Do laptop batteries have a memory? Should I run it dead before charing?

do laptop batteries get ruined if you don't run them almost dead? or does it not matter if i plug it in whenever i want?

 

Maybe if this was 1993 it would have mattered, but this is 2009, and it does not matter anymore. Charge your battery whenever you want.

 

Laptops of today use Li-Ion batteries. Contrary to the past, these batteries do not need to be discharged fully before a recharge. Deep discharging Li-Ion batteries actually hurt them more than a recharge at around 20%.

 

I learned this the Hard way, Never ever run your Lithium Ion laptop batteries down to Zero, it will ruin them. And could harm you Laptop.

 

Here is a great thread with information about your battery: NBR Battery Guide

You might also want to check out the battery university, but that can be heavy going for some people: Battery University

In short though, modern Li-on or Li-poly batteries such as those used in notebooks and mobile phones don't have a memory like older types of rechargeable batteries.

 

This is also a good article, much 'lighter' than Battery U

http://www.reghardware.co.uk/2009/05/07/beginners_battery_maintenance/

Even shorter version:

* Running the battery from 100% all the way down and recharging it to 100% is one charge cycle.

* Running the battery from 100% down to 50%, recharging it to 100%, running it back down to 50% and recharging back to 100% again is one charge cycle.

* On average, after around 300 cycles the battery will only hold 80% of its original capacity.

That said - I have had a Sony Ericsson K750i which has a Lithium Ion battery for around 5-6 years now, I would always run the battery all the way down before charging (even running the video player on a loop to tax the CPU to drain the last bit out) and it's still going strong. Same for a Nokia 8210 before that, and I would still get around 11 days (!!) standby out of it when I stopped using it.

Also - I (and other people I work with) have had weird memory effects with Li-Ion batteries, not a permanent reduction like with Ni-Cad/NiMH but where you will go down to 15-20% and then from there the battery lasts much longer than you expect it to - running it all the way down and recharging clears this.

 

what about if your going to be plugged in most of the time??? Can you remove the battery and stay plugged in on the Studio series? Or do you have to have your battery in the whole time? if this is the case I will rarely use the battery as I am going to be plugged in at home and at work...
And also what kind of drain or usage comes off the battery if it is being charged while using it most of the time?...
Thanks!

 

but it is beneficial nevertheless from a li-ion battery chemistry point of view, to prevent top up charging repeatedly like from 95 to 100%. Also every month you should do discharge to around 5 percent then charge up to 100%, to make sure that the anodes and cathodes are free from irreversible residue build up, which will cause a battery cell failure prematurely.

 

My Studio 17 runs fine without a battery.

 

Thanks! +rep

 

Whilst you can run it without the battery in, you do of course lose what is effectively a UPS by doing so. If you do this, remember to store the battery properly - otherwise you're not really gaining much except a miniscule amount of increased life due to impact of temperature on the battery.

 

And there's the risk of getting dust/dirt in the battery slot or even cracking the case on some laptops.

And never let the battery fully discharge.