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Dead battery after storage on T400s

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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

#564 — Dead battery after storage on T400s

The T400s I was given  a few years ago successfully upgraded to 
Windows 10 and seemed to work reasonably well for its age.

However, after not-very-prolonged storage it's absolutely dead,
not responding to the power button until it's plugged into an
AC adapter. This is despite being put away with a full charge
and being shut down, not set to sleep or hibernate 

Once it comes back up it charges the battery in an hour or two
and claims to have about 90 minutes of runtime with the battery
at 90-ish percent of full. That seems rather brief, but it's an
old machine. I don't mind plugging it in, but stone-dead from
the start is sort of a nuisance. 

What's reasonable to expect? The hardware manual seems mute on
the subject. I've looked into replacing the battery, which is
marked 42t4690, 11.1 volts 3.9AH 44WH. It appears to be available
on Amazon, with admittedly vague descriptions. Still, it would be 
nice to know how to test the battery before replacing it. There are
far too many contacts to start probing blindly. 

Thanks for reading, and any suggestions!

bob prohaska
 

 

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#565

bp@www.zefox.net wrote:
> The T400s I was given  a few years ago successfully upgraded to 
> Windows 10 and seemed to work reasonably well for its age.
> 
> However, after not-very-prolonged storage it's absolutely dead,
> not responding to the power button until it's plugged into an
> AC adapter. This is despite being put away with a full charge
> and being shut down, not set to sleep or hibernate 
> 
> Once it comes back up it charges the battery in an hour or two
> and claims to have about 90 minutes of runtime with the battery
> at 90-ish percent of full. That seems rather brief, but it's an
> old machine. I don't mind plugging it in, but stone-dead from
> the start is sort of a nuisance. 
> 
> What's reasonable to expect? The hardware manual seems mute on
> the subject. I've looked into replacing the battery, which is
> marked 42t4690, 11.1 volts 3.9AH 44WH. It appears to be available
> on Amazon, with admittedly vague descriptions. Still, it would be 
> nice to know how to test the battery before replacing it. There are
> far too many contacts to start probing blindly. 
> 
> Thanks for reading, and any suggestions!

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.

It further turns out that the power button was set to sleep, not shutdown.
That's fixed now, so maybe it won't be totally dead after storage.

One pleasant surprise is that the machine seems to work fine with the
battery physically removed. In the worst case I can use it that way.
I'll keep the battery out overnight to see how much the voltage drops.
Can't find a date code on the battery, if anybody knows a way to check
that would be helpful.

Thanks for reading, apologies for the misinformed questions!

bob prohaska

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#566

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.

> 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.

> 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.

-- 
__          __
#_ < |\| |< _#

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#567

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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#568

On 15/01/2025 17:25, bp@www.zefox.net wrote:

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

A compatible T400s battery here (UK) is about £24

https://www.amazon.co.uk/Onlyguo-3800MAH-42T4690-Replacement-ThinkPad/dp/B07YDLHXCY


Cheap. I'd get one before they get scarce, and sellers stop trading them.

-- 
Adrian C

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#570

Adrian Caspersz <email@here.invalid> wrote:
> On 15/01/2025 17:25, bp@www.zefox.net wrote:
> 
>> A new battery is still worth considering, any suggestions are welcome.
>> Is it feasible to repair (by replacing cells) the original pack?
>> 
> 
> A compatible T400s battery here (UK) is about £24
> 
> https://www.amazon.co.uk/Onlyguo-3800MAH-42T4690-Replacement-ThinkPad/dp/B07YDLHXCY
> 
> 
> Cheap. I'd get one before they get scarce, and sellers stop trading them.

Interesting. Twenty four pounds is only about $30, I think. Not sure how an
international transaction would work from my existing Amazon account. 

