inherant dangers with
>>> Li-Ion tech and the potential for 'thermal runaway').
>>>
>>> Cheers,
>>>
>> The website was translated into ChEnglish and doesn't make a lot of
>> sense, but if I were to guess...
>>
>> How are you switching the power?
>>
>> If you're switching between the battery and the board,
>> that may be your problem.  Sounds like the board has to be powered
>> up continuously.  I'd measure the drain from the battery in the
>> off state.  May be inconsequential...maybe not.
>>
>> If you're switching between the board and the motor, the turn-on
>> transient from the motor may exceed the 3A current limit.  Maybe a
>> big cap across the out pads will help.
>
> Mike, quick question as I'm going to use another of these modules for
> controlled discharge of Li-Ion cells using a motor as a load... What value
> do you mean when you say 'a big cap'?
>
> Cheers,
>
That's not a simple question.  Motor load is complex. I have no idea
how the control board works.
The spec alludes to a 3 amp protection limit.  If your motor starting
current exceeds 3A, you need to limit that somehow.  A cap can help,
but it might take a very big one.  I'd start with 100uF and experiment 
from there.  But a cap won't help for a constant load like locked rotor.

The board says 3A Protection.  It's designed for a Maximum of 1A load.
You can be sure if it would survive much over that, the spec would be 
higher.  Monitor the FET temperature to see if it will melt off the board.

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Thread

Should I completely discharge my laptop battery? andymhancock@gmail.com - 2014-12-30 11:53 -0800
  Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2014-12-31 13:35 +1300
    Re: Should I completely discharge my laptop battery? andymhancock@gmail.com - 2014-12-31 11:06 -0800
      Re: Should I completely discharge my laptop battery? andymhancock@gmail.com - 2014-12-31 11:54 -0800
        Re: Should I completely discharge my laptop battery? andymhancock@gmail.com - 2015-01-01 15:13 -0800
      Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-01 12:29 +1300
    Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2014-12-31 12:05 -0800
      Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-01 12:55 +1300
        Re: Should I completely discharge my laptop battery? andymhancock@gmail.com - 2015-01-01 14:51 -0800
          Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-02 14:16 +1300
            Re: Should I completely discharge my laptop battery? andymhancock@gmail.com - 2015-01-01 18:11 -0800
              Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2015-01-02 01:15 -0800
                Re: Should I completely discharge my laptop battery? andymhancock@gmail.com - 2015-01-02 09:34 -0800
                Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2015-01-02 10:46 -0800
                Re: Should I completely discharge my laptop battery? andymhancock@gmail.com - 2015-01-02 14:25 -0800
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-04 12:28 +1300
                Re: Should I completely discharge my laptop battery? andymhancock@gmail.com - 2015-01-03 16:48 -0800
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-07 14:47 +1300
                Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2015-01-06 19:38 -0800
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-09 13:36 +1300
                Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2015-01-08 17:34 -0800
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-10 14:59 +1300
                Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2015-01-09 20:22 -0800
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-13 12:18 +1300
                Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2015-01-12 17:20 -0800
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-15 13:35 +1300
                Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2015-01-14 17:37 -0800
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-16 12:33 +1300
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-02-08 14:24 +1300
                Re: Should I completely discharge my laptop battery? mike <ham789@netzero.net> - 2015-02-07 21:02 -0800
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-02-11 11:09 +1300
                Re: Should I completely discharge my laptop battery? "~misfit~" <shaun.at.pukekohe@gmail.com> - 2015-01-03 11:47 +1300

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