Home     |     .Net Programming    |     cSharp Home    |     Sql Server Home    |     Javascript / Client Side Development     |     Ajax Programming

Ruby on Rails Development     |     Perl Programming     |     C Programming Language     |     C++ Programming     |     IT Jobs

Python Programming Language     |     Laptop Suggestions?    |     TCL Scripting     |     Fortran Programming     |     Scheme Programming Language


 
 
Cervo Technologies
The Right Source to Outsource

MS Dynamics CRM 3.0

What others think of your Laptop?

battery stays in all the time or not?


I run my laptop +90% of the time on AC. - rarely on battery power.
I have charged the battery and removed it while running AC.

what is the opinion of the group regarding this method?

My thinking is that the fewer times it is subjected to even a partial
recharge, the better it is for the battery.
The only drawback I can see is during those rare occasions of a power
failure..

Dave.

--
Posted via a free Usenet account from http://www.teranews.com

"Dave" <sylnd@yahoo.ca> wrote in message

news:46434477$0$16360$88260bb3@free.teranews.com...
>I run my laptop +90% of the time on AC. - rarely on battery power.
> I have charged the battery and removed it while running AC.

> what is the opinion of the group regarding this method?

> My thinking is that the fewer times it is subjected to even a partial
> recharge, the better it is for the battery.
> The only drawback I can see is during those rare occasions of a power
> failure..

I do the same thing. A small UPS can be had for around $20 that will solve
the power failure problem.

-----------------------------------------------Reply-----------------------------------------------
The consensus is that you are doing the right thing.  Leaving a battery
in place in your situation tends to destroy them in 2 years +/-.  [And I
service laptops and I see this a lot].

My only other comments are:

1.  The battery does need some "exercise" every 2-3 months, and the
manufacturers all say that Lithium ion batteries store best at about 60%
rather than full charge (however, I have not observed a significant
difference in that regard).

2.  Consider getting a low-end UPS (350VA or so, about $30) to protect
against power failures while using the laptop.  It's still cheaper ... a
LOT cheaper ... than a $200 battery.

In my experience power failure comes from things like tripping over the
cable to the laptop, or on an older laptop a loose fitting barrel
connector. In these cases a UPS is of no help.

-----------------------------------------------Reply-----------------------------------------------

"Salvador Freemanson" <s@gohome.com> wrote in message

news:46438ca0$0$24924$426a34cc@news.free.fr...

so then use your $200 battery all the time. "You pays your money and you
takes your choice"

-----------------------------------------------Reply-----------------------------------------------
My Dell E1405 is fitted with the extended (8.5 hours spec, 7.5
hours in reality) battery, which is about $75 incl shipping on
eBay. I find it a great luxury to use it on my lap without a
power cable. And, there have been times when I got stuck
somewhere and either read a book or watched a movie while
waiting. If the difference is a new battery more often, the
amortized cost is insignificant compared to the convenience.

-----------------------------------------------Reply-----------------------------------------------
Hey, like the man says, you pays your money and you takes your choice.
It's your battery and your money.

olfart wrote:

> so then use your $200 battery all the time. "You pays your money and you
> takes your choice"

My solution is to use an old battery which can last for a few minutes
when the laptop is on mains. I only use my new battery when I am mobile.

-----------------------------------------------Reply-----------------------------------------------
Hi Barry,

I've got two hardly used Sony BP71 batteries which won't charge after
leaving them out for about 4-5 months. Do you know of a fix? I guess
they are too deep discharged.

Jaap

Barry Watzman wrote:
> The consensus is that you are doing the right thing.  Leaving a battery
> in place in your situation tends to destroy them in 2 years +/-.  [And I
> service laptops and I see this a lot].

> My only other comments are:

> 1.  The battery does need some "exercise" every 2-3 months, and the
> manufacturers all say that Lithium ion batteries store best at about 60%
> rather than full charge (however, I have not observed a significant
> difference in that regard).

[...]

