Laptop batteries.

I would like some input from others here who own laptops. I have an Asus U81A that I bought 7 years ago. With conditioning, this laptop still runs for 5 hours on a single full charge. Personally I know no other friend who has a laptop this old that will hold a charge. From talking to people what I have gathered is that the "normal" lifetime of a battery is between 2-3 years before capacity goes down to less than an hour. But also the trend is that these people leave the laptop charged every chance there is. Never cycling the battery. The companies boast no memory but I seem to have a 7 year experiment that says otherwise. I know this is one case in everyone that I know. But I really don't know anyone else with a 7 year old laptop with 5 hour run time.

What I have done since day one is to always drain the battery down to between 7-12 percent and charge to full. Never leaving it plugged in at full charge for more than 8 hours. And this seems to have worked better than I have imagined. I have estimated I have charged this battery pack over 2500 times. Brand new the battery life was 7 hours. 7 years later and it will still hold a charge for 5 hours. I have no idea what batteries these are but they are good stuff.

At the time I bought this laptop I wanted quality and simplicity. I didn't care for HD screen and an awesome video chip. I wanted a sound processor, high RAM, good battery life, and plenty of memory. All for 800 dollars. Nowadays 800 will get you a crazy laptop. But I really see no need to get a new laptop while this runs Windows 7 just fine and BEATS the run time of new laptops today. End my nerd rant.

What you are doing is correct. In the event a laptop battery starts to show signs of death, its salvage time. Most have 6 cells. If you disassemble the pack to individual cells, you can find the bad one (1 cell). The good ones can be used to repair power tool batteries or for flashlights that use 18650's. Even the "bad" cells hold up well in flashlights!

Experiencing a similar thing with my mobile phone (10+ yrs old). Have always cycled the battery, that is: wait till -largely- empty before recharging. And then disconnect from charger, so it's back to discharging again. Result is that battery is always somewhere between empty and fully charged, never sits empty or 100% charged for extended period of time, average state-of-charge maybe 60% or so.

Very long standby times of my phone helped to keep the cycle count 'low' (well might be up to 500+ cycles now). Yes the battery has lost a large % of its original capacity, but given its age has held up well. :thumbsup:

For a laptop, there's another important factor: heat. Which might be more damaging to battery life than how it's cycled. For longest possible use, it might be optimal to charge ~50%, pull the battery out and store elsewhere. Only to insert & do a few cycles occasionally. But this also removes the UPS function a laptop battery has. And it may degrade anyway over time even if in storage. So I tend to think of a laptop battery as a 'consumable' of sorts, if it lasts much longer than 3-5 years or so you're just lucky. For that matter, if your laptop lasts 5+ years, you're also lucky... :laughing:

That's how i've done my laptop. New, it would run on the lowest screen setting for about an hour and 45 minutes. now 3+ years later, it runs about an hour 15 minutes. I run it down till the little screen pops up and says battery is low, which is at 10%. let it charge up to full. Every now and then i'll charge it at around 50% or 60%. My battery still works fine, but the computer itself is another story. Lets just say, i'm sick of DELL computers, and this one has been on my bad side and blue screening lately and for the life of me can't trace down the problem. I'm about 2 seconds away from introducing it to mr. sledgehammer!

ElliDee said:

The companies boast no memory but I seem to have a 7 year experiment that says otherwise. I know this is one case in everyone that I know. But I really don't know anyone else with a 7 year old laptop with 5 hour run time.

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Memory is a different phenomenon, relating to always discharging a battery to the same point over and over.

Treating a battery well does require actually using it, but using it gently, as you have done. Don't let it sit on charge longer than needed, don't drain it too far, etc.

The quality of the cells themselves makes a difference too. Higher quality materials and better balance between cells will lead to a longer life.

I just saw this topic and I would like to give my (bad) experience with laptop battery and also I have a question. So, I've owned a Toshiba laptop for 5 years. The original battery was losing it's capacity very quickly and after 1.5 years it was completely dead; the laptop wasn't able to recognize it. I put it out and after a few months I put it back in. The laptop recogized it but it lasted for 5 minutes on battery. Then I bought a new one, genuine Toshiba, from eBay. I started pulling it out everytime the laptop was a long time connected to the charger. And now, 2 years ago, it's still working but it has lost 50% of its capacity. I think that the problem is in heat: this laptop is a real heater: the CPU is almost all the time above 80c and when playing games, it reaches 100c. I cleaned it and replaced the thermal paste a few times but it didn't help a lot. So the battery was hot as well and I believe that the heat is destroying it.

3 months ago I bought a new Asus laptop. The problem with this laptop is that the battery is not removable! It's fixed inside the laptop and can't be pulled out without dissasembling the whole laptop. My question is: how should i use my laptop to prolong the battery's life? My laptop is 90% of the time connected to charger and I can't pull the battery out. But I noticed that, once it reaches 100%, it says "Plugged in, not charging" and it lets the battery discharge for a few % before recharging it again. Furthermore, the cooling is so good that the battery doesn't heat up no matter how how the CPU is. The battery is located under the palm rest and I tried the heaviest games and stress tests and the palm rest altogether with the battery is cold all the time. So the heat won't be problem.

But, being constantly plugged in can be a problem, right? Should I use the battery more often? And, I suppose that it's a li-ion so is it better to let it completely discharge or to discharge to 50% for example and then plug it back in?

I wish I have known this a lot earlier. My 4-year old laptop is constantly plugged and I seldom use the battery unless it's really needed. Now, my battery's life expectancy runs less than an hour.

Today's battery's

12 Samsung icr1865022e 2200mah new
9 Sanyo ur18650y 2000mah new

They are all about 5y old and all had even voltage around 3.85

Will be interesting to see how they hold voltage and so some mah tests.

It's amazing what you can get when you ask nicely.


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I have a brand new laptop here that has broken down just outside warranty and this afternoon it is being binned in the local council run centre.I have no intention of messing about trying to save a few cents on batteries and much prefer to buy bona fide batteries from a vendor.

mcnair55 said:

I have a brand new laptop here that has broken down just outside warranty and this afternoon it is being binned in the local council run centre.I have no intention of messing about trying to save a few cents on batteries and much prefer to buy bona fide batteries from a vendor.

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+1.

I've salvaged a few but in all honesty, I have better things to do with my time; those weld tabs are a pain in the rear to smooth down to prevent them damaging springs/contacts.

Whenever I'm near a mains outlet. I take the battery out and run it directly from the mains. That means for 90% of the time, the battery life clock stops ticking. For the other times after I had to run it on battery, I charge it back up to about 95% full. That is it. Then I take the battery out and go back to running on mains electricity. The battery outlasts my laptop.