Running on AC Power only?

[SingingWolf]

I keep hearing conflicting opinions about running devices such as the Surface Pro using only AC power. Anyone know whether this does - or does not - reduce battery life?

 

[anon(5335877)]

I keep hearing conflicting opinions about running devices such as the Surface Pro using only AC power. Anyone know whether this does - or does not - reduce battery life?

What do you mean reduce battery life? Battery life as in how long it takes for it to go from 100% to 0, or it's ability to retain a charge as it ages?

At least for laptops, I heard you shouldn't run it on AC all the time because you'll reduce it's ability to hold a charge. Some people, including me, have done that, and the battery won't hold a charge anymore after like a year or two.

 

[SingingWolf]

I'm referring to the latter: the ability to retain a charge as it ages. What you stated about your experience with laptops is what I had heard, but your the first to note you have had direct experience with this issue.

Thanks for the help.

 

[Dewg_Zom]

The issue with Lithium Ion batteries is that they have a certain number of charge cycles they can do. It's pretty high, but let's say 1000 for the sake of illustration. Each time you plug in your power supply, and start a charge into the battery that counts as one of your charge cycles (even if it's full or nearly full when you do). So if you plug it in every day, that's 365 charge cycles a year. If you unplug it for a meeting and then plug it back in afterwards, that's 2 cycles that day. Take this to it's logical conclusion and you can see why electronic batteries last about 2-3 years.

 

[zhuz]

The issue with Lithium Ion batteries is that they have a certain number of charge cycles they can do. It's pretty high, but let's say 1000 for the sake of illustration. Each time you plug in your power supply, and start a charge into the battery that counts as one of your charge cycles (even if it's full or nearly full when you do). So if you plug it in every day, that's 365 charge cycles a year. If you unplug it for a meeting and then plug it back in afterwards, that's 2 cycles that day. Take this to it's logical conclusion and you can see why electronic batteries last about 2-3 years.

That completely untrue
A charge cycle is a battery going from fully charged, to depleted, to fully charged (fully depleting a li-ion battery is not good for it, so try to avoid it.)

Do you think if I just sit here plugging and unplugging my laptop 1000 times, the battery will die?

The best way to increase the life of your battery is to leave it plugged in. But don't be one of those people who obsesses so much about the battery life that you don't take advantage of the amazing portability of the surface

 

[anon(5335877)]

That completely untrue
A charge cycle is a battery going from fully charged, to depleted, to fully charged (fully depleting a li-ion battery is not good for it, so try to avoid it.)

Do you think if I just sit here plugging and unplugging my laptop 1000 times, the battery will die?

The best way to increase the life of your battery is to leave it plugged in. But don't be one of those people who obsesses so much about the battery life that you don't take advantage of the amazing portability of the surface

You shouldn't leave it plugged in all the time. I did that, and my laptop battery died within a year. No longer holds a charge, not even a little.

You're right that the other poster was incorrect, each time you plug and unplug the charger doesn't count as a charge cycle. One charge cycle is from fully charged to fully depleted, however, it doesn't have to be all at once. It can be split up. For example, I go from 100% to 50% then charge it to full. The next day, I do the same thing. That's one charge cycle, because 50% * 2 = 100%.

I think the reason you shouldn't leave it plugged in all the time is because Li-ion batteries don't like being fully charged, or fully discharged. That doesn't mean you can't do it, but if you really want to extend the life of your battery, you want to keep it in the middle, like between 20% and 80%.

So you can leave it plugged in, but do run it on battery from time to time.

Read:
Battery Life in Gadgets - The Science of Battery Life in Electronics - Popular Mechanics
Maximizing the lifespan of a laptop battery | Computerworld Blogs

Even Apple says you shouldn't leave a laptop plugged in all the time:
Apple - Batteries - Notebooks

 

[KingCrimson]

The Surface has no AC power input, it runs strictly off battery.

 

[jeffinthomas1]

Here is a link to a great article about lithium ion batteries. A must read I would say. All facts stated here are based on test conducted in a controlled environment.
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries