[Danoir]

Hi. I just bought a new 14" iBook. I love it. I would like to keep it a while and not have to buy a new battery before I'm done with it.

I used to work for Apple as a Student Campus Rep.. While I was in that position, they gave me one of the first IceBooks, the 500Mhz G3 Combo drive. I loved this machine. However, in the Fall of 2003, right before I gave it back, I let my roommate use it. Before long, I noticed the battery wasn't holding much of a charge. After some inquiry, I found out that he was plugging and unplugging all the time without regard to how far along in the charge the iBook was. He would be in front of the TV, so he would plug it in. He would go to another room, so he would unplug it. And so on.

Now, when I worked at RadioShack back in the day, we were always telling customers not to do this with their cordless phones. They should charge it all the way up, then drain it all the way down. I also remember when the first Li-ion battery hit for mobile phones and this wasn't supposed to be a problem anymore.

So, my question is, should I always be cycling the battery (all the way up, all the way down), or can I plug and unplug as needed? Should I cycle every once in a while? Once a week? Once a month? Once a year? Is there a good way to tell if my battery is losing the ability to hold a charge beyond gut feeling and careful observation? One example might be if my battery has about an hour left, but I need to go somewhere in an hour where I will need more battery life than that, but will not have access to a plug. Should I plug it in now to get a little charge, or not? Another example might be, if it's all the way charged up, and I want to unplug and sit in front of the couch, when I'm done watching the Simpsons should I plug it back in, or should I now try and use it all the way down.

Many thanks,
Danoir

[one sick puppy]

When I bought my iBook a couple months ago, I did some research on the battery wear down issue.

Apple recommends that you completely discharge and recharge it once every couple months if you're concerned about battery life. Also, if you're going to store it unused for extended periods of time (like a couple weeks or months) then do so with the battery at 50% power.

My electronics engineer friend, who works with rechargeable batteries, says that l-ion batteries should last a couple of years at least.

After my research, I've come to the conclusion that I shouldn't be too concerned about it. I reset my battery about once a month.

[MARINEOSX]

The new batteries don't do that for some time. They should hold a charge for at least a year as long as you calibrate it when you first get it. The Lithium-ion type of batteries only have to be fully charged once and discharged once. After that you can plug and unplug it as much as you want and it won't effect the length of charge. How ever as the charging properties inside the battery age they will begin to hold less of a charge but they should last for a long time.

[swichd]

Originally posted by MARINEOSX:
The new batteries don't do that for some time. They should hold a charge for at least a year as long as you calibrate it when you first get it. The Lithium-ion type of batteries only have to be fully charged once and discharged once. After that you can plug and unplug it as much as you want and it won't effect the length of charge. How ever as the charging properties inside the battery age they will begin to hold less of a charge but they should last for a long time.

Ideally, this is the case, but in the real world, recalibration is needed more than once.

[MARINEOSX]

Actually Li-ion batteries truly have no memory effect, as Li-ion batteries use the ions from chemicals like lithium cobalt dioxide (LiCoO2 ), and not the metals them selves. The reason that lithium metal is not used is because there can be a very hazardous reaction when this metal is used as an electrode. The reason that the metal is not used anymore is because there is thermal run off from shorted lithium dendrites, and will reach melting temperature and explode. Have you ever heard of someone's cell phone exploding when they where on it? This is because they had used the actual metal inside the battery. The reason that they are used is because they offer twice the energy density of a NICAD battery, and have no memory. The reason that you calibrate it is because you want to ensure that it receives a full charge. Not to set it's actual charging capacitance. Here is a link that you can look at. This is one place that I based this off of.


http://www.computerhope.com/issues/ch000350.htm

I almost forgot. The Li-ion batteries generaly have a 500 to 800 charging cycle life.

[Wiskedjak]

Honestly, I don't trust Apple to tell me how to maintain my battery when they seem intent on killing it themselves. A few weeks before updating to 10.3.5 I was getting about 1.5 hours out of my 3yr old iBook. 3 days after the update it was down to 20 minutes.

[brickcam]

I highly recommend a utility called CapacityMeter to painfully watch as your battery's max capacitance degrades.