(OT) Battery question

[kid joe]

Hi all,

Sorry this is a bit off-topic... but I do write a good amount of C code on
my laptop so there is a link...

Basically, it's a question about laptop batteries. About ten days ago, I
switched off my laptop with the battery fully charged. I haven't touched
it since then. This morning I turned it on, and the battery was
practically empty.

Is this a fault with the battery, or will a rechargable battery naturally
lose its charge over time even if it's not used? If so, how many days does
it take for the charge to seep away?

Thanks.

[Antoninus Twink]

On 28 Jun 2008 at 9:59, kid joe wrote:

Basically, it's a question about laptop batteries. About ten days ago, I
switched off my laptop with the battery fully charged. I haven't touched
it since then. This morning I turned it on, and the battery was
practically empty.

All batteries will discharge gradually with time. The rate of discharge
you describe sounds pretty fast to me, though - is it a very old
battery? But in any case it wouldn't really surprise me... I don't have
much faith in most laptop suppliers to produce high-quality batteries.

[viza]

On Sat, 28 Jun 2008 10:59:47 +0100, kid joe wrote:

Sorry this is a bit off-topic... but I do write a good amount of C code
on my laptop so there is a link...

Basically, it's a question about laptop batteries. About ten days ago, I
switched off my laptop with the battery fully charged. I haven't touched
it since then. This morning I turned it on, and the battery was
practically empty.

Is this a fault with the battery, or will a rechargable battery
naturally lose its charge over time even if it's not used? If so, how
many days does it take for the charge to seep away?

About ten days, apparently.

A new battery should not do this. If it is less than a year old take it
back. If it's older, then you have answered your own question.

[pete]

kid joe wrote:

Hi all,

Sorry this is a bit off-topic... but I do write a good amount of C code on
my laptop so there is a link...

Forget your laptop.
The Lexmark Model M, is the best keyboard for writing C code.

http://en.wikipedia.org/wiki/Model_M_keyboard

I'm using a 59G7980, right now.
I've got also got 1390131 and three 1391401's.

--
pete

[Antoninus Twink]

On 28 Jun 2008 at 11:30, pete wrote:

The Lexmark Model M, is the best keyboard for writing C code.

Don't you find the noise annoying?

[pete]

Antoninus Twink wrote:

On 28 Jun 2008 at 11:30, pete wrote:

>The Lexmark Model M, is the best keyboard for writing C code.

Don't you find the noise annoying?

It's like "the smell of napalm in the morning".
It all depends on what mental association you make with it.
I don't have to bottom out the keys to type,
so I never come anywhere near approaching jamming my knuckles.
Every time I use a keyboard that isn't a Model M, I wish it was.

What kind of shoes do you like best for wearing while C coding?
I prefer something without laces;
that makes it easy to slip them off and on, unobtrusively.

--
pete

[Antoninus Twink]

On 28 Jun 2008 at 12:23, pete wrote:

What kind of shoes do you like best for wearing while C coding? I
prefer something without laces; that makes it easy to slip them off
and on, unobtrusively.

I don't have strong feelings about shoes - do you think it makes a
difference? Normally I just wear whwatever's comfortable for going
around town, soft leather lace-ups.

[Richard Tobin]

In article <Wd******************************@earthlink.com> ,
pete <pf*****@mindspring.comwrote:

>The Lexmark Model M, is the best keyboard for writing C code.

Nonsense. The Sun type-2 was clearly the best.

-- Richard
--
Please remember to mention me / in tapes you leave behind.

[CBFalconer]

kid joe wrote:

>
Sorry this is a bit off-topic... but I do write a good amount of
C code on my laptop so there is a link...

Basically, it's a question about laptop batteries. About ten days
ago, I switched off my laptop with the battery fully charged. I
haven't touched it since then. This morning I turned it on, and
the battery was practically empty.

Try alt.comp.hardware.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

[Keith Thompson]

kid joe <sp******@spamtrap.invalidwrites:

Sorry this is a bit off-topic... but I do write a good amount of C code on
my laptop so there is a link...

Basically, it's a question about laptop batteries.

[...]

Did it even occur to you that there are good reasons to have more than
one newsgroup? Sheesh.

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[santosh]

Keith Thompson wrote:

kid joe <sp******@spamtrap.invalidwrites:

>Sorry this is a bit off-topic... but I do write a good amount of C
code on my laptop so there is a link...

Basically, it's a question about laptop batteries.

