iPod Battery FAQ

[MacBytes]

Category: Mac Websites
Link: iPod Battery FAQ (http://www.macbytes.com/link.php?sid=20031229133615)

Posted on MacBytes.com (http://www.macbytes.com)

Approved by arn

[Awimoway]

Great article. There's a lot of misinformation out there about how to keep lithium-ion batteries strong.

It makes the oft-missed point that it is better to top off lithium-ion batteries as often as you please, although the bit about fully disharging it once every 30 discharges was news to me.

[Hemingray]

Yes, I've heard it's good to fully discharge the battery once in awhile, but I was unaware that the battery doesn't have a "memory", which is very good to hear. So, the battery has a life span of 2-3 years on average... depending on the cost of an iPod in 2-3 years, it would probably be more cost-efficient to just buy a new one I would think!

[Daveman Deluxe]

Originally posted by Awimoway
It makes the oft-missed point that it is better to top off lithium-ion batteries as often as you please, although the bit about fully disharging it once every 30 discharges was news to me.

It's common knowledge that LiIon batteries don't have a physical memory problem, but when a charge monitor circuit is added, the charge monitor tends to lose its synchronization with the physical charge level over time. That's not very well known. The vast majority of problems people have with PowerBook batteries and especially iBook batteries are because they don't deep-discharge their batteries. Do it every other week.

[punter]

When you say deep discharge you mean (talking specifically about my powerbook now) letting it run down until it sleeps itself? Is that enough or should I keep it going until it full runs out?

[Daveman Deluxe]

I used the wrong term. "Deep discharge" is when you use the battery until it goes to sleep, and then let it sleep until the computer turns off, and then letting it sit for a couple of months for good measure. If you do that, you will never be able to use your LiIon battery again.

The proper term is to use the battery until the computer is on "emergency power", which is when the computer goes to sleep for lack of battery power. THAT'S what you should do every other week or so.

[zach]

Originally posted by Daveman Deluxe
I used the wrong term. "Deep discharge" is when you use the battery until it goes to sleep, and then let it sleep until the computer turns off, and then letting it sit for a couple of months for good measure. If you do that, you will never be able to use your LiIon battery again.

The proper term is to use the battery until the computer is on "emergency power", which is when the computer goes to sleep for lack of battery power. THAT'S what you should do every other week or so.

Hm... and I thought that was BAD..

[Kingsnapped]

After a couple full discharge/recharge cycles, my iPod is still having troubles with the battry. After being charged about 24 hours, it still only has a fraction of it's battry bar. Grr...

[Awimoway]

Is it one of the newer iPods, and are you using firmware version 2.1?

It gives unreliable battery reads. I bought a newer model, but used, iPod on eBay last month. I was used to my first generation model with a much more reliable battery meter. But I asked around and found out that odd readings, such as low power after a full charge, are common.

The point is that your battery is probably fine and has a full charge. The best way to find out is to test it. Give it a full charge. Turn off all battery draining features like equalizer, sound check, backlight, clock in menu bar, random play (actually random probably doesn't wear your battery down any faster, but it doesn't hurt to be safe). Then start it playing ALL your songs. Lock it and let it play. Don't ever change which song is playing because the iPod will have to read the drive and load all new songs to the flash memory--this drains the batter faster. Then watch it and see how many hours it goes for. I did this and my iPod lasted 7 hours, 55 minutes. Since Apple advertises 8 hours battery life for 3rd generation iPods, I was fairly pleased. Now I mostly ignore the battery meter and try to remember how much I've played it between charges.


Also, every time you plug a new iPod in, it will show the Charging graphic on the screen. That doesn't mean it's really charging if you just gave it a full charge. The charge graphic is merely set on a timer. Every time you plug it in, it will show the charging graphic for a set amount of time. 4 hours, I think.

[Daveman Deluxe]

Originally posted by zap23
Hm... and I thought that was BAD..

It's not something you want to do EVERY time you use the battery. Just do it every so often to keep the charge monitor in sync with the actual battery status.

See, the lithium ion battery will last longest if you plug it in every time you can. However, over time the charge monitor circuit will get out of sync with the actual charge state of the battery. That's why you should run it down every so often because that forces the charge monitor to recalibrate itself.

[rainman::|:|]

yes you must understand that the computer (iPod) has no way of really knowing how much battery time is left, it just knows how much time a full discharge takes, and estimated based on how long since last charge, battery state before last charge, etc. If you keep charging and discharging before the battery is really low, it's estimations will become more flawed and turn into guesses. So fully discharging the battery recalibrates the battery timer and gives you more accurate information. the battery timer also affects the point at which "low battery" shows, so it can make it seem like you get better battery life.

paul