-----------------------------------------------Reply-----------------------------------------------
"jaap" <f@xs4all.nl> wrote in message

news:4646d805$0$12424$e4fe514c@dreader15.news.xs4all.nl

> Hi Barry,

> I've got two hardly used Sony BP71 batteries which won't charge after
> leaving them out for about 4-5 months. Do you know of a fix? I guess
> they are too deep discharged.

> Jaap

Yes, the charger will refuse to charge too low Li-Ion batteries. This is
a safety thing. As overly discharged Li-Ion can explode.

--
Bill

-----------------------------------------------Reply-----------------------------------------------

BillW50 schreef:

> "jaap" <f@xs4all.nl> wrote in message
> news:4646d805$0$12424$e4fe514c@dreader15.news.xs4all.nl
>> Hi Barry,

>> I've got two hardly used Sony BP71 batteries which won't charge after
>> leaving them out for about 4-5 months. Do you know of a fix? I guess
>> they are too deep discharged.

>> Jaap

> Yes, the charger will refuse to charge too low Li-Ion batteries. This is
> a safety thing. As overly discharged Li-Ion can explode.

Hmm, it would be a waste to discard them because of this reason. Does
anyone have access to the documentation on the 6 pin header on these
batteries? I'd like to put 16 to 18Vdc on them through a current
limiting resistor. Only to get a light charge so the notebook will
address them properly.

-----------------------------------------------Reply-----------------------------------------------
I know of no way to fix that.  Once lithium batteries discharge below a
critical point, they are shot.  Usually, it takes 1-2 years for a fully
charged battery to get that low, but sometimes it can happen sooner.

Occasionally, however, I've been able to get batteries back above the
critical level by simply plugging them into a charger repeatedly (they
charge for just a few seconds before the charger shuts down).  In the
end, however, even when apparently successful, those batteries never
really held a good charge.

FORGET IT.

First, you can't do anything externally.  There is an entire
Microprocessor inside the battery, it has "control" of the battery, and
it won't let you ANYTHING that could be dangerous from outside the battery.

Second, the danger here is very real.  Don't screw around with this, a
lithium battery can turn into a fire-bomb.  You could be looking at this:

http://cache.gizmodo.com/assets/resources/2006/08/dell_fire.jpg

Almost instantly, before you can get away.

It's a series connection of cells and if not matched there will be one
cell reversing polarity eventually. I guess that's what causing the
deterioration of Li-ion batteries. In the good'ol days we had NiCads
which didn't suffer from this problem as much (but from other problems).
I kept a 1998 200MHz notebook, still going strong on it's original NiCad
battery :)

Will try the fiddling with the battery you suggested. Thanks.

Thanks for the warning.
One starts to wonder if manufacturers build in 'deterioration' logic
instead of making things more reliable. I certainly won't buy a Sony
notebook again, that's for sure. 230 down the drain, tsk!

For the technically fearless:

I've disassembled laptop batteries a few times and replaced
cells with new ones that are typically of higher capacity than
the originals. It's fairly easy to do, and there are a couple of
guides online (one of which I contributed to). Just a few tools,
an hour or so, and you can have an improved battery for less
than half the cost of a replacement.

There are several Asian sources for cells at much lower prices
than published U.S. sources. I prefer "aw", who has a sort of
store on candlepowerforums.com - reliable, incredibly
cost-effective, etc.

Using the same source and approach, it's possible to assemble an
external set of cells that can operate a laptop and recharge the
internal battery via the power jack. I have one that ran my
previous laptop - a P4 3GHz - for six hours using 3.7V 18650
cells in series-parallel, and a regulator! It's a little tricky,
and works only on those units that have a two-conductor power
jack, but in some situations this is great to have.

Just remember: a battery or cell, by definition, is packed with
energy that can be released slowly to power an electrical
device, or suddenly and explosively if you are not careful.

-----------------------------------------------Reply-----------------------------------------------

Appreciate your input Ike. Do the cells need to be matched (power
capacity) to last longer, or are tolerances tight these days?

