still have a laptop battery question

I want to know how leaving the laptop's battery in with the ac adapter plugged in affects the battery.
Lithium ion batteries have a limited number of charge cycles before they die, so when the laptop is plugged in with the battery, does it draw power from the battery directly, while the battery is continually charged? or does it bypass the battery and draw power from the ac adapter, like it would if the battery wasn't plugged in at all?

Of course there's a lot more to the issue but I'm just asking about where the laptop draws it's power from. If it goes through the battery even with the ac adapter plugged in that would use up the charge cycles of the battery faster.

I've read a few articles and forum threads about lithium ion batteries in laptops and I haven't found the answer to this yet.

 

You haven't looked hard enough.

Basically, (while you keep looking for the latest thread on this very subject) don't worry about it. The battery will last as long as it wants too anyway.

The cooler you can keep the notebook (and thus, the battery too) the less damage the continuous use of the AC adaptor will have on the battery.

 

For your specific question, in pretty much every notebook I've ever seen (I'm allowing for possible odd exceptions), if the notebook is plugged in, it will draw power from the mains and none from the battery. It will not drain the battery unless it cannot draw enough power from the mains (this can happen if your PSU is underpowered, either deliberately or through damage), at which point it will draw what it can from the mains and the rest from the battery. Once the battery is fully charged, it will stop charging the battery and just supply power to the notebook directly. The reason batteries need to be charged when the notebook sits for a while even when off is because lithium-ion batteries self-discharge; even if they're not being used, they lose some charge over time.

 

Thanks a lot. I was hoping that's how they worked. I wanted to find out because I remember an apple guy telling me that my old ipod wouldn't work when the battery completely died even if it was plugged in.

 

Yeah this is known as trickle charging IIRC.

 

from what I read on apple's website, it's good to use they battery once in a while, to keep the electrons moving. They suggest not use the battery till it dies, but use it for 30mins-1 hour, then plug in to charge. Li-Ion batteries don't like to be run low, they like to be "topped up" My laptop is my desktop replacement, so it's almost always plugged in, but now I'm trying to use battery power for an hour min. once every 2-3 days, to keep the battery healthy. If you remove the battery to store it, it's best stored at 60% charge (and never fully charged!)

 

Best stored at 40% charged not 60%.

 

Well, iPods aren't notebooks, and may not necessarily operate the same. I'm pretty sure that most cell phones, for example, always operate off the battery, so even if plugged in, the power goes through the battery first so the battery is always being drained. So if you iPod is more like an iPhone, then that might be the case (note, I don't actually know if this is how iPods/iPhones operate).