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Re: Dead battery after storage on T400s

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Computer Nerd Kev <not@telling.you.invalid> wrote:
> bp@www.zefox.net wrote:
>> Turns out I searched the manual for "battery testing" and variations,
>> but the test points were revealed under   "charging". My bad....
>> 
>> With the battery status at 99% the removed battery measures 12.2 volts,
>> which seems pretty good. The run-time still seems short however.
> 
> The "battery status" charge percentage is a measure of the battery
> voltage by the computer, so not surprising that it looks good at
> 99% charged. The symptoms sound like a typical worn out battery.
>
 
After charging the battery fully in the t400s and removing it the
battery measured about 12.17 volts. Allowed to sit overnight on the
countertop it decayed to 12.13 volts, so it isn't internally leaky.

After putting the battery back in and booting the t400s the capacity
indicated 99% but the advertised run time was slightly under two hours.
That seems rather short, I think the claimed runtime is closer to five.
Still, if it's true, the laptop is usable to some extent. The most obvious
use is to run an Owon vds1022i usb oscilloscope, which will mostly be done
within reach of power.

A new battery is still worth considering, any suggestions are welcome.
Is it feasible to repair (by replacing cells) the original pack?

>> It further turns out that the power button was set to sleep, not shutdown.
> 
> Well that explains the fast self-discharge. Some laptops do seem to
> wear down the battery more when stored for a long time than if
> the battery is removed. I'm not sure if the T400s is one of those,
> but it shouldn't discharge as quickly as you describe if it was
> fully turned off.
> 

It never crossed my mind that "off" might be something other than off....8-(

>> One pleasant surprise is that the machine seems to work fine with the
>> battery physically removed.
> 
> I think every laptop I've encountered worked fine without a
> battery.
>

This is the first laptop I've ever messed with personally.  

Thanks for writing,

bob prohaska
 

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Dead battery after storage on T400s bp@www.zefox.net - 2025-01-14 01:50 +0000
  Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-01-14 18:11 +0000
    Re: Dead battery after storage on T400s not@telling.you.invalid (Computer Nerd Kev) - 2025-01-15 06:40 +1000
      Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-01-15 17:25 +0000
        Re: Dead battery after storage on T400s Adrian Caspersz <email@here.invalid> - 2025-01-15 21:02 +0000
          Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-01-15 22:03 +0000
        Re: Dead battery after storage on T400s not@telling.you.invalid (Computer Nerd Kev) - 2025-01-16 07:44 +1000
          Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-01-15 22:45 +0000
            Re: Dead battery after storage on T400s Computer Nerd Kev <not@telling.you.invalid> - 2025-01-16 13:47 +1000
              Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-01-16 16:10 +0000
                Re: Dead battery after storage on T400s Computer Nerd Kev <not@telling.you.invalid> - 2025-01-17 12:53 +1000
                Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-01-17 04:26 +0000
                Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-02-07 19:05 +0000
                Re: Dead battery after storage on T400s not@telling.you.invalid (Computer Nerd Kev) - 2025-02-08 07:49 +1000
                Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-02-08 20:33 +0000
                Re: Dead battery after storage on T400s not@telling.you.invalid (Computer Nerd Kev) - 2025-02-09 09:54 +1000
                Re: Dead battery after storage on T400s bp@www.zefox.net - 2025-02-09 01:44 +0000

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