-----------------------------------------------Reply-----------------------------------------------
I have done this with Ni Cad and NiMH batteries, but I don't recommend
it or do it for Lithium batteries.  This is EXTREMELY dangerous, the
laptop and the onboard microprocessor THINK that they know the
characteristics of the cells, but when you have changed the cells, their
information is incorrect and the results can be disastrous.

Barry's right in that building a battery can be hazardous.
However, friends and I have done it many times over the past
decade, in nickel-metal-hydride and lithium ion, without
problem. Apparently the intelligent management circuit doesn't
depend upon a charge/discharge profile in ROM (which would be
specific to the cells used), but adapts.

That does NOT guarantee that you'll be lucky...

-----------------------------------------------Reply-----------------------------------------------

"Ike" <binarydot@gmail.com> wrote in message

news:46479681$0$9877$4c368faf@roadrunner.com

> Barry's right in that building a battery can be hazardous.
> However, friends and I have done it many times over the past
> decade, in nickel-metal-hydride and lithium ion, without
> problem. Apparently the intelligent management circuit doesn't
> depend upon a charge/discharge profile in ROM (which would be
> specific to the cells used), but adapts.

> That does NOT guarantee that you'll be lucky...

There are professionals who do this all of the time. This isn't one of
them, but I found it on Google. I can't say if they are 100% correct or
not.

http://www.electronics-lab.com/articles/Li_Ion_reconstruct/index.html

--
Bill

-----------------------------------------------Reply-----------------------------------------------

"Barry Watzman" <WatzmanNOS@neo.rr.com> wrote in message

news:46472738$0$9897$4c368faf@roadrunner.com...

>I know of no way to fix that.  Once lithium batteries discharge below a
>critical point, they are shot.  Usually, it takes 1-2 years for a fully
>charged battery to get that low, but sometimes it can happen sooner.

> Occasionally, however, I've been able to get batteries back above the
> critical level by simply plugging them into a charger repeatedly (they
> charge for just a few seconds before the charger shuts down).  In the end,
> however, even when apparently successful, those batteries never really
> held a good charge.

You are lucky.  The chemistry of Lithum ion batteries is such that when the
charge state has dropped low enough (a little less 3.0 volts per cell),
copper is thrown out of the electrolyte which coats the internal structure
of the cell.  This provides an alternative discharge path.  If there is
enough of this copper, it can create a discharge path that will cause the
cell to rupture and explode.  This is why chargers are set up not to charge
overdischarged batteries.  There is no means by which the copper can be
drawn back into the chemistry.

Since the copper deposition is a time and temperature related phenomenon
(not to mention a few other variables), it is often possible to recover an
over discharged battery that been in this condition for a short time only
(not more than a few days).  The battery can be recovered by passing a small
charging current to bring the voltage above 3.2 volts per cell*.  The
battery can then be charged normally, but this should be done in a location
where there is nothing that you would like to see destroyed within 6 feet of
the battery.  Leave the charged battery for 24 hours in this location.
After that, normal use can be continued, but expect the battery to self
discharge faster than normal.

*Many battery constructions have internal circuitry to prevent even this
remedial technique.

-----------------------------------------------Reply-----------------------------------------------

"jaap" <f@xs4all.nl> wrote in message

news:46472da5$0$12430$e4fe514c@dreader15.news.xs4all.nl...

> It's a series connection of cells and if not matched there will be one
> cell reversing polarity eventually. I guess that's what causing the
> deterioration of Li-ion batteries. In the good'ol days we had NiCads which
> didn't suffer from this problem as much (but from other problems). I kept
> a 1998 200MHz notebook, still going strong on it's original NiCad battery
> :)

> Will try the fiddling with the battery you suggested. Thanks.

In multiple series cell constructions (and in many cases series/parallel),
the battery internal electronics will (or should!) monitor the individual
cells.  The monitor should prevent the entire battery from being charged if
*any* cell falls below 3.0 volts.  Similarly, it ends the discharge when any
cell falls below 3.2 volts.

Add to del.icio.us | Digg this | Stumble it | Powered by Megasolutions Inc