 
There is a rough US equivalent for $84, under
https://www.amazon.com/CIESIA-Replacement-Battery-42T4688-42T4689/dp/B0DDNV3D6B?crid=1GDCAZ54G2VD0&dib=eyJ2IjoiMSJ9.DEDqL4tj-JVXiffdITBpkw.A2XkcaikmH5sPa8gHsSHoTFMk2zyd4gwBO72ZzHWMhk&dib_tag=se&keywords=42T4691&qid=1736977404&sprefix=42t4691%2Caps%2C327&sr=8-1

Only 16 ratings of the UK part, none at all for the US part.  
Looks like they're already scarce....

I'm going to save the link and keep watching for a bit. The idea of an
international order makes me a little uneasy. 

Thanks for writing!

bob prohaska

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#569

bp@www.zefox.net wrote:
> Computer Nerd Kev <not@telling.you.invalid> wrote:
> 
> 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.

My fear is always of dodgy Chinese Li-Ion batteries burning my
house down, but few seem to care about that in spite of the
ever-rising Li-Ion fire statistics.

> Is it feasible to repair (by replacing cells) the original pack?

I've done that, replacing with cells from a battery from a broken
laptop. The tricky thing is that the battery cases are all stuck
together differently. Some are plastic welded, others
snap-together, others glued (with glue of various strengths). The
battery I dismantled for cells ended up a shredded mess of plastic
due to strong glue, but the plastic welded case for the battery I
was re-celling came apart without much damage.

If attempting that, you do want to remember that denting,
puncturing, or shorting out a Li-Ion cell can all cause it to
catch fire, sometimes after a delay or when charging.

If you do trust the Chinese reproduction batteries, note that
they're often not much more expensive than buying enough new
individual Li-Ion cells (except maybe for the most dodgy
unbranded Li-Ion cells).

-- 
__          __
#_ < |\| |< _#

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#571

Computer Nerd Kev <not@telling.you.invalid> wrote:
> bp@www.zefox.net wrote:
>> Computer Nerd Kev <not@telling.you.invalid> wrote:
>> 
>> 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.
> 
> My fear is always of dodgy Chinese Li-Ion batteries burning my
> house down, but few seem to care about that in spite of the
> ever-rising Li-Ion fire statistics.
> 
>> Is it feasible to repair (by replacing cells) the original pack?
> 
> I've done that, replacing with cells from a battery from a broken
> laptop. The tricky thing is that the battery cases are all stuck
> together differently. Some are plastic welded, others
> snap-together, others glued (with glue of various strengths). The
> battery I dismantled for cells ended up a shredded mess of plastic
> due to strong glue, but the plastic welded case for the battery I
> was re-celling came apart without much damage.
> 
> If attempting that, you do want to remember that denting,
> puncturing, or shorting out a Li-Ion cell can all cause it to
> catch fire, sometimes after a delay or when charging.
> 
> If you do trust the Chinese reproduction batteries, note that
> they're often not much more expensive than buying enough new
> individual Li-Ion cells (except maybe for the most dodgy
> unbranded Li-Ion cells).

I wondered about re-celling the old battery pack, but couldn't
find any descriptions of folks actually doing it and one demo
of letting the magic smoke out, so I'm wary. It's also unclear
what kind of cells are required. 

In the meantime I set the power button to shut down while on both
battery and mains. Turned the machine off, it seemed to do so.
Couple hours later I noticed the machine was warm, opened the lid,
found it was up and running. Re-checked "what the power buttons do"
and they still claimed to cause shut down. This looks like a bug.
Anybody else seen this behavior? 

If it won't stay off that's a curious problem

Thanks for writing,

bob prohaska

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#572

bp@www.zefox.net wrote:
> Computer Nerd Kev <not@telling.you.invalid> wrote:
>> bp@www.zefox.net wrote:
>>> Computer Nerd Kev <not@telling.you.invalid> wrote:
>> I've done that, replacing with cells from a battery from a broken
>> laptop. The tricky thing is that the battery cases are all stuck
>> together differently. Some are plastic welded, others
>> snap-together, others glued (with glue of various strengths). The
>> battery I dismantled for cells ended up a shredded mess of plastic
>> due to strong glue, but the plastic welded case for the battery I
>> was re-celling came apart without much damage.
>> 
>> If attempting that, you do want to remember that denting,
>> puncturing, or shorting out a Li-Ion cell can all cause it to
>> catch fire, sometimes after a delay or when charging.
>> 
>> If you do trust the Chinese reproduction batteries, note that
>> they're often not much more expensive than buying enough new
>> individual Li-Ion cells (except maybe for the most dodgy
>> unbranded Li-Ion cells).
> 
> I wondered about re-celling the old battery pack, but couldn't
> find any descriptions of folks actually doing it and one demo
> of letting the magic smoke out, so I'm wary.

