Does mains power kill laptop batteries?

Numerous times over the years I have heard it said that leaving a laptop plugged into the mains other than while it is charging will shorten the life of the battery.

I have seen some anecdotal 'evidence' from a couple of friends who use DTR or larger notebook machines as home desktop setups. A few of them have mentioned having to change batteries more often than they should. However I have never read or seem anything at all conclusive on the subject.

 

Most modern laptops do not continuously charge the battery, They wait until the charge has dropped a few per cent before topping up the charge.

This should reduce the loss of battery life due to unnecessary recharge cycles. I look on the battery as being a built-in UPS as well as a source of power when away from the mains.

John

 

Yes, I always leave my battery in as a UPS.

 

yeah. Too bad my old 800MHz P3 laptop that I use for a server has no such protections I was looking forward to having a built-in UPS in the unit. No such luck. Doesn't even hold a charge any more, like, at all. Fortunately, it's also a low power draw, so I can plug it into my real UPS and not worry about it.

 

There was a thread somewhere around here about the ACPI control chips on batteries functioning incorrectly and giving a false reading of battery power.

Quite possibly that is what happens for some.

As to having your laptop plugged in all the time causing problems, it shouldnt unless your laptop uses sub-par charging circuitry which would have caused you problems such as dead power regulation circuitry anyways... Toshiba Satellite A60 and A70 being an example

 

It does not. I leave my laptop pluged in for extended periods of time. Sometimes as long as a week 24/7. I've had it for over a year and the battery still gives me over 2.5 hours of use.

 

Consult the battery info guide by chrisyano here for detailed information.

 

My battery is typically removed from my laptop at a 40% charge since I don't move it much. When I do go portable, obviously I put it in and let it charge first.

 

Your battery will lose life regardless of what you do to try to stop that degradation. What you can control, to a degree, is the rate at which it ages.

As mentioned, this is covered in the battery guide.

 

OK thanks for all the responses guys.