NY wrote:
Given that many modern laptops have an internal, non-removable battery that
cannot be exchanged when it stops holding its charge, what advice would
people give for maximising the lifetime of a battery? Every laptop I've
owned (98. XP, Vista, 7) has suffered from a battery that has a reduced life
(time that laptop will run on battery having been charged to 100%) which
soon degenerates into a battery which refuses to hold any charge at all, so
the laptop can only be used on mains.

In each case, the battery has been whatever the manufacturer (HP, Acer,
Samsung) has supplied, although when a battery has died, I've sometimes
replaced it with a cheap Chinese clone and not noticed that this dies any
sooner than the one that was supplied with the laptop.

I use my laptop mainly at a desk, where mains power is available, and I want
to leave my laptop in a state where the battery is reasonably fully charged
so I can always use it on battery at a moment's notice, without first having
to charge it for an hour or so.

I tend to run the laptop on mains when I'm using it (which charges the
battery) but I unplug it from mains when I notice that the battery is full
or once I've finished using it - so it does not spend many hours, days or
weeks being charged after it has reached 100%. Every week or so I run the
laptop on battery until the charge is down to about 20%, and then recharge
it - so the battery does go through partial discharge/charge cycles and does
not spend all its life at 100% charge.

Is there anything I should be doing differently so the battery won't die
after a couple of years? With an older laptop I could just replace the
battery, but it's more difficult when the battery is non-removable.

Should I run the laptop more often on battery (even when mains is available)
and accept that sometimes I will find that the battery is only partly
charged when I'd really want it full for maximum usage away from a mains
supply?

In addition to Paul's response - which covers most of the issues -,
you might want to read the thread "charging to 80 or 90%" of March 16 in
comp.mobile.android.

That thread is about phones/tablets, but they use the same battery
technology, so most is also applicable to laptops. The thread is only
122 articles, so an easy read! :-)

FWIW, I will be follwing *this* thread, because I'm also a
stationary-laptop user and 'hence' a battery-abuser.