Sunday, January 11, 2004

The 2-3 year lifespan of Lithium-Ion batteries (Washington Post)

Batteries Can't Keep Up (
Lithium ion batteries, the battery type most commonly used inside laptops and the flashy gadgets that early adopters of new technology lug everywhere in their pockets, are the most lightweight, powerful and low-maintenance batteries around....

But they have one drawback: a limited lifespan. Lithium ion batteries are particularly susceptible to aging; as soon as one leaves the manufacturing line, its countdown begins. A typical lifespan is two to three years, whether it is ever used or not -- as some disgruntled owners of Apple Computer Corp.'s iPod found when their digital music players suddenly went dead. A huge hullabaloo ensued.

...Though Rio offers players with both replaceable and built-in battery options, Hastings said that most consumers care more about a player's looks than its onboard battery lifespan when comparison shopping.

Some gadget makers have programs to replace batteries when they've worn out, some don't. Apple eventually agreed to set up a battery-replacement program for the popular digital music player (iPod owners can now have their batteries replaced for $99). Handheld maker PalmOne doesn't have a program in place to replace the batteries of old handhelds; PalmOne's vice president of hardware engineering, Gregg Zehr said that most users choose to upgrade to a new handheld when the battery wears out.

This is a fascinating story, there are really several things to learn from the LiOn history:

1. It takes quite a while for these things to emerge. LiOn batteries have been in heavy use for at least five years, but it's only in the past six months that their lifespan and other characteristics have started to be known to Geeky types. This washington post article is the first summary I've seen for a wider audience. As usual the trade journals had nothing to say. I do miss the old BYTE! I'm sure this was well known by engineers in this domain.

2. The real problem is not so much the short lifespan of LiOn batteries, or even their high replacement cost, but rather that quite expensive devices were sold with a fixed non-replaceable battery. You can easily pay $500 to $1000 for a PDA or iPod that has a 2 year lifespan. In contrast a laptop can have a 4-8 year lifespan. A PDA or iPod is thus more costly than a laptop. This doesn't have to be true.

3. Customers have not made wise choices, but manufacturers could have educated them better. Or maybe not.

4. iBook customers noted the same problem as iPod customers, but iBook batteries are replaceable.

5. If you buy a laptop towards the end of a production cycle, your battery may be less fresh and die sooner.

6. I'm not sure this is equally true for all LiOn batteries. In particular I think SONY may have some useful "tricks" that are somewhat underappreciated.

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