Seems like there are videos on YouTube, though I made it up as I
went along since it's just a case of hooking things up like they
were when you started (after fighting your way in). I've read some
battery controllers might 'die' when you disconnect the old cells
if you don't hook external power to them, so they're tricky.

> It's also unclear what kind of cells are required. 

The type of Li-Ion cell is almost always 18650. The capacity (mAh)
is the only thing that varies, and can be calculated by comparing
the battery circuit (add up the capacity of the batteries in
parallel) with the capacity of the battery pack if it's not printed
on the cells themselves (often it is). Note that over-stated
capacity figures are a common complaint with cheap Chinese
replacement cells. You can also choose to use different capacity
cells, but the OS's battery hours estimate might be wrong then.

You will need cells with solder tags attached so you can wire them
up. They are usually crammed together tight in the battery pack so
it can be tricky.

> In the meantime I set the power button to shut down while on both
> battery and mains. Turned the machine off, it seemed to do so.
> Couple hours later I noticed the machine was warm, opened the lid,
> found it was up and running. Re-checked "what the power buttons do"
> and they still claimed to cause shut down. This looks like a bug.
> Anybody else seen this behavior? 

Sometimes I've had thinkpads intermittently fail to fully turn off
at shut-down, just sit running with a black screen and maybe the
CPU fan running. Holding the power button down for a while forces
them off. It doesn't boot back up though, just hangs, so it must be
a bug.

You could check that Wake on LAN is disabled in the BIOS settings.

-- 
__          __
#_ < |\| |< _#

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#573

Computer Nerd Kev <not@telling.you.invalid> wrote:
> bp@www.zefox.net wrote:
>> Computer Nerd Kev <not@telling.you.invalid> wrote:
>>> bp@www.zefox.net wrote:
>>>> Computer Nerd Kev <not@telling.you.invalid> wrote:
>>> I've done that, replacing with cells from a battery from a broken
>>> laptop. The tricky thing is that the battery cases are all stuck
>>> together differently. Some are plastic welded, others
>>> snap-together, others glued (with glue of various strengths). The
>>> battery I dismantled for cells ended up a shredded mess of plastic
>>> due to strong glue, but the plastic welded case for the battery I
>>> was re-celling came apart without much damage.
>>> 
>>> If attempting that, you do want to remember that denting,
>>> puncturing, or shorting out a Li-Ion cell can all cause it to
>>> catch fire, sometimes after a delay or when charging.
>>> 
>>> If you do trust the Chinese reproduction batteries, note that
>>> they're often not much more expensive than buying enough new
>>> individual Li-Ion cells (except maybe for the most dodgy
>>> unbranded Li-Ion cells).
>> 
>> I wondered about re-celling the old battery pack, but couldn't
>> find any descriptions of folks actually doing it and one demo
>> of letting the magic smoke out, so I'm wary.
> 
> Seems like there are videos on YouTube, though I made it up as I
> went along since it's just a case of hooking things up like they
> were when you started (after fighting your way in). I've read some
> battery controllers might 'die' when you disconnect the old cells
> if you don't hook external power to them, so they're tricky.
> 
>> It's also unclear what kind of cells are required. 
> 
> The type of Li-Ion cell is almost always 18650. The capacity (mAh)
> is the only thing that varies, and can be calculated by comparing
> the battery circuit (add up the capacity of the batteries in
> parallel) with the capacity of the battery pack if it's not printed
> on the cells themselves (often it is). Note that over-stated
> capacity figures are a common complaint with cheap Chinese
> replacement cells. You can also choose to use different capacity
> cells, but the OS's battery hours estimate might be wrong then.
> 

I can't see how the cells could be 18650, the pack is only about
half an inch thick. Even AA cells are too thick to fit. Maybe that's
why replacement packs seem scarce.

