Notebook batteries, not meant to last?

[Claymonkey]

Hardly conclusive since it's limited to two laptops in this test. However this is interesting.


http://www.hardwareanalysis.com/cont...meant-to-last/

Ever since I switched from using a desktop PC to a notebook for all of my daily computer tasks I never bothered to look back. It is just so convenient to always be able to carry all your work with you wherever you go. In reality I am not much of a road warrior though so most of the time the notebook sits on my desk for weeks on end attached to its docking station.

Obviously when plugged into the mains during the day the notebook's battery never gets used. However every time you turn the notebook off at the end of the day it will drain the battery ever so slightly overnight and will start to top it off again when it gets turned back on. The question is whether that will wear down the battery quicker than if you simply drain the battery and then reconnect the notebook to the mains adapter to recharge it a few times a day?

Over the past eight months I have done exactly that experiment, by using two identical notebooks. One has been connected to the mains adapter all the time, being used for approximately eight hours every day, the other has had its battery drained and recharged, usually once a day, but has also been running for eight hours every day. The results are somewhat surprising. The notebook that has been connected to the mains has a flat battery now, basically you get about ten maybe twenty minutes worth of power out of it before the notebook goes into standby. The notebook that has had its battery cycled does not offer the plus four hours of battery life it used to give, but is still good for more than three hours of use.

So although hardly conclusive it does provide some insights into why some notebook batteries go flat after not being used for months. The topping off that occurs after every power cycle when connected to the mains could very well be putting more wear on the battery than actually draining it fully and recharging it once or twice a day. Maybe notebook manufacturers should make mention of this? Or allow for the battery to drop to 80% of its capacity prior to topping it off again? The latter might reduce the total running time for the notebook on batteries by a mere few minutes, but could prove worthwhile for the longevity of the battery pack. Or, this could just be a 'feature' which ties in with the three months warranty that is usually applicable to notebook batteries which boosts the sales of overpriced replacements.

[Jammrock]

It's called the "memory effect".

http://en.wikipedia.org/wiki/Memory_effect

All rechrageable batteries should be drained at least once a week, once a month at the least. If you never put your battery through a full discharge/charge cycle it drastically reduces its life. This is why I never recharge anything every day unless it really does run out of battery life every day.

When I did desktop a toshiba rep said you should never have your battery in your laptopm if you plan on using it with AC power. That way your battery has a much less chance of getting hit by a memory issue. I don't do this mind you, but I do run my battery down a lot.

Even with all that said, you can only expect 2-3 years max out of your battery, even with proper care. There are some new designs that are supposed to give you 3-5 years of good battery life. The 17+ MacBook/PowerBook thing is one, and the new Dell's have it too I think.

[Elie]

actually my experience with laptop batteries differs from what Jammrock says in the following quote...

you should never have your battery in your laptopm if you plan on using it with AC power. That way your battery has a much less chance of getting hit by a memory issue. I don't do this mind you, but I do run my battery down a lot.

Here's what happened to me... So most of us here at work have a T60 Thinkpad, my collegues keep the battery in their laptops, I took it off, especially when plugged into A/C, now they had to replace the battery approx a year and a half later, low and behold, my battery stopped charging exactly the same timeframe as theirs, and I had it off the whole time, I litterally took care of it like it was my own!! so now I don't care anymore, I keep it plugged in and will change it in 1.5 years.

[Jammrock]

That's what you get for using a stinkpad My laptop battery is nearly 2 years old and can keep my laptop running for over 2 hours still

[Claymonkey]

BAH don't mock Thinkpads. I used to think the extra price wasn't worth it but when you can replace the battery in an old one, throw in some more ram and give it to someone three years after it was built and it not only runs snappy but looks like it came out of the box I have a hard time argueing anymore. This is why my tablet is a X41.


As for the battery issues.... yeah I agree with you Jamm for the most part... at least that after 1-2 years you shouldn't expect your battery to do anything other than last your long enough to move from one AC jack to another.

[az]

All rechrageable batteries should be drained at least once a week, once a month at the least. If you never put your battery through a full discharge/charge cycle it drastically reduces its life.

Very wrong with any Lithium-based rechargeables (which are the only ones used in modern laptops).

Actually LiIon and LiPo packs do only last for a few years, regardless of how much or how little they're charged. They also do not need to be cycled at all. And they have no memory effect. Two half cycles are exactly as harmful (! - though they will very probably die of old age after 3-5 years than due to too many cycles) to them as one full cycle.

Read this, for instance.

When I did desktop a toshiba rep said you should never have your battery in your laptopm if you plan on using it with AC power. That way your battery has a much less chance of getting hit by a memory issue. I don't do this mind you, but I do run my battery down a lot.

This was probably in the day when Laptops used to be run from NiCD or NiMH cells.

I leave the battery in my laptop all the time, and the only time I had one die was after two weeks of complete non-use (and a laptop repair, maybe they shorted it out or something). Apparently Apple's LiIon packs don't like deep discharge (which cannot happen if you leave it in the laptop and use it from time to time, because the battery's electronics prevent deep discharge and the lappy will recharge it. It can happen, however, if you leave your empty battery laying around for a long time).

EDIT: Oh, and after a year battery life on my MacBook was like it was brand new, until the repair guys killed my battery (which I then got replaced for free).

[Gurm]

And yet we are repeatedly told that the Lithium batteries in a Prius will last 10+ years... which I think are bold-faced lies.

[az]

They aren't Lithiums, they're NiMHs, because Lithium is far too expensive (which is why the Tesla's so damn expensive) and too hard to maintain properly (which is why only Tesla uses them, and no traditional automaker), never mind the explosion risk. People have been killed by Cellphone LiIons exploding, would be interesting seeing a Tesla going off

Edit: Toyota backs their claims up with an eight year warranty on the whole drive system including batteries (at least in europe). So I wouldn't care if they died after seven years. But the Prius is just too expensive. I'm intrigued by the Honda Insight, though (even though you can get a VW Golf (Rabbit) with about the same mileage using a conventional small gasoline engine).

[SteveC]

Another big factor I've found is that the batteries get damaged by the heat given off from a laptop that's used all day - another good argument for removing the batteries when not actually using them.