AC Power on Battery Life

Is it detrimental/harmful for the battery if I use AC power all the time when using my notebook? (ie. plug in AC even when the charge on the battery is above >95%)

 

There are a million different theories about this, but here is mine. Lithium-ion batteries are consumable items, and will eventually wear out in a few years no matter what you do, even if it just sits on a shelf. Use it however is most convenient for you and don't worry about it, and when it dies buy another one if you still need it. The $100 replacement cost is not worth fussing over.

 

I'll echo what trwrt said. With the addition that what you specifically mentioned shouldn't hurt the battery. At least I don't think it would.

 

There are indeed quite a few opinions, but I'll let you decide based on the information below.

Quick quote from an old thread on this:

Here is the battery care guide in question: http://www.batteryuniversity.com/parttwo-34.htm

Notable points:

"The speed by which lithium-ion ages is governed by temperature and state-of-charge. Figure 1 illustrates the capacity loss as a function of these two parameters. High charge levels and elevated temperatures hasten permanent capacity loss."



"The worst condition is keeping a fully charged battery at elevated temperatures, which is the case with running laptop batteries. If used on main power, the battery inside a laptop will only last for 12-18 months. I must hasten to explain that the pack does not die suddenly but begins with reduced run-times."

"There are no remedies to restore lithium-ion once worn out. A momentary improvement in performance is noticeable when heating up the battery. This lowers the internal resistance momentarily but the condition reverts back to its former state when the temperature drops. Cold temperature will increase the internal resistance."

"If possible, store the battery in a cool place at about a 40% state-of-charge. Some reserve charge is needed to keep the battery and its protection circuit operational during prolonged storage. Avoid keeping the battery at full charge and high temperature. This is the case when placing a cell phone or spare battery in a hot car. Running a laptop computer on the mains has a similar temperature problem. While the battery is kept fully charged, the inside temperature during operation rises to 45°C (113°F)."

"Removing the battery from the laptop when running on fixed power protects the battery from heat."

 

I agree with all said except the chart I have disagreed with that chart from battery U since I first saw it. I have a 1 year 9 month notebook that did not start at 100% to begin with. It is on minimum 12 hrs a day sometimes 18 everyday. Wear level? 20% battery is always in so between 40 and 60 most of the day.

Also the 40% is only for longterm storage not a day or even a week but 3+ months.

I as a matter of choice keep battery in all the time. I like the convenience.