> You will need cells with solder tags attached so you can wire them
> up. They are usually crammed together tight in the battery pack so
> it can be tricky.
> 
>> In the meantime I set the power button to shut down while on both
>> battery and mains. Turned the machine off, it seemed to do so.
>> Couple hours later I noticed the machine was warm, opened the lid,
>> found it was up and running. Re-checked "what the power buttons do"
>> and they still claimed to cause shut down. This looks like a bug.
>> Anybody else seen this behavior? 
> 
> Sometimes I've had thinkpads intermittently fail to fully turn off
> at shut-down, just sit running with a black screen and maybe the
> CPU fan running. Holding the power button down for a while forces
> them off. It doesn't boot back up though, just hangs, so it must be
> a bug.
> 
> You could check that Wake on LAN is disabled in the BIOS settings.
>
 
I looked for wake on LAN, but couldn't find it in the BIOS. Might it
be set in Windows 10? Haven't seen it there, but I'm mostly unfamiliar
with Win10 and could easily miss it. I'm certain I didn't hit the power
button, but did unplug and plug the power jack and also open/close the
lid. Could either trigger a startup?

The machine stayed off all night, when I checked the battery this morning
it read 12.26 volts, same as last night. No parasite drain. Knowing now
where to test voltage direct on the battery I'm tempted to apply a small
light bulb load, say 2 amps, to do a capacity check independent of the
computer. Any hint what the several intermediate contact on the battery do?

Thanks for writing!

bob prohaska
 
 

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#574

bp@www.zefox.net wrote:
> Computer Nerd Kev <not@telling.you.invalid> wrote:
>> bp@www.zefox.net wrote:
>>> Computer Nerd Kev <not@telling.you.invalid> wrote:
>>>> bp@www.zefox.net wrote:
>>> 
>>> I wondered about re-celling the old battery pack, but couldn't
>>> find any descriptions of folks actually doing it and one demo
>>> of letting the magic smoke out, so I'm wary.
>> 
>> Seems like there are videos on YouTube, though I made it up as I
>> went along since it's just a case of hooking things up like they
>> were when you started (after fighting your way in). I've read some
>> battery controllers might 'die' when you disconnect the old cells
>> if you don't hook external power to them, so they're tricky.
>> 
>>> It's also unclear what kind of cells are required. 
>> 
>> The type of Li-Ion cell is almost always 18650. The capacity (mAh)
>> is the only thing that varies, and can be calculated by comparing
>> the battery circuit (add up the capacity of the batteries in
>> parallel) with the capacity of the battery pack if it's not printed
>> on the cells themselves (often it is). Note that over-stated
>> capacity figures are a common complaint with cheap Chinese
>> replacement cells. You can also choose to use different capacity
>> cells, but the OS's battery hours estimate might be wrong then.
>> 
> 
> I can't see how the cells could be 18650, the pack is only about
> half an inch thick. Even AA cells are too thick to fit.

OK, might be the flat cells like they use in phones.

> Maybe that's why replacement packs seem scarce.

Seems like Lenovo might still be making them actually. Quite a few
sellers claiming to have genuine "Thinkpad battery 59+" in stock,
if that's the right one.

>>> In the meantime I set the power button to shut down while on both
>>> battery and mains. Turned the machine off, it seemed to do so.
>>> Couple hours later I noticed the machine was warm, opened the lid,
>>> found it was up and running. Re-checked "what the power buttons do"
>>> and they still claimed to cause shut down. This looks like a bug.
>>> Anybody else seen this behavior? 
>> 
>> Sometimes I've had thinkpads intermittently fail to fully turn off
>> at shut-down, just sit running with a black screen and maybe the
>> CPU fan running. Holding the power button down for a while forces
>> them off. It doesn't boot back up though, just hangs, so it must be
>> a bug.
>> 
>> You could check that Wake on LAN is disabled in the BIOS settings.
>>
> 
> I looked for wake on LAN, but couldn't find it in the BIOS. Might it
> be set in Windows 10?

