How do you maximise the life of a lithium-ion battery?

December 30, 2003 1:04 AM

With the recent IPod fiasco now behind us, the word is out that to maximize the useful lifespan of lithium Ion batteries, its best not to draw them down to empty (ever) and to keep them topped off and charging when not in use. Yet, when the units ship after manufacture, the batteries are apparently alltogether uncharged. My Question is, if you are planning not use your IPod or other Lithium Ion powered device for a long time, must they be left charging for all that time or is there better means of long term non use and storage that doesn't hose the battery pack?
posted by Fupped Duck to Technology (9 answers total)

My experience with Li-ions has led me to discharge to around 40% and store in a cool dry place for longer-than-a-few-days-term storage. I don't have hard evidence to back this up, though -- but it seems to work well for me.
posted by j.edwards at 1:53 AM on December 30, 2003

I am using a sony Li-Ion battery for my laptop, I've always kept it fully charging since it always sits on my desk. Now it can't hold more than a 20 minute charge. It's only 8 months old and I guess I have to buy a new one.
posted by sebas at 4:33 AM on December 30, 2003

This is interesting. I was of the camp to leave all my Li-ion gizmos charging when not in use, but then in my new camera's [Canon Powershot G5] user guide I came across this little gem:

"This is a lithium ion battery pack so there is no need to completely use or discharge it before recharging. It can be recharged at any time. However, since the maxium number of charge cycles is approximately 300 times (battery life), you are recommended to only charge the battery pack after having discharged it completely to prolong battery life." [emphasis mine]

This is the first gizmo I've owned that had that advice. Most Li-Ion devices tout not having the memory issues that NiMH batteries, but nothing about the finite life of the Li-Ion cells. In way it makes sense, there can only be a finite number of times you'd be able to recharge a battery.

Reading between the lines, it sounds like Canon's recommendation would be similar j.edward's.
posted by birdherder at 4:54 AM on December 30, 2003

I was reading up on the iPodlounge forums and came across these links:

How to prolong lithium-based batteries and How to charge. I'm still unsure as to how this applies to the iPod exactly. I leave mine in the dock at all times I'm not using it elsewhere, but I'm not sure if it affects the battery life by doing that. I just find the idea that you have to remove the iPod from the dock whenever you're not listening to music kind of dumb, since it's obviously designed as a stand.
posted by Big Fat Tycoon at 5:03 AM on December 30, 2003

not sure what you mean by the fiasco being behind us... i still have an ipod battery without an easy user-replaceable answer (i.e. not having to send it to apple), as i'm sure many others do.

"Yet, when the units ship after manufacture, the batteries are apparently alltogether uncharged."

when i recieved my ipod shipped from apple about a month ago, it was charged. my friend, who just bought his ipod from an apple store a week ago, also had his charged when he took it out of the box.
posted by lotsofno at 5:28 AM on December 30, 2003

Response by poster: I remember following a link on /. once that lead to an excellent and very detailed technical FAQ on rechargeable batteries of all types written by an engineer who designed rechargable arrays of batteries.

I tried googling for it but these days, googling for rechargable battery FAQ gets you a 1000 links for battery merchants and no sign of the FAQ. . .

Lotso: IPods are always on. Left alone long enough, they drain the battery down to nil. Yours and your friend's must have been freshly plucked from the apple tree.
posted by Fupped Duck at 7:07 AM on December 30, 2003

Apple ships it partially charged. My iPod which I got at the end of January arrived with a minimal charge. Since I bought it from Apple directly, I could track the package coming in from Taiwan, where the iPods are manufactured, so I don't know if the newer iPods come with more charge, but at least mine which apparently came from Apple's warehouse/factory was barely charged.

lotsofno, you can buy a replacement iPod battery from ipodbatetery.com for $49.
posted by riffola at 7:26 AM on December 30, 2003

My Sony Li-Ion pack says to discharge fully before recharging, reducing the number of times you have to charge it.
posted by Keyser Soze at 11:14 AM on December 30, 2003

I've heard the finite-number-of-charges thing in the cellular world, too - was told once that one could expect maybe 500 charges for your lithium ion battery, lifetime, so if you have a habit of charging every day, you can bet on a year and a half lifetime, tops.
posted by danwalker at 7:17 PM on December 30, 2003