[...]

Did it even occur to you that there are good reasons to have more than
one newsgroup? Sheesh.

He is probably a sockpuppet of Mr. Twink.

[pete]

Antoninus Twink wrote:

On 28 Jun 2008 at 12:23, pete wrote:

>What kind of shoes do you like best for wearing while C coding? I
prefer something without laces; that makes it easy to slip them off
and on, unobtrusively.

I don't have strong feelings about shoes - do you think it makes a
difference? Normally I just wear whwatever's comfortable for going
around town, soft leather lace-ups.

I don't like to attract attention to my unshod feet in the office.
People talk too much
and managers make decisions based on the stupidest gossip.

--
pete

[pete]

Richard Tobin wrote:

In article <Wd******************************@earthlink.com> ,
pete <pf*****@mindspring.comwrote:

>The Lexmark Model M, is the best keyboard for writing C code.

Nonsense. The Sun type-2 was clearly the best.

What does it have to match the awesomeness of buckling springs?

--
pete

[Antoninus Twink]

On 28 Jun 2008 at 21:31, pete wrote:

I don't like to attract attention to my unshod feet in the office.
People talk too much and managers make decisions based on the
stupidest gossip.

Really? I can understand that the smell might be an issue if you're in a
shared office, but otherwise I can't imagine people objecting if you're
more comfortable without the shoes. It would be a different story if you
didn't have socks on - men's bare feet are singularly unpleasant things,
and I personally hate working with men who wear sandals during the
summer.

[Keith Thompson]

santosh <sa*********@gmail.comwrites:

Keith Thompson wrote:

kid joe <sp******@spamtrap.invalidwrites:

Sorry this is a bit off-topic... but I do write a good amount of C
code on my laptop so there is a link...

Basically, it's a question about laptop batteries.

[...]

Did it even occur to you that there are good reasons to have more than
one newsgroup? Sheesh.

He is probably a sockpuppet of Mr. Twink.

Conceivably, but I see no direct evidence of that (I haven't bothered
to check the headers).

I suggest that the tactic of accusing posters of sockpuppetry without
evidence be left to the trolls.

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[pete]

Antoninus Twink wrote:

On 28 Jun 2008 at 21:31, pete wrote:

>I don't like to attract attention to my unshod feet in the office.
People talk too much and managers make decisions based on the
stupidest gossip.

Really? I can understand that the smell might be an issue if you're in a
shared office, but otherwise I can't imagine people objecting if you're
more comfortable without the shoes.

Oh yes. People talk about the stupidest stuff.

When writing C programs at home,
pants or no pants?

--
pete

[Antoninus Twink]

On 28 Jun 2008 at 23:05, pete wrote:

Oh yes. People talk about the stupidest stuff.

Yes...

When writing C programs at home, pants or no pants?

Pants, definitely. Programming with no pants would be weird.

[Antoninus Twink]

On 28 Jun 2008 at 20:12, santosh wrote:

He is probably a sockpuppet of Mr. Twink.

Gotta love this assumption that there's *just no way* there can be *more
than one* person who doesn't believe in the hyper-restricted-topicality
dogma.

Actually I think the OP was wrong to label his post (OT) - batteries are
at least peripherally related to C programming, and in any case it's led
to an interesting (albeit somewhat surreal) discussion of footwear for C
programming.

[Richard Bos]

ri*****@cogsci.ed.ac.uk (Richard Tobin) wrote:

pete <pf*****@mindspring.comwrote:

The Lexmark Model M, is the best keyboard for writing C code.

Nonsense. The Sun type-2 was clearly the best.

Oh piffle. The original, rubber-square, Sinclair ZX Spectrum is
obviously the perfect programmer's keyboard.

(Shouldn't this thread be crossposted to alt.troll?)

Richard

[Wolfgang Draxinger]

kid joe wrote:

Hi all,

Sorry this is a bit off-topic... but I do write a good amount
of C code on my laptop so there is a link...

And there's a NG designated for laptop related questions
X-posting and F'up2 there.

Basically, it's a question about laptop batteries. About ten
days ago, I switched off my laptop with the battery fully
charged. I haven't touched it since then. This morning I turned
it on, and the battery was practically empty.

Could be caused by a two of things:
* Bad battery (ten days is a bit short for self discharge)
* You didn't switch off the laptop, but merely put it
into "Suspend to RAM state" (ten days is about the time it takes
my laptop to discharge the battery in suspend to RAM mode).
* Some leak currents flowing in the circuits. Could be a damage
of one of the power FETs, switching the battery lines. Those get
low resistant if damaged.