I doubt it, usually it's set in the BIOS. I've seen the option on
earlier Thinkpads, believe it or not the T400s is still a bit too
new for me.

> Haven't seen it there, but I'm mostly unfamiliar
> with Win10 and could easily miss it. I'm certain I didn't hit the power
> button, but did unplug and plug the power jack and also open/close the
> lid. Could either trigger a startup?

I wouldn't have thought so, unless the OS didn't really shut down
fully after all.

> The machine stayed off all night, when I checked the battery this morning
> it read 12.26 volts, same as last night. No parasite drain. Knowing now
> where to test voltage direct on the battery I'm tempted to apply a small
> light bulb load, say 2 amps, to do a capacity check independent of the
> computer.

Not recommended. Over-discharge could kill it, or even cause it to
catch fire when you try to charge it again (although the battery
controller should prevent that).

> Any hint what the several intermediate contact on the battery do?

They're so the battery controller can talk to the PC and tell it
things like why it doesn't want to charge because someone hooked
a light bulb to it and over-discharged it.

-- 
__          __
#_ < |\| |< _#

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#575

Computer Nerd Kev <not@telling.you.invalid> wrote:
> bp@www.zefox.net wrote:
>> I can't see how the cells could be 18650, the pack is only about
>> half an inch thick. Even AA cells are too thick to fit.
> 
> OK, might be the flat cells like they use in phones.
> 
>> Maybe that's why replacement packs seem scarce.
> 
> Seems like Lenovo might still be making them actually. Quite a few
> sellers claiming to have genuine "Thinkpad battery 59+" in stock,
> if that's the right one.
> 

That must be laptopbatteryexpress.com. Not OEM, but Lenovo reports
out of stock on the numbers that might work: The battery I have is 
42t4690, apparently 42t4691 and 42t4688 will work.

With shipping a generic replacement is about $90, with only two ratings,
one awful and one good, from Amazon in the USA.

>> I looked for wake on LAN, but couldn't find it in the BIOS. Might it
>> be set in Windows 10?
> 
> I doubt it, usually it's set in the BIOS. I've seen the option on
> earlier Thinkpads, believe it or not the T400s is still a bit too
> new for me.
> 
>> Haven't seen it there, but I'm mostly unfamiliar
>> with Win10 and could easily miss it. I'm certain I didn't hit the power
>> button, but did unplug and plug the power jack and also open/close the
>> lid. Could either trigger a startup?
> 
> I wouldn't have thought so, unless the OS didn't really shut down
> fully after all.
> 
>> The machine stayed off all night, when I checked the battery this morning
>> it read 12.26 volts, same as last night. No parasite drain. Knowing now
>> where to test voltage direct on the battery I'm tempted to apply a small
>> light bulb load, say 2 amps, to do a capacity check independent of the
>> computer.
> 
> Not recommended. Over-discharge could kill it, or even cause it to
> catch fire when you try to charge it again (although the battery
> controller should prevent that).
> 
>> Any hint what the several intermediate contact on the battery do?
> 
> They're so the battery controller can talk to the PC and tell it
> things like why it doesn't want to charge because someone hooked
> a light bulb to it and over-discharged it.
> 

Point taken, I didn't intend to let it run down to dead.  Certainly
mistakes can be made, nonetheless. Having watched a couple of rundown
cycles it appears that both laptop and battery are working correctly,
with the battery having a little over one hour of endurance. That's ok
for the present. The core error I made was not realizing the power-off
button was only putting the machine to sleep. Now it's turning off
for real and does seem to remain off. Self-discharge isn't a problem,
after all is said and done.

Thanks for writing, and all your help!

bob prohaska

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#580

bp@www.zefox.net wrote:
> The core error I made was not realizing the power-off
> button was only putting the machine to sleep. Now it's turning off
> for real and does seem to remain off. Self-discharge isn't a problem,
> after all is said and done.

