Yes to the former, but (hopefully a real battery expert can chime in here) my understanding is that lithium-ion batteries cannot be float/trickle charged safely. Their internal resistance is too non-linear and it's too easy even with a "full" battery to provide a voltage that will sink dangerous amounts of current and overheat.

All lithium ion technologies I'm aware of require active current and temperature monitoring.

Probably 90% of the time I'm using my laptops is when I'm actually sitting at my desk and they are always plugged in at that time. I recently read where someone else had stated that it was good to remove the battery (if you can) if using the laptop with external power.

Any idea if this this accurate or will prolong battery life? I've got an (almost) brand new Thinkpad with a large, expensive battery that I'd like to preserve as much as possible (like anyone else).

I don’t know if this applies to other notebooks but at least Apple used to recommend that you do not remove the battery [0]. There’s a little more discussion on Super User [1] but there seems to be no definite answer.

[0]: http://web.archive.org/web/20130615084258/http://support.app... [1]: http://superuser.com/a/12842

At least some Thinkpads used to let you limit the charge on the battery.

Capping the charge at something like 60% is a great way to preserve the battery if you're not going to need all that battery life.

Storing at 40%-60% elongates the life compared to 100% or 0%.

All of this is 2nd hand, and I have no particular expertise to validate this comment.

I don't understand. So with this setting people are artificially limiting their battery capacity to 40%, in order to preserve capacity they're not going to use? Meanwhile you'd have to ride a battery pretty hard to grind it down to 40% health, it'd take many years probably.

I'm not sure what the average lifetime of a laptop is, but I'd be surprised if it's more than 8 years. What's the upside if the battery is well preserved at the time when the device is being replaced? Let's say with normal usage the battery will perform at an average of 80% over its lifetime, that's still better than 40% - for the same money.