Laptop Battery Life

[alimoalem]

Hey everybody. I was wondering, do you guys have tips on maintaining a laptop's battery life? I recently bought a Thinkpad T400 and want to do my best to keep the battery good.

My understanding is fully discharge, then charge. Is this wrong?

Anything else? Thanks.

 

[VinDSL]

Okay... this is my opinion, based on my own experience(s).

Personally, I run on AC whenever I can (which is most of the time) and when I'm on AC, I remove the battery from my lappy/netbook.

When I HAVE to use the battery, I charge it to 100% (of course) - run it down until I get a low-battery notice, then I charge it to 100% again. When I'm able to use AC again, I run the battery down to 50% and pull it.

Put another way... I NEVER store a fully charged or fully drained battery - and I NEVER leave my battery in my lappy when it's on AC (unless I'm charging it). This procedure has allowed me to use the same battery(s) for years!

Many of my friends, on the other hand, leave their batteries in their lappys/netbooks all the time, whether they're on AC or not - and they're lucky if they get a year of usage out of their batteries - no kidding! Funny as hell to watch, actually - they always *think* it's the battery's fault...

There's really NO reason to run a Li-ion battery until it's flat - they don't have a memory, so called. The thing is, you don't want to charge them too often either, because a Li-ion battery will only recharge about 300 times before it needs to be replaced.

Anyway, that's what I recommend.

 

[corkyg]

Echo Vin's comments. The useful life of a steadily used lappy battery is about 3 years. Each time it is recharged, it it has a slightly shorter duration and lifespan. Like Vin, I use my battery power only when forced to by mobility.

I have a Lenovo T60, and two batteries. One 9 cell and one 6 cell. I save the 9 cell for long trips and use the 6 cell at home.

 

[deputc26]

By battery life I think you mean "cycle life", there are MANY variables that go into how long your battery lasts but nearly ALL laptop batteries are Lithium Ion with Cobalt Oxide cathodes. Here are the factors that effect their life.

1. DoD, Depth of Discharge, the deeper you discharge the battery the shorter it's cycle life (cycle life is defined as being over when the battery only holds 80% of it's original capacity) discharging to ~40% is optimal. Conversely charging the battery to 100% also shortens the life, most laptop bats are actually at 90% when they show 100% and stop charging.

2. C rate. A 10 amp hour battery producing 10 amps is discharging at 1C. A 10 ah battery producing 20a is discharging at 2C. Anything above 1C starts to decrease the cycle life of the battery (though not all chemistries are like this, this figure is for li-ion with cobalt oxide cathode)

3. Temperature, higher temperatures increase the amount of energy available for a given charge (to a point) but decrease the cells cycle life, temps over 40deg C have an exponentially increasing (with T) negative affect on cycle life. Also if temps are below or near freezing you lose cycle life AND the energy available per charge is decreased. THE EFFECTS OF #2 AND #3 ARE MULTIPLIED, A HIGH C RATE AT HIGH TEMP IS THE WORST.

4. There are many other smaller factors specific to exact chemistries I have heard rumors that it is good to vary the DoD. Simply leaving the battery in a really hot place (car in the sun) or operating a laptop with poor cooling that heats up a lot will decrease the batteries life even when it is not in use. As noted above storing in in a very high or very low state of charge will also decrease your cycle life.

 

[TheStu]

Well, I don't remove the battery from my laptop ever really. I had one battery go bad on me, but that was from a bad batch and was replaced for free. My latest I have had almost 2 years now IIRC and it still nets me anywhere from 1.5-3 hours of life depending on use (when brand new it was closer to 2-3.5 hours). My mother has an almost identical laptop, and her battery still gets her 3-3.5 hours of life for her use (mine is lower because I watch a lot of videos/dvds) which is mostly web surfing. She is particularly good about using it on battery, letting it run down, recharging it and then doing it again. She has hundreds of cycles on the battery and still gets good battery life.

I am not quite so strict, but do run it on battery every time I think that I am going to be away from my charger for a couple of hours (so, chilling with friends, going to panera, going to a customer's house, that sort of thing). After 180 or so cycles on my battery I currently have about 90% capacity left.

So, VinDSL's solution might be the best for the battery, but I find my situation acceptable for my usage. I get reasonable battery life without the compromise of having to pull the battery every time I have my computer tethered (at which point my laptop is now just as vulnerable to electrical problems as my desktop)

 

[alimoalem]

Thanks for all your posts. It's really helped