After some deliberation I ordered a battery from amazon for slightly
under $100, on the thesis that at least I'd avoid creating another online
identity and the returns are fairly straightforward.

It arrived more than a month early, which seemed odd. It seems to fit with
a little fiddling, though the plastic case is very slightly warped.

I settled on a test cycle of simply letting the machine idle without
sleeping, using the "best battery life" performance setting. The new battery,
after the suggested three charge/discharge cycles, yielded around 4.5 hours
till self-shutdown.

When I repeated the test with the original battery, the run time seemed to
be around 4 hours. The longest run times reported on-line were maybe five
hours, though it's not clear what the test settings for power were.

Does anybody have a sense whether this is reasonable? I'm told the original
battery dates from the purchase time, around 2009. I think it was taken out
of service around 2020 and given to me in 2024, so the oem battery is about
fifteen years old. I'm very surpised the old battery works so well, if in
fact the as-new runtime was five hours..

Thanks for reading, and any sanity checking 8-)

bob prohaska

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#581

bp@www.zefox.net wrote:
> It arrived more than a month early, which seemed odd. It seems to fit with
> a little fiddling, though the plastic case is very slightly warped.
> 
> I settled on a test cycle of simply letting the machine idle without
> sleeping, using the "best battery life" performance setting. The new battery,
> after the suggested three charge/discharge cycles, yielded around 4.5 hours
> till self-shutdown.
> 
> When I repeated the test with the original battery, the run time seemed to
> be around 4 hours. The longest run times reported on-line were maybe five
> hours, though it's not clear what the test settings for power were.
> 
> Does anybody have a sense whether this is reasonable? I'm told the original
> battery dates from the purchase time, around 2009. I think it was taken out
> of service around 2020 and given to me in 2024, so the oem battery is about
> fifteen years old. I'm very surpised the old battery works so well, if in
> fact the as-new runtime was five hours..
> 
> Thanks for reading, and any sanity checking 8-)

I'd say the main inconsistency here is that in your previous post
you said you tested discharging the old battery and it had a
"little over one hour of endurance". Yet now it lasts four hours?!

A difference in run time like that makes no sense to me unless
you were working it hard or had power-hungry devices plugged into
it during the first test. I guess Windows could also have been
doing an upgrade in the background before, if you didn't disable
that during the test (or, since it's Windows, if it ignored you and
did something anyway).

-- 
__          __
#_ < |\| |< _#

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#582

Computer Nerd Kev <not@telling.you.invalid> wrote:
> 
> I'd say the main inconsistency here is that in your previous post
> you said you tested discharging the old battery and it had a
> "little over one hour of endurance". Yet now it lasts four hours?!
> 
I didn't become aware of the various low-power adjustments until
after that series of experiments.  I considered doing a manual
capacity test, but decided against it being convinced a battery
that old couldn't be much good and not wanting to harm it more.
So, I ordered CS-IBT400NB from ShenZhen HENZENS Technology Co. via
Amazon with fingers crossed.

> A difference in run time like that makes no sense to me unless
> you were working it hard or had power-hungry devices plugged into
> it during the first test. I guess Windows could also have been
> doing an upgrade in the background before, if you didn't disable
> that during the test (or, since it's Windows, if it ignored you and
> did something anyway).

After I got the new battery and started exercising it per the seller's
directions (which did seem to improve the performance) I gradually
learned about low power settings. When the new battery clocked in at
only 4.5 hours at low power settings, I got curious and re-tested the
old battery with the new settings. Lo and behold, they were similar.
The new battery is better, but for ~100$ not by much. 

I'm left wondering:
1. could a fifteen your old battery still have 80% capacity?
2. should a new 4400 mAh battery last more than 4.5 hours?
3. is there some better (more reproducible) way to test the batteries?

