Is it alright to leave the battery in the laptop on AC for 24 hours?

Is it alright to do that? Will it harm the battery? thanks

 

yes it's fine, won't harm the battery

 

The battery won't be overcharged when it's fully charged, so that's not a problem.

However, keeping it at 100% charge all the time and never using it isn't the best usage scenario.

If you're running Windows 7, use the sony Battery Care utility to set the target charge to 80% or less, that would be slightly better for the battery. I mean, you might as well.

 

ok i guess i will unplug it sometimes

 

If you plan on leaving it tied to the wall wart for longer than a couple of days at at time, and really don't use it that much away from a plug... I agree with shurcooL. Set the Battery Care utility to keep it at 80%. If you want a visual of your battery health, download BatteryBar. It's a great piece of freeware that I'd recommend to everyone. Also, since I LOVE BatteryBar so much, if you end up liking it, try going for the pro version, it's great!

 

1.If you have VAIO Control center, go "Power Management"> "Battery" and enable "Battery care function"

2.When it reaches the preset 50% or 80% it will simply stop charging the battery and run directly from AC power, if power goes out, it will switch back to battery allowing you to continue....so best of both worlds.

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But the problem is the battery will continue to lose power even when the vaio is connected to the AC power adapter so what will happen is it will keep recharging the battery like 79% -> 80%, then after a while it drops back to 79% -> 80%. Now imagine this cycle over and over for like 24 hours or days. That can't possibly be good for the battery.

The first thing I do if I know the vaio is gonna be on the AC outlet for like a long time is remove the battery.

 

From what I've seen it won't....atleast not frequently

 

The reason for this isn't that being fully charged is bad for a Li-ION battery (rather the opposite), but because Li-ION batteries have a non-linear discharge curve.
When at 100%, it discharges much faster than when it's lower.

So if NOT keeping the laptop constantly on AC, it will self-discharge much faster when at 100% than at 80%. This puts more wear on the battery and shortens its life span. Normal "mixed" use with mostly AC but occasional battery use would do well with this.

However, if you DO keep the AC connected at all times, keep it at 100%. The battery will trickle-charge and stay at 100% without noticeable battery wear.

And if you almost exclusively use the machine on AC, but keep it unplugged and unused for long periods of time, set it at 50%. The self-discharge rate is lowest for Li-ION batteries at around 40-50%, so this will cause the least amount of wear. (A typical scenario for this is when travelling between two places, but using it on AC both places)

 

Aren't those constant trickle-charges bad for the battery ? Wouldn't it be better to just remove the battery and let it self-discharge if you almost exclusively use the vaio on AC power ?

 

From what I heard small trickle-charges are better than large drops to 0% and than giant charge back to 100%.

 

Trickle-charging to keep a certain charge level isn't bad for modern batteries. It's the full-power charging that causes heat and "wear".
I've used a Palm PDA for almost 10 years now, and most of the time, it sits in its cradle, trickle-charging whenever needed to keep it "topped off". I can still use it to read books for several hours. My wife's PDA, on the other hand, no longer holds a charge, because her habit was to only charge it when it needed it.

 

For Lithium-based batteries, this is true.
It's the old heavy metal based batteries that should get a full discharge every now and then to work at peak efficiency and avoid "memory" effects -- with Li-ION batteries, you only reduce your battery lifespan and max charge by doing that.

 

@arth1 - what do you recommend for this kind of use:

At home (AC power) I use it like average 3 hours per day.

Out of home (batteries) usually like 2 or 3 times per week I need to take it out and use it on batteries.

1 - How should I set battery care for this kind of use ?
2 - At home should I leave it always on AC power even when not using it ?

 

Unless you run out of battery capacity, 80% seems a good compromise for "mixed use".
If you do run out of batteries, though, keep it at 100%, because it's better to run from 100% to 20% than it is to run from 80% to 0% -- running a Li-ION battery all the way down to "empty" is always going to reduce its capacity.

 

thanks for the tips.

I'll take the opportunity to ask another question related to batteries but kinda offtopic.

My Vaio P had an option in Vaio Control Center to "quick charge" or "slow charge" and I remember the description said something along the lines of "if you set to slow charge you can prolong battery life".

Now that I got a Vaio Z11 I don't see this option anymore in Vaio Control Center. Is there any way to force a slow charge ?