Is this a fault with the battery, or will a rechargable battery
naturally lose its charge over time even if it's not used? If
so, how many days does it take for the charge to seep away?

Yes/No, and Yes. Every battery will loose it's charge over time.
The rate of self discharge varies a lot by the type of battery,
capacity and age. In most laptops Li-Ion / Li-Polymer batteries
are used. Those have a mean lifetime of 3 years (they will age
no matter how you treat them). The ageing mostly affects the
capacity. Now if you deep discharge a Li-Ion battery you'll
damage it, but it will not loose capacity, but the ability to
hold charge over time. This kind of damage also accumulates over
time and is mostly caused by the charge/discharge cycles. The
deeper the cycles, the worse the damage. So in laymans terms:
Don't deep cycle Li-Ion/Li-Polymer batteries! This is different
to NiCd batteries, which should be deep cycled or the suffer
from memory effect. Li-Ion batteries don't have a Li-Ion
batteries don't have this effect, so hook up your laptop to a
power socket everytime you're near one.

Wolfgang Draxinger
--
E-Mail address works, Jabber: he******@jabber.org, ICQ: 134682867

[lawrence.jones]

Wolfgang Draxinger <wd********@darkstargames.dewrote:

>
This is different
to NiCd batteries, which should be deep cycled or the suffer
from memory effect.

That's folklore. NiCd's only suffer from the memory effect if they are
repeatedly charged and discharged to *exactly* the same points over and
over again, something which is impossible to achieve with consumer grade
electronics (it's only been observed in spacecraft). The most common
thing that NiCds suffer from is overcharging, which shortens their life
considerably and results in voltage depression, which makes them appear
to need recharging sooner than they really do, which leads to more
overcharging. A deep cycle eliminates the voltage depression, but it
also usually results in reverse charging of some cells of the battery,
which kills them even quicker than overcharging does.

The best way to get long life from NiCds is to use them normally until
the device indicates low battery (or, if the device doesn't have a low
battery indicator, you just start to notice degraded performance), then
recharge them in a good charger until it indicates they are fully
charged. Continuing to use them after the low battery indication,
regular deep cycling, and leaving them in a charger that doesn't shut
off will all reduce their lifetimes.

-- Larry Jones

When you're as far ahead of the class as I am, it doesn't take much time.
-- Calvin

[M.I.5¾]

<la************@siemens.comwrote in message
news:im************@jones.homeip.net...

Wolfgang Draxinger <wd********@darkstargames.dewrote:

>>
This is different
to NiCd batteries, which should be deep cycled or the suffer
from memory effect.

That's folklore. NiCd's only suffer from the memory effect if they are
repeatedly charged and discharged to *exactly* the same points over and
over again, something which is impossible to achieve with consumer grade
electronics (it's only been observed in spacecraft). The most common
thing that NiCds suffer from is overcharging, which shortens their life
considerably and results in voltage depression, which makes them appear
to need recharging sooner than they really do, which leads to more
overcharging. A deep cycle eliminates the voltage depression, but it
also usually results in reverse charging of some cells of the battery,
which kills them even quicker than overcharging does.

The best way to get long life from NiCds is to use them normally until
the device indicates low battery (or, if the device doesn't have a low
battery indicator, you just start to notice degraded performance), then
recharge them in a good charger until it indicates they are fully
charged. Continuing to use them after the low battery indication,
regular deep cycling, and leaving them in a charger that doesn't shut
off will all reduce their lifetimes.

A nice post which demonstrates perfectly that haven't got the faintest idea
what you talking about. You seem to have strung together a list of small
snippets that you have heard down the pub or stumbled across on the
internet.

First 'voltage depression' is a phenomenon that affects Ni-MH batteries
*not* Ni-Cd. Second fully discharging (to 0v) Ni-Cd batteries is not
injurous to them in any way (however reverse charging individual cells is,
which is what tends to happen when you discharge batteries of cells (because
the cells are not of identical capacity)).

Space craft do not use N-Cd batteries - they use Silver-Zinc rechargeable
batteries which have numerous advantages, the main one being a far greater
energy density. The enormously high cost is incidental in space craft
budget terms,

And you totally failed to mention the one phenomenon that shortens the life
of Ni-Cd (and Ni-MH come to that) more than any other. The growth of nickel
whiskers between the anode and the cathode which provide a current path and
it looks like the non existent memory effect - which really doesn't exist at
all, except in the minds of Ni-MH battery marketting men.

