Plugged in when fully charged = broken battery?

[Elrohir]

I've had lots of people tell me that electronic devices that run off of batteries (Laptops, iPods, cell phones, etc) have their batteries degrade in quality if left plugged in after the device is charged and eventually won't hold a charge for as long. I haven't observed this myself, but given my tendency to do this sort of thing -- leave my laptop plugged in as a matter of course, charge my phone overnight as I sleep, and so on -- I'd rather know if this is the case. I can't seem to find much good information online though; some say it's true, others say that this was only true with older battery technology, and new devices don't have this problem.

Do you guys know what's actually true or false about this? I'd appreciate any reliable information anyone can provide.

 

[Zelig]

Not a problem, lithium-polymer batteries have built-in chips to stop charging when they're fully charged, otherwise they would catch fire and such.

It is bad in the sense that it's generally time that your battery will spend sitting at a higher temperature than if the device were turned off, which wears down batteries more quickly than lower temperatures.

 

[Elrohir]

Thanks!

 

[Skwink]

I have my Laptop plugged in almost 24/7.