Thanks for writing!

bob prohaska
 
 

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#583

bp@www.zefox.net wrote:
> Computer Nerd Kev <not@telling.you.invalid> wrote:
>> A difference in run time like that makes no sense to me unless
>> you were working it hard or had power-hungry devices plugged into
>> it during the first test. I guess Windows could also have been
>> doing an upgrade in the background before, if you didn't disable
>> that during the test (or, since it's Windows, if it ignored you and
>> did something anyway).
> 
> After I got the new battery and started exercising it per the seller's
> directions (which did seem to improve the performance) I gradually
> learned about low power settings. When the new battery clocked in at
> only 4.5 hours at low power settings, I got curious and re-tested the
> old battery with the new settings. Lo and behold, they were similar.
> The new battery is better, but for ~100$ not by much. 

You are actually timing how long until it automatically shuts down
due to running out of charge, not just going from the estimated
time remaining, right? Those estimations aren't reliable with old
batteries.

> I'm left wondering:
> 1. could a fifteen your old battery still have 80% capacity?

Discharge/recharge cycles are quoted as the key factor for battery
aging, so it might fit if the battery was never used much.

> 2. should a new 4400 mAh battery last more than 4.5 hours?

Was the screen on/off for both the old "little over one hour" test
and the new tests? I don't know what's normal for a T400s, but
details like that and whether you were using it or just letting it
sit would be important for getting a real answer.

-- 
__          __
#_ < |\| |< _#

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#584

Computer Nerd Kev <not@telling.you.invalid> wrote:
> bp@www.zefox.net wrote:
>> Computer Nerd Kev <not@telling.you.invalid> wrote:
>>> A difference in run time like that makes no sense to me unless
>>> you were working it hard or had power-hungry devices plugged into
>>> it during the first test. I guess Windows could also have been
>>> doing an upgrade in the background before, if you didn't disable
>>> that during the test (or, since it's Windows, if it ignored you and
>>> did something anyway).
>> 
>> After I got the new battery and started exercising it per the seller's
>> directions (which did seem to improve the performance) I gradually
>> learned about low power settings. When the new battery clocked in at
>> only 4.5 hours at low power settings, I got curious and re-tested the
>> old battery with the new settings. Lo and behold, they were similar.
>> The new battery is better, but for ~100$ not by much. 
> 
> You are actually timing how long until it automatically shuts down
> due to running out of charge, not just going from the estimated
> time remaining, right? Those estimations aren't reliable with old
> batteries.
> 
I tried to keep track of time to self-power-off. The machine was
idle, in the sense that I wasn't actively using it except to check
when I should take another look. WiFi was on, screen blanking was
automatic on a short (few minutes) interval. 


>> I'm left wondering:
>> 1. could a fifteen your old battery still have 80% capacity?
> 
> Discharge/recharge cycles are quoted as the key factor for battery
> aging, so it might fit if the battery was never used much.
> 
I have no information on how much the machine was used. It's
in very nice condition but that's more likely due to a fatidious
owner than lack of use. Most batteries are said to have a calendar
life along with a cycle life, so I figured calendar would be the
limiting factor. Maybe not. 

>> 2. should a new 4400 mAh battery last more than 4.5 hours?
> 
> Was the screen on/off for both the old "little over one hour" test
> and the new tests? I don't know what's normal for a T400s, but
> details like that and whether you were using it or just letting it
> sit would be important for getting a real answer.

The "little over an hour" tests were done when I didn't know about
the power control settings. Those obviously mattered hugely.

The screen blanking was left as it was for the initial tests. I think
5 minutes after keyboard/mouse activity, maybe 10. So, how often I
checked made some difference but I tried to be consistent.

At one point I found a review claiming 2 hours and change playing
a DVD but could find no dvd-playing program in the default Win10
system. Would playing a DVD be a more reproducible test?

In practice, what I have is what I got 8-) It works well enough
for my purposes, but it would be nice to find a reliable test
of the battery condition. To my surprise the T400S Hardware
Maintenance Manual seems mute on run times. I was hoping there's
some piece of software that writes battery output energy to disk
under some consistent loading benchmark. Guess not.  

Thanks for writing,

bob prohaska

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