[lawrence.jones]

"M.I.5?" <no****@no.where.no_spam.co.ukwrote:

>
A nice post which demonstrates perfectly that haven't got the faintest idea
what you talking about. You seem to have strung together a list of small
snippets that you have heard down the pub or stumbled across on the
internet.

Ditto.

First 'voltage depression' is a phenomenon that affects Ni-MH batteries
*not* Ni-Cd.

Wrong. It affects both, but every source I've seen agrees that NiCd is
affected far more than NiMH.

Second fully discharging (to 0v) Ni-Cd batteries is not
injurous to them in any way (however reverse charging individual cells is,
which is what tends to happen when you discharge batteries of cells (because
the cells are not of identical capacity)).

The definition of a "battery" is multiple cells. As you (and I) said,
fully discharging a NiCd *cell* is not injurious (and can be
beneficial), but fully discharging a NiCd *battery* almost certainly
causes reverse charging of some cells, which can cause damage.

Space craft do not use N-Cd batteries - they use Silver-Zinc rechargeable

It depends on the specific application. NiCd is used as well.

And you totally failed to mention the one phenomenon that shortens the life
of Ni-Cd (and Ni-MH come to that) more than any other. The growth of nickel
whiskers between the anode and the cathode which provide a current path and

The major cause of dendrite growth is reverse changing, which I did
mention.

it looks like the non existent memory effect - which really doesn't exist at
all, except in the minds of Ni-MH battery marketting men.

It does exist, just not under normal conditions.

-- Larry Jones

Hmph. -- Calvin

[M.I.5¾]

<la************@siemens.comwrote in message
news:dn************@jones.homeip.net...

"M.I.5?" <no****@no.where.no_spam.co.ukwrote:

>>
A nice post which demonstrates perfectly that haven't got the faintest
idea
what you talking about. You seem to have strung together a list of small
snippets that you have heard down the pub or stumbled across on the
internet.

Ditto.

>First 'voltage depression' is a phenomenon that affects Ni-MH batteries
*not* Ni-Cd.

Wrong. It affects both, but every source I've seen agrees that NiCd is
affected far more than NiMH.

I'm not wrong.

>Second fully discharging (to 0v) Ni-Cd batteries is not
injurous to them in any way (however reverse charging individual cells
is,
which is what tends to happen when you discharge batteries of cells
(because
the cells are not of identical capacity)).

The definition of a "battery" is multiple cells. As you (and I) said,
fully discharging a NiCd *cell* is not injurious (and can be
beneficial), but fully discharging a NiCd *battery* almost certainly
causes reverse charging of some cells, which can cause damage.

>Space craft do not use N-Cd batteries - they use Silver-Zinc rechargeable

It depends on the specific application. NiCd is used as well.

I am not aware of any spacecraft application where Ni-Cd batteries were
used. They are far too heavy for their miniscule energy density. No
designer in his right mind would use them. Virtually every rechargeable
technology, with the exception of lead-acid, is better than Ni-Cd in both
regards. Silver-Zinc is much lighter and has a far greater energy density
(in fact at the time it was the best). The advantages are so great that the
Apollo moon landings used them for the moon buggys in spite of the fact that
they were never going to be charged. The weight and energy density
advantages beat even primary battery technology of the day.

>And you totally failed to mention the one phenomenon that shortens the
life
of Ni-Cd (and Ni-MH come to that) more than any other. The growth of
nickel
whiskers between the anode and the cathode which provide a current path
and

The major cause of dendrite growth is reverse changing, which I did
mention.

No. Dendrite growth will occur in any Ni-Cd battery. Reverse charging is
not necesary. It is a feature of the nickel and not ofthe chemistry. Hence
it occurs in Ni-MH as well.

>it looks like the non existent memory effect - which really doesn't exist
at
all, except in the minds of Ni-MH battery marketting men.

It does exist, just not under normal conditions.

Memory Effect does not exist. The term itself didn't even exist until the
Mi-MH marketeers invented it to try and justify people buying a technology
that offered (at the time) little advantage for a considereable cost hike.
Even the battery makers now acknowledge this. There is no mechanism under
which it could exist.

By the way, I work in the aerospace industry and see a good many batteries
(including some fairly esoteric designs).