Laptop batteries

[Ben Stevenson]

The laptop that I have is used mostly at home. It is plugged into the mains
all the time with the batteries in. Now I have been told thaat this is not
the way to do things. Within a year the batteries will only last about 20
mins when used outdoors without a mains plug, because the batteries
deteriorate significantly when constantly plugged in due to overcharging and
what else.

I've been told that when used at home with the laptop plugged into the
mains, the batteries should be removed to preserve them. I don't know how
far this is true and what are the facts. I hope the gurus here can offer the
appropriate advise.
Thanks

 

[Kenny]

On my Advent at the POST screen before Windows loads there's a battery
refresh option which takes the battery through a charge/discharge cycle
which extends battery life.

 

[Doug]

Some good information.

http://www.batteryuniversity.com/parttwo-34.htm

Personally I keep a battery in the laptop all the time to act as an
uninterruptable power supply and to make life simple when I do need to take
the computer and go. I keep the laptop on one of those USB powered coolers
with three fans. It keeps the laptop pretty cool and after 5 years the
original battery still lasts almost two hours with the (15.4" WUXGA) screen
on full bright and running a PCMCIA wireless adapter.

I keep a second newer battery in the fridge with a 40~50% charge. I take it
out, let it warm and charge it for trips etc...

Another less expensive option, if you're concerned about power dips/outages
while plugged into the wall would be to get a small capacity UPS and run
with the laptop battery out.

D

 

[David B.]

It has been my experience that if the battery doesn't get used, it fails
fairly quickly (1 year, more or less). I would not remove it, what I would
to is unplug the power supply once or twice a week and run off the battery
till it suspends itself, then plug back in.

 

[TRCSr]

This is exactly what I do and my battery has the same capacity as it had
when new 2 years ago. I believe that continual charging of the battery is
not good for it. Also, I would not use the computer off of the mains without
a battery in it as I believe the battery provides protection from surges and
line noise.

TRCSr

 

[David B.]

I doubt the battery provides any surge (over volt) protection, brownouts
(under voltage) yes.

 

[Ian D]

This is exactly what I do and my battery has the same capacity as it had
when new 2 years ago. I believe that continual charging of the battery is
not good for it. Also, I would not use the computer off of the mains
without a battery in it as I believe the battery provides protection from
surges and line noise.

TRCSr

The laptop battery does not provide protection from surges or line noise.
It's the power supply brick that performs that function. During AC
operation, the only connection between the laptop and battery is through
the charging circuitry. If DC power from the power supply is interrupted,
the battery is almost instantaneously switched in to provide power. Most
power bricks can compensate for AC power sags to 95-100 volts. If a true
brownout occurs the brick should shut off DC power to the laptop, and